The Good, Bad, Ugly, and Uglier
Accomplishing pure science is not easy. Why? It is not easy because we are human with our personal and cognitive biases, emotional involvement, and so forth and so on.
—Frank R. Spellman
Introduction
It is not uncommon for people to have conflicting views about the benefits and/or drawbacks of science. Science is viewed by many as the engine of maintaining a healthy lifestyle; the engine of prosperity; or, the engine that propels the vehicle that maintains the so-called good life. However, there are other views that hold contempt for the consequences and failings of science. With regard to the failings, we ask, “Are the failings really a result of science itself, or of the failure of those who should know better?” (the ones who are tasked with correctly carrying out the precepts or rules of science.)
In this chapter, as the title states, we highlight the good, the bad, the ugly, and an example of one of the ugliest aspects of a failure of science (or more correctly, of those who fail to follow the precepts of science). We make no apology for the science itself, none is required, we champion science; instead, our intent is to show that when properly employed science is extremely beneficial, even in bad situations. Simply, and stated differently, we profess that science itself is the observation and analyzing of facts. The reality is there is nothing good or bad about science. It is like a chainsaw, which may be used to cut up dead falls or branches from trees, or cut down the trees for product use or for land use, but, at the same time could be used to cut up humans in a most bloody and gory fashion. It is up to humans how we use it.
The Good
A Sherlock Holmes-Type at the Pump1
He wandered the foggy, filthy, garbage strewn, corpse-ridden streets of 1854 London searching, making notes, always looking . . . seeking a murdering villain (no; not the Ripper, but a killer just as insidious and unfeeling)—and find the miscreant, he did. He took action; he removed the handle from a water pump. And, fortunately for untold thousands of lives, his was the correct action—the lifesaving action.
He was a detective—of sorts. No, not the real Sherlock Holmes—but absolutely as clever, as skillful, as knowledgeable, as intuitive—and definitely as driven. His real name: Dr. John Snow. His middle name? Common Sense. Snow’s master criminal, his target? A mindless, conscienceless, brutal killer: cholera.
Let’s take a closer look at this medical super sleuth and at his quarry, the deadly cholera—and at Doctor Snow’s actions to contain the spread of cholera. More to the point, let’s look at Dr. Snow’s subsequent impact on water treatment (disinfection) of raw water used for potable and other purposes.
Dr. John Snow
An unassuming—and creative—London obstetrician, Dr. John Snow (1813–1858) achieved prominence in the mid-nineteenth century for proving his theory (in his On the Mode of Communication of Cholera) that cholera is a contagious disease caused by a “poison” that reproduces in the human body and is found in the vomitus and stool of cholera patients. He theorized that the main (though not the only) means of transmission was water contaminated with this poison. His theory was not held in high regard at first, because a commonly held and popular counter-theory stated that diseases are transmitted by inhalation of vapors. Many theories of cholera’s cause were expounded. In the beginning, Snow’s argument did not cause a great stir; it was only one of many hopeful theories proposed during a time when cholera was causing great distress. Eventually, Snow was able to prove his theory. We describe how Snow accomplished this later, but for now, let’s take a look at Snow’s target: cholera.
Cholera
According to the U.S. Centers for Disease Control (CDC), cholera is an acute, diarrheal illness caused by infection of the intestine with the bacterium Vibrio cholera. The infection is often mild or without symptoms, but sometimes can be quite severe. Approximately 1 in 20 infected persons have severe disease symptoms such as profuse watery diarrhea, vomiting, and leg cramps. In these persons, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours.
Did You Know?
You don’t need to be a rocket scientist to figure out just how deadly cholera was during the London cholera outbreak of 1854. Comparing the state of “medicine” at that time to ours is like comparing the speed potential of a horse and buggy to a state-of-the-art NASCAR race car today. Simply stated: Cholera was the classic epidemic disease of the nineteenth century, as the plague had been for the fourteenth. Its defeat was a reflection of both common sense and of progress in medical knowledge—and of the enduring changes in European and American social thought.
How does a person contract cholera? Good question. Again, we refer to the CDC for our answer. A person may contract cholera (even today) by drinking water or eating food contaminated with the cholera bacterium. In an epidemic, the source of the contamination is usually feces of an infected person. The disease can spread rapidly in areas with inadequate treatment of sewage and drinking water. Disaster areas often pose special risks. For example, the aftermath of Hurricane Katrina in New Orleans raised concerns for a potential cholera outbreak.
Cholera bacterium also lives in brackish river and coastal waters. Raw shellfish have been a source of cholera, with a few people in the United States having contracted it from eating shellfish from the Gulf of Mexico. The disease is not likely to spread directly from one person to another; therefore, casual contact with an infected person is not a risk for transmission of the disease.
Flashback to 1854 London
The information provided in the preceding section was updated and provided by the Centers for Disease Control (CDC) in 1996. Basically, for our purposes, the CDC confirms the fact that cholera is a waterborne disease. Today, we know quite a lot about cholera and its transmission, as well as how to prevent infection and how to treat it. But what did they know about cholera in the 1850s? Not much. However, one thing is certain: They knew cholera was a deadly killer. And that was just about all they knew—until Dr. Snow proved his theory. He believed that cholera is a contagious disease caused by a poison that reproduces in the human body and is found in the vomit and stool of cholera victims. He also believed that the main means of transmission was contaminated water.
Dr. Snow’s theory was correct, of course, as we know today. The question is, how did he prove his theory correct twenty years before the development of the germ theory? The answer provides us with an account of one of the all-time legendary quests for answers in epidemiological research—and an interesting story!
Dr. Snow proved his theory in 1854, during yet another severe cholera epidemic in London. Though ignorant of the concept of bacteria carried in water (germ theory), Snow traced an outbreak of cholera to a water pump located at the intersection of Cambridge and Broad Street (London). How did he isolate this source to this particular pump? He began his investigation by determining in which area in London persons with cholera lived and worked. He then used this information to map the distribution of cases on what epidemiologists call a “spot map.” His map indicated that the majority of the deaths occurred within 250 yards of that communal water pump. The water pump was used regularly by most of the area residents. Those who did not use the pump remained healthy. Suspecting the Broad Street pump as the plague’s source, Snow had the water pump handle removed and thus ended the cholera epidemic.
Sounds like a rather simple solution, doesn’t it? For us, it is simple, but remember in that era, aspirin had not yet been formulated—to say nothing of other medical miracles we now take for granted—antibiotics, for example. Dr. John Snow, by the methodical process of elimination and linkage (Sherlock Holmes would have been impressed—and he was), proved his point and his theory. Specifically, he painstakingly documented the cholera cases and correlated the comparative incidence of cholera among subscribers to the city’s two water companies. He learned that one company drew water from the lower River Thames. While the other company obtained water from the upper Thames. Snow discovered cholera was much more prevalent in customers of the water company that drew its water from the lower Thames, where the river had become contaminated with London sewage. Snow tracked and pinpointed the Broad Street pump’s water source. You guessed it: the contaminated lower Thames, of course.
Dr. Snow, the obstetrician, became the first effective practitioner of scientific epidemiology. His creative use of logic, common sense (removing the handle from the pump), and scientific information enabled him to solve a major medical mystery—to discern the means by which cholera was transmitted—and earned him the title “the father of field epidemiology.” Today, Dr. John Snow is known as the father of modern epidemiology.
Pump Handle Removal—To Water Treatment (Disinfection)
Dr. John Snow’s major contribution to the medical profession, to society, and to humanity in general can be summarized rather succinctly: He determined and proved that the deadly disease cholera is a waterborne disease (Dr. Snow’s second medical accomplishment was that he was the first person to administer anesthesia during childbirth).
What does all of this have to do with water treatment (disinfection)? Actually, Dr. Snow’s discovery—his stripping of a mystery to its barest bones—has quite a lot to do with water treatment. Combating any disease is rather difficult without a determination of how the disease is transmitted—how it travels from vector or carrier to receiver. Dr. Snow established this connection, and from his work, and the work of others, progress was made in understanding and combating many different waterborne diseases.
Today, sanitation problems in developed countries (those with the luxury of adequate financial and technical resources) deal more with the consequences that arise from inadequate commercial food preparation, and the results of bacteria becoming resistant to disinfection techniques and antibiotics. We simply flush our toilets to rid ourselves of unwanted wastes, and turn on our taps to take in high quality drinking water supplies, from which we’ve all but eliminated cholera and epidemic diarrheal diseases. This is generally the case in most developed countries today—but it certainly wasn’t true in Dr. Snow’s time.
The progress in water treatment from that notable day in 1854 [when Snow made the “connection” (actually the “disconnection” of handle from pump) between deadly cholera and its means of transmission] to the present reads like a chronology of discovery leading to our modern water treatment practices. This makes sense, of course, because with the passage of time, pivotal events and discoveries occur—events that have a profound effect on how we live today. Let’s take a look at a few elements of the important chronological progression that evolved from the simple removal of a pump handle to the advanced water treatment (disinfection) methods we employ today to treat our water supplies.
After Snow’s discovery (that cholera is a waterborne disease emanating primarily from human waste), events began to drive the water/wastewater treatment process. In 1859, 4 years after Snow’s discovery, the British Parliament was suspended during the summer because the stench coming from the Thames was unbearable. According to one account, the river began to “seethe and ferment under a burning sun.” As was the case in many cities at this time, storm sewers carried a combination of storm water, sewage, street debris, and other wastes to the nearest body of water. In the 1890s, Hamburg, Germany, suffered a cholera epidemic. Detailed studies by Koch tied the outbreak to the contaminated water supply. In response to the epidemic, Hamburg was among the first cities to use chlorine as part of a wastewater treatment regimen. About the same time, the town of Brewster, New York, became the first U.S. city to disinfect its treated wastewater. Chlorination of drinking water was used on a temporary basis in 1896, and its first known continuous use for water supply disinfection occurred in Lincoln, England, and Chicago in 1905. Jersey City, New Jersey, became one of the first routine users of chlorine in 1908.
Time marched on and with it came an increased realization of the need to treat and disinfect both water supplies and wastewater. Between 1910 and 1915, technological improvements in gaseous and then solution feed of elemental chlorine (Cl2) made the process more practical and efficient. Disinfection of water supplies and chlorination of treated wastewater for odor control increased over the next several decades. In the U.S., disinfection, in one form or another, is now being used by more than 15,000 out of approximately 16,000 Publicly Owned Treatment Works (POTWs). The significance of this number becomes apparent when you consider that fewer than 25 of the 600 plus POTWs in the U.S. in 1910 were using disinfectants.
Pump Handle Removal: Lessons Learned
There are a number of lessons to be learned from the actions of Dr. John Snow when he removed the pump handle from the pump in London and effectively stopped the cholera outbreak. For our purposes there are four important lessons:
1. Dr. Snow’s experiments with finding the culprit that caused the 1854 cholera outbreak in London demonstrate the most important aspect of why science is important; why we need science and why it is important. Simply, science saves lives. If there is anything more important than this, we can’t find it.
2.We simply can’t go through life ignorant of our surroundings and the laws that literally make the world go round. With pressing problems such as the swine flu (H1N1 virus); the prospects of global climate change and/or global warming or global freezing and pending sea level rise; worldwide economic problems which many people feel are going to require science and innovation to point the world’s economies in the right direction; growing concerns about environmental pollution problems affecting all four environmental mediums (air, water, soil, and biota); the pending energy crisis and the urgent need to jumpstart science and technology to bring renewable energy sources on line. All of these issues are important, and obviously, they certainly point to a need for science. In light of all of this we can’t point out strongly enough the importance of understanding of science for members of a democratic society. We simply cannot be ignorant of science and the facts. Think about it. How are we to participate in a democracy if we don’t understand basic science concepts? When the naysayer who warns us for the need for this or for that because if we take no action doomsday is surely near, and when these so-called experts justify their expertise simply because of their positions of authority or power, we need to be able to filter the information to determine the truth. Science is the filter—the ultimate micro-filter.
3. From the above account of Dr. Snow’s activities in attempting to find the cause of the 1854 cholera epidemic in London, it should be apparent to the reader that he followed a step-by-step procedure in finding the culprit. We can say he used his toolbox (the scientific method) to track down the dreadful killer. In this particular case, Dr. Snow used the six major tools in the scientist’s toolbox. For instance:
• Observation—Dr. Snow observed that several residents of London were becoming ill and many succumbed to some unknown agent.
• Question—Dr. Snow asked why? Why are some Londoners getting ill and dying?
• Hypothesis—Dr. Snow believed sewage dumped into the river or into cesspools near town could contaminate the water supply, leading to a rapid spread of disease. In 1883 a German physician, Robert Koch, took the search for the cause of cholera a step further when he isolated the bacterium Vibrio cholerae, the “poison” Snow contended caused cholera. Dr. Koch determined that cholera is not contagious from person to person contact, but is spread only through unsanitary food or water supplies.
• Experiment—Dr. Snow made a spot map of the downtown London area. The spots indicated locations where people contracted and died of cholera. His spot map indicated that most of the fatalities occurred in proximity to the Broad Street pump. Thus, he had the handle to the Broad Street pump removed.
• Data recording/collecting—Dr. Snow’s data collected after removing the pump handle from the Broad Street pump indicated immediate results in that no further occurrences of cholera occurred in the Broad Street area.
• Conclusion—Dr. Snow concluded that London’s 1854 cholera epidemic was caused by sewage in the water pumped by the Broad Street pump.
4. The fourth lesson learned from Dr. Snow’s cholera experiment is that science is flexible, never bends the truth and has many branches. From acoustics—the branch of science related to the study of transmission of sound waves, to zoology—a branch of biology (another science) that is related to the study of animal kingdom, including evolution, classification, distribution, structure, habits, and embryology of animals. The branches of science are too numerous to list here; therefore, we choose, for the moment, to focus on one branch, Dr. Snow’s branch: epidemiology— the study of cause and distribution of diseases in human population. We feel epidemiology is an excellent branch of science to focus on because it allows us to demonstrate that different branches can use the scientist’s toolbox (scientific method) in standard form, or it can be modified to suit particular needs and uses. We demonstrate this modification in the next section.
EpidemioloGIt’s Toolbox
Earlier we discussed some of the early accomplishments of the preeminent trail-blazing disease detective, Dr. John Snow, to show the value of science (the “Why” of science; why it is important to all of us) in regards to one of science’s most important (if not the most important) goals and achievements—it saves lives. It is important to point out that Dr. Snow, as mentioned earlier, worked on his own without the benefit of the microscope, knowledge of germ theory of disease, Koch’s postulates, and Louis Pasteur’s anti-spontaneous generation experiments and his findings in the development of vaccines (e.g., rabies vaccine).
Before we go any further, it is important to provide a brief description of the terms and occurrences just mentioned.
• Microscope—When Antonie van Leeuwenhoek (1632–1723), known as “the father of microbiology,” improved the microscope, he was able to observe single celled organisms that he first referred to as animalcules, and which we now refer to as microorganisms. Van Leeuwenhoek’s improved microscope was one of the most important tools added to the scientist’s toolbox; its inclusion allowed formation of germ theory of disease.
• Germ Theory—Without a doubt the germ theory of disease is the single most important contribution by the science of microbiology to the general welfare of the world’s people, perhaps the single most important contribution of any modern scientific discipline.
• Koch’s postulates—Robert Koch (1870s) developed Koch’s Postulates which are a sequence of experimental steps for directly relating a specific microbe to a specific disease.
Koch’s postulates are as follows:
1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy animals.
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism.
4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
Note: Koch later abandoned the universalist requirement of the first postulate altogether when he discovered asymptomatic carriers of cholera and, later, of typhoid fever.
In addition to Koch’s postulates, (important tools in the scientist’s toolbox), Koch played an important role in the development of the use of agar (gelatinous substance from seaweed used as culture medium) in petri dishes (shallow dish used to culture or grow cells) as solid medium; he also invented nutrient broth and nutrient agar. Koch’s main discoveries include Bacillus anthracis, Mycobacterium tuberculosis, and Vibrio cholera.
• Key to developing the germ theory of disease was a refutation of the concept of spontaneous generation; that is, the belief that living things can arise from non-living things. Louis Pasteur (1860s) definitively demonstrated that microorganisms are present in air but not created by air.
Unlike Dr. Snow and his peers, today we have the benefit of many scientific discoveries and digital hardware and software that have made life leap years better for many people on earth. The practice of science is somewhat easier than it was in the past. This is not to say, however, that we are finished with scientific discoveries; not at all. We are just scratching the surface of scientific knowledge and must continue on and beyond the work of Dr. Snow, van Leeuwenhoek, Koch, Pasteur, and many others. Fortunately, science and scientists are doing just that.
To continue our discussion on why science is important we have chosen an epidemiology example to help demonstrate the importance of science to all of us. Keep in mind that we could have chosen major achievements in any branch of science to help us answer the question, “Why science?” We chose epidemiology because health and life are important to us all, and also because of its currency to the issues of the day; for example, pandemic outbreaks of swine flu. Moreover, epidemiology is a major tool in the scientist’s toolbox used by disease detectives of many stripes—epidemiologists, laboratory scientists, statisticians, physicians and health care professionals, and public health professionals—to get to the root of health problems in the community, whether the problem is a measles outbreak on a small college campus or a global influenza pandemic (H1N1), an increase in homicide in a single community or a national surge in violence, or a localized or widespread rise in cancer (CDC 2009).
Disease Causation
Like the crime scene investigators seen on TV in CSI and Forensic Files, disease detectives begin by looking for clues. They systematically gather information about what happened—Who? What? When? Where? Who is sick? What are their symptoms? When did they get sick? Where could they have been exposed to the illness? Ignoring Mark Twain’s paraphrasing of Benjamin Disraeli when he said, “There are three kinds of lies: there’s lies, damned lies and statistics”—using (non-lying) statistical analysis, disease detectives study the answers to these questions to find out how a particular health problem was introduced into a community. Disease detectives then use what they have learned to prevent further illness.
It is important to note that although we use analytic epidemiology to search for causes of disease; this is not a straightforward matter. And this is one of the major turn-offs about science. People on the outside looking inward or observing or listening to progress (or lack of progress) want the 411 on the topic and not a bunch of gobbledygook nonsense that explains everything in cryptic language when it could just as easily be stated in Jack and Jill “Went Up the Hill” basic language that explains that we have failed or we have succeeded, period. If we wish to attract people to science, we must first speak in language common to all—we can’t have a failure to communicate.
Let’s get back to the 411 on why searching for causes of disease is not a straightforward matter, and hopefully we can explain it in plain, understandable fashion. First, not all associations between exposures and disease are causal relations. In addition, the accepted models of disease causation all require the precise interaction of factors and conditions before a disease will occur. Finally, the concept of cause itself continues to be debated as a philosophical matter in the scientific literature—pointing again to the problem with communication and the gobbledygook that is confusing at best. Nonetheless, we provide the following model and guidelines as a straightforward, everyday framework for considering causation at a practical level.
For the purpose of clarity in this text, we use CDC (1992) definitions to define cause of disease as a factor (characteristic, behavior, event, etc.) that influences the occurrence of disease. Simply, an increase in the factor leads to an increase in disease. Reduction in the factor leads to a reduction in disease. If disease does not develop without the factor being present, then we term the causative factor “necessary.” If the disease always results from the factor, then we term the causative factor “sufficient.” Exposure to mycobacterium tuberculosis (MTB—a pathogenic bacterial species discovered in 1882 by Koch) is necessary for tuberculosis to develop, but it is not sufficient, because not everyone infected develops disease. On the other hand, exposure to a large inoculum of rabies virus is a sufficient cause in a susceptible person, since clinical rabies and death will almost inevitably occur.
A variety of models (another tool in the scientist’s toolbox) of disease causation have been proposed. Models are purposely simplified representations. In this instance, the purpose of the model is to facilitate the understanding of nature, which is complex (and we can’t make it any simpler or explain Mother Nature other than to say, she is the boss). One of the models is discussed below.
The Epidemiological Triangle
As mentioned, Dr. John Snow was truly a pioneer; he delved into the unknown where his curiosity was his torch and common sense his road map to discovery and the truth. As pointed out earlier, Dr. Snow’s detective work in determining causal factors related to the 1854 London cholera outbreak (and his eventual saving of countless numbers of lives of Londoners and others) did follow the tenets of what we call the scientific method—the scientist’s toolbox—but it is important to point out that modern epidemiology has taken the six step scientist’s toolbox and augmented and refined it somewhat. Today epidemiologists use the Epidemiological Triangle (see figure 3.1) along with the standard scientific method. The Epidemiological Triangle is the traditional model of infectious disease causation. Simply, by using the triangle, Epidemiologists have added a few more important tools to the scientists’ toolbox. As shown in figure 3.1, the triangle has three major components: an external agent, a susceptible host, and an environment that brings the host and agent together. The triangle also includes time. In this model, the environment influences the agent, the host, and the route of transmission of the agent from the source to the host.
Figure 3.1 The Epidemiological Triangle.
Agent—“What”
Agent originally referred to an infectious (pathogenic) microorganism—virus, bacteria (such as Streptococcus and Staphylococcus), fungi (mold and mushrooms), and protozoa (a type of parasite such as Giardia and Cryptosporida). Simply, the agent is cause of the disease. Most people call agents “germs.” Disease agents must be present for disease to occur. That is, they are necessary but not always sufficient to cause disease. When studying the epidemiology of most infectious diseases, the agent is an organism too small to be seen with the naked eye. This is why the germ theory of disease was not formulated before Van Leeuwenhoek refined the microscope—the microbes were simply too small to be seen by the naked eye.
Science, scientific principles, practices, and methodologies that are continually being added to scientists’ toolboxes have brought us a long way forward in our constant battle against infectious disease. We have a long way to go, of course. Until we conquer heart disease, cancer, diabetes, MS, HIV, Alzheimer’s, Parkinson’s, and many other dreaded diseases, we have only scratched the surface in our ongoing battle against disease.
In our never-ending battle against infectious disease, we have had breakthroughs in medical science that make all of our lives better. The 1950s cure for polio is probably the most memorable and relatively current example of a medical advance that has reduced much suffering and pain, and no doubt has saved countless lives.
It is interesting to note that even the most scientific illiterate individual usually sits up and takes notice when some astonishingly new medical finding that will save lives or make life easier to live is announced. Interest is short term, of course, but it is there initially because the discovery has direct and readily visible impact on the individual.
There are a number of scientific facts and occurrences present in our daily lives, however, that very few notice. Newspapers and other media outlets do not provide large swaths of print or broadcast time to science, unless there is some significant finding or cure for a deadly disease. Beyond the significant and attention-grabbing headlines there are several mundane science facts available to us all that are generally ignored; they simply do not have that “reach out and grab you” quality that a new hit song, television show, or movie might have. The point is that when we discuss a topic such as the one we are discussing now—that is the epidemiological triangle and its three factors, agent, environment, and host—most people don’t have a clue or an interest in any of them—it’s the old “science is for scientists only syndrome.”
Of course our mission in this text is to explain science in the simplest way possible and, at the same time, point out why science is important to us all. Whether we want to admit it or not, we all need some background in science to survive and to live life to the fullest, or at least to try to live better. The good news is we do not need to be scientists to understand and appreciate science. Instead, we simply need to be aware of the world around us and its impact on us and our impact on it.
Therefore, when we mention, discuss, and describe the epidemiological triangle and its individual members it has importance to all of us in our daily lives. In order to gain better understanding of the term agent and how it impacts our daily existence, we have included two sidebars relevant to this discussion. In the sidebars we discuss the disease-causing agents Giardia lamblia (Giardia) and Cryptosporida (Crypto). If you have ever hiked in the mountains or woods along various trails in our national parks or other areas, you are probably familiar with Giardia or at least its effects. If you have lived in certain parts of the US when water treatment operations failed or were inadequate, you might be familiar with Crypto. However, as we found out on a recent hiking trip on various trails in Zion National Park, Utah many fellow hikers did not hesitate to stop at a hillside spring and indulge in what appeared to be mountain-fresh spring-fed water as it trickled down and through the rocks.
Whenever we stumbled across hikers who were about to drink from these water sources, we warned them “don’t drink the water!”
Why, you ask? Consider Sidebar 1.
Sidebar 1 Don’t Drink the Water
Giardia (gee-ar-dee-ah) lamblia (also known as hiker’/traveler’s scourge or disease) is a microscopic parasite (protozoan) that can infect warm-blooded animals and humans. Although Giardia was discovered in the 19th century, not until 1981 did the World Health Organization (WHO) classify Giardia as a pathogen. Giardia has an outer shell called a cyst that allows it to survive outside the body for long periods. If viable cysts are ingested, Giardia can cause the illness known as Giardiasis (GEE-are-DYE-uh-sis), an intestinal illness that can cause nausea, anorexia, fever, and severe diarrhea. The symptoms last only for several days, and the body can naturally rid itself of the parasite in one to two months. However, for individuals with weakened immune systems, the body often can’t rid itself of the parasite without medical treatment.
In the United States, Giardia is the most commonly identified pathogen in waterborne disease outbreaks. Contamination of a water supply by Giardia can occur in two ways: (1) by the activity of animals in the watershed area of the water supply; or (2) by the introduction of sewage into the water supply. Wild and domestic animals are major contributors in contaminating water supplies. For example, on the Appalachian, Cascadian, and other well known and well used trails, contraction of Giardiasis is quite common. In Zion National Park, the main contributor of Giardia to the open mountain water supplies are the mule deer which make continuous deposits of feces and urine into these supplies as they traverse the grounds or stop to eat. Studies have also shown that, unlike many other pathogens, Giardia is not host-specific. In short, Giardia cysts excreted by animals can infect and cause illness in humans. Additionally, in several major outbreaks of waterborne diseases, the Giardia cyst source was sewage contaminated water supplies.
Treating the water supply, however, can effectively control waterborne Giardia. Chlorine and ozone are examples of two disinfectants known to effectively kill Giardia cysts. Filtration of the water can also effectively trap and remove the parasite from the water supply. The combination of disinfection and filtration is the most effective water treatment process available today for prevention of Giardia contamination.
In drinking water, Giardia is regulated under the Surface Water Treatment Rule (SWTR). Although the SWTR does not establish a Maximum Contaminant Level (MCL) for Giardia, it does specify treatment requirements to achieve at least 99.9 percent (3-log) removal and/or inactivation of Giardia. This regulation requires that all drinking water systems using surface water or groundwater under the influence of surface water must disinfect and filter the water. The Enhanced Surface Water Treatment Rule (ESWTR), which includes Cryptosporidium and further regulates Giardia, was established in December 1996.
Is Giardia a new disease? The short answer is no. The compound answer is, we do not know how long the parasite has been around, but one thing is certain; it is around. CDC (2009a) points out that during the past 2 decades giardia infection has become recognized as a common cause of waterborne disease in humans in the United States. Giardia can be found worldwide and within every region of the US. Giardia lamblia cysts have been discovered in the U.S. in places as far apart as Estes Park, Colorado (near the Continental Divide); Missoula, Montana; Wilkes-Barre, Scranton, and Hazleton, Pennsylvania; and Pittsfield and Lawrence, Massachusetts, just to name a few.
Giardiasis is characterized by intestinal symptoms that usually last one week or more and may be accompanied by one or more of the following: diarrhea, abdominal cramps, bloating, flatulence, fatigue, and weight loss. Although vomiting and fever are commonly listed as relatively frequent symptoms, people involved in waterborne outbreaks in the U.S. have not commonly reported them.
Why not? Based on our experience and observation, people who get sick from giardiasis just think it is one of those things that happens every now and then and generally have no idea what caused their illness. This lack of very basic scientific knowledge has made life in the short term quite miserable for those who have ingested protozoan-infested mountain-fed waters. Peoples’ lack of knowledge concerning Giardia prevents them from either avoiding ingesting the water or from using simple treatment methods to avoid contamination such as boiling water or using a small 1-micron filter to filter out the protozoans from the water.
While most Giardia infections persist only for one or two months, some people undergo a more chronic phase, which can follow the acute phase or may become manifest without an antecedent acute illness. Loose stools and increased abdominal gassiness with cramping, flatulence, and burping characterize the chronic phase. Fever is not common, but malaise, fatigue, and depression may ensue (Weller 1985). For a small number of people, the persistence of infection is associated with the development of marked malabsorption and weight loss (Weller 1985). Similarly, lactose (milk) intolerance can be a problem for some people. This can develop coincidentally with the infection or be aggravated by it, causing an increase in intestinal symptoms after ingestion of milk products.
Some people may have several of these symptoms without evidence of diarrhea or have only sporadic episodes of diarrhea every three or four days. Still others may not have any symptoms at all. Therefore, the problem may not be whether you are infected with the parasite or not, but how harmoniously you both can live together, or, how to get rid of the parasite (either spontaneously or by treatment) when the harmony does not exist or is lost.
Note: Three prescription drugs are available in the United States to treat giardiasis: quinacrine, metronidazole, and furazolidone. In a recent review of drug trials in which the efficacies of these drugs were compared, quinacrine produced a cure in 93 percent of patients, metronidazole cured 92 percent, and furazolidone cured about 84 percent of patients (Davidson 1984).
As mentioned, giardiasis occurs across the world. Giardiasis ranks among the top 20 infectious diseases that cause the greatest morbidity in Africa, Asia, and Latin America; it has been estimated that about two million infections occur per year in these regions (Walsh 1981). In the U.S., Giardia is the parasite most commonly identified in stool specimens submitted to state laboratories for parasitologic examination. During a three-year period, approximately 4 percent of one million stool specimens submitted to state laboratories tested positive for Giardia (CDC 1979). Other surveys have demonstrated Giardia prevalence rates ranging from 1 to 20 percent, depending on the location and ages of persons studied. People who are at highest risk for acquiring Giardia infection in the U.S. may be placed into five major categories:
1. People in cities whose drinking water originates from streams or rivers, and whose water treatment process does not include filtration, or where filtration is ineffective because of malfunctioning equipment
2. Hikers/campers/outdoor people
3. International travelers
4. Children who attend day-care centers, day-care center staff, and parents and siblings of children infected in day-care centers.
5. Homosexual men
People in categories 1, 2, and 3 have in common the same general source of infection, i.e., they acquire Giardia from fecally contaminated drinking water. The city resident usually becomes infected because the municipal water treatment process does not include the filter necessary to physically remove the parasite from the water. The number of people in the U.S. at risk (i.e., the number who receive municipal drinking water from unfiltered surface water) is estimated to be 20 million. International travelers may also acquire the parasite from improperly treated municipal waters in cities or villages in other parts of the world, particularly in developing countries.
In Eurasia, only travelers to Leningrad appear to be at increased risk. In prospective studies, 88 percent of U.S. and 35 percent of Finnish travelers to Leningrad who had negative stool tests for Giardia on departure to the Soviet Union developed symptoms of giardiasis and tested positive for Giardia after they returned home (Brodsky et al. 1974). With the exception of visitors to Leningrad, however, Giardia has not been implicated as a major cause of traveler’s diarrhea—it has been detected in fewer than 2 percent of travelers who develop diarrhea. However, hikers and campers risk infection every time they drink untreated raw water from a stream or river.
Persons in categories 4 and 5 become exposed through more direct contact with the feces of an infected child (day-care center-associated cases), or through direct or indirect anal-oral sexual practices in the case of homosexual men.
Although community waterborne outbreaks of giardiasis have received the greatest publicity in the U.S. during the past decade, day-care exposure has been the most likely source of infection in about half of the Giardia cases discussed with the staff of the Centers for Disease Control over a three-year period. Numerous outbreaks of Giardia in day-care centers have been reported in recent years. Infection rates for children in day-care center outbreaks range from 21 to 44 percent in the U.S. and from 8 to 27 percent in Canada (Black et al. 1981). The highest infection rates are usually observed in children who wear diapers (one to three years of age). In a study of 18 randomly selected day-care centers in Atlanta, 10 percent of diapered children were found infected (CDC Unpublished). Transmission from this age group to older children, day-care staff, and household contacts is also common. About 20 percent of parents, caring for an infected child become infected.
Local health officials, managers of water utility companies, and the general public need to realize that municipal drinking water is not the sole source of Giardia infection. Armed with this knowledge, they are less likely to make a quick (and sometimes wrong) assumption that a cluster of recently diagnosed cases in a city is related to municipal drinking water. Of course, drinking water must not be ruled out as a source of infection when a larger than expected number of cases is recognized in a community, but the possibility that the cases are associated with a day-care center outbreak, drinking untreated stream water, or international travel should also be entertained.
Sidebar 2 Make Sure the Water Is Treated Properly before Drinking It
Ernest E. Tyzzer first described the protozoan parasite Cryptosporidium in 1907. Tyzzer frequently found a parasite in the gastric glands of laboratory mice. He identified the parasite as a sporozoan, but of uncertain taxonomic status; he named it Cryptosporidium muris. Later, in 1910, after more detailed study, he proposed Cryptosporidium as a new genus and C. muris as the type of species. Amazingly, except for developmental stages, Tyzzer’s original description of the life cycle was later confirmed by electron microscopy. Later, in 1912, Tyzzer described a new species, Cryptosporidium parvum (Tyzzer 1912).
For almost 50 years, Tyzzer’s discovery of the genus Cryptosporidium (because it appeared to be of no medical or economic importance) remained (like himself) relatively obscure. However, slight rumblings of the genus’ importance were felt in the medical community when Slavin (1955) wrote about a new species, Cryptosporidium melagridis, associated with illness and death in turkeys. Interest remained slight even when Cryptosporidium was found to be associated with bovine diarrhea (Panciera 1971).
Not until 1982 did worldwide interest focus in on the study of organisms in the genus Cryptosporidium. During this period, the medical community and other interested parties were beginning to attempt a full-scale, frantic effort to find out as much as possible about Acquired Immune Deficiency Syndrome (AIDS). The CDC reported that 21 AIDS-infected males from six large cities in the U.S. had severe protracted diarrhea caused by Cryptosporidium.
However, it was in 1993 when the “bug—the pernicious parasite Cryptosporidium—made [itself and] Milwaukee famous (Mayo Foundation 1996).”
Note: The Cryptosporidium outbreak in Milwaukee caused the deaths of 100 people—the largest episode of waterborne disease in the U.S. in the 70 years since health officials began tracking such outbreaks.
Today we know that the massive waterborne outbreak in Milwaukee (more than 400,000 persons developed acute and often prolonged diarrhea or other gastrointestinal symptoms) increased interest in Cryptosporidium at an exponential level. The Milwaukee Incident spurred both public interest and the interest of public health agencies, agricultural agencies and groups, environmental agencies and groups, and suppliers of drinking water. This increase in interest level and concern has spurred on new studies of Cryptosporidium with emphasis on developing methods for recovery, detection, prevention, and treatment (Fayer et al. 1997).
The U.S. Environmental Protection Agency (EPA) has become particularly interested in this “new” pathogen. The similarity to Giardia lamblia and the need to provide an efficient conventional water treatment capable of eliminating viruses at the same time forced the USEPA to regulate the surface water supplies in particular. The proposed “Enhanced Surface Water Treatment Rule” (ESWTR) included regulations from watershed protection to specialized operation of treatment plants (certification of operators and state overview) and effective chlorination. Protection against Cryptosporidium included control of waterborne pathogens such as Giardia and viruses (DeZuane 1997).
Cryptosporidium can be prevented by proper water treatment protocols. In the wild, when it becomes necessary to drink natural, untreated water, it is essential that the water be boiled or treated with an iodine filter, or a 1-micro filter. In our opinion, awareness is the most important point. Knowing a little about the science involved with possible contaminants in our water supply is not only a good idea but also important to maintaining good health.
In the preceding sidebars we have described two of an unknown number of potential infectious agents that make up the epidemiologic triangle. It is also important, however, to point out that the agents that makeup the epidemiologic triangle do not all have to be infectious agents. With time and practice, epidemiology has been applied to noninfectious conditions; the concept of an agent in this model had been broadened to include chemical and physical causes of disease. These include chemical contaminants, such as the l-tryptophan (L-TRIP-toe-fan) contaminant responsible for eosinophilia-myalgia syndrome (EMS; an incurable and sometimes fatal flu-like neurological condition), and physical forces, such as repetitive motion forces associated with carpal tunnel syndrome. On the other hand, it should also be pointed out that this model does not work well for some noninfectious diseases, because it is not always clear whether a particular factor should be classified as an agent or as an environmental factor.
The Host—“Who”
Hosts are part of the epidemiological triangle (see figure 3.1); they are organisms, usually humans or animals, which are exposed to and harbor a disease. Host factors are intrinsic factors that influence an individual’s exposure, susceptibility, or response to a causative agent. Age, race, sex, socioeconomic status, and behaviors (smoking, drug abuse, lifestyle, sexual practices, contraception, and eating habits) are just some of the many host factors which affect a person’s likelihood of exposure. Age, genetic composition, nutritional and immunological status, anatomic structure, presence of disease of medications, and psychological makeup are some of the host factors which affect a person’s susceptibility and response to an agent.
According to the CDC (2009), the host (a virus or parasite, or a mutual or commensal symbiont—i.e., the living together of unlike organisms) can be the organism that gets sick, as well as any animal carrier (including insects and worms) that may or may not get sick. Although the host may or may not know it has the disease or demonstrate any outward signs of illness, the disease does take lodging from the host. The “host” heading also includes symptoms of the disease. Different people may also have different reactions to the same agent. For example, adults infected with the virus variacella (chickenpox) are more likely than children to develop serious complications. In Giardia, infection occurs in humans, but it is also one of the most common parasites infecting cats, dogs, and birds. Mammalian hosts also include cows, beavers, deer, and sheep.
It is interesting to note that several species of Cryptosporidium were incorrectly named after the host in which they were found; subsequent studies have invalidated many species. Now, eight valid species of Cryptosporidium (see Table 3.1) have been named.
Table 3.1 Valid Named Species of Cryptosporidium (Fayer et al 1997)
|
Species |
Host |
|
C. baileyi |
chicken |
|
C. felis |
domestic cat |
|
C. meleagridis |
turkey |
|
C. murishouse |
house mouse |
|
C. nasorium |
fish |
|
C. parvum |
house mouse |
|
C. serpentis |
corn snake |
|
C. wrairi |
guinea pig |
Upton reports that C. muris infects the gastric glands of laboratory rodents and several other mammalian species, but (even though several texts state otherwise) is not known to infect humans. C. parvum, however, infects the small intestine of an unusually wide range of mammals, including humans, and is the zoonotic species responsible for human cryptosporidiosis. In most mammals, C. parvum is predominately a parasite of neonate (newborn) animals. He points out that even though exceptions occur, older animals generally develop poor infections, even when unexposed previously to the parasite. Humans are the one host that can be seriously infected at any time in their lives, and only previous exposure to the parasite results in either full or partial immunity to challenge infections.
Environment—“Where”
The environment vertex of the epidemiological triangle are extrinsic factors that signify the region, surroundings, or place external to the host that cause or allow the disease to be transmitted. According to the CDC (2009), environmental factors include physical factors such as geology, climate, and physical surroundings (e.g., a nursing home, hospital); biologic factors such as insects (vectors) that transmit the agent; and socioeconomic factors such as crowding, sanitation, and the availability of health services. As pointed out with cholera, Giardia and Crypto, some diseases flourish in dirty water. Still others, like E. coli, thrive in warm temperatures but are killed by high heat. Other environment factors include the season of the year (in the U.S., the peak flu season is between November and March, for example).
Sidebar 3 Don’t Eat the Spinach, Onions, Beef, or Cookie Dough
The CDC reported several outbreak investigations of Escherichia coli 0157:H7 recently including the following:
2018:
• Multistate Outbreak of E. coli O157:H7 infections linked to romaine lettuce
2017:
• Multistate Outbreak of Shiga toxin-producing Escherichia coli O157:H7 infections linked to I.M. Healthy Brand SoyNut Butter
• Multistate outbreak of shiga toxin-producing Escherichia coli O157:H7 infections linked to leafy greens
2016:
• Multistate outbreak of Shiga toxin-producing Escherichia coli O157 infections linked to alfalfa sprouts produced by Jack & the Green Sprouts
• Multistate outbreak of Shiga toxin-producing Escherichia coli infections linked to flour
• Multistate outbreak of Shiga toxin-producing Escherichia coli O157:H7 infections linked to beef products produced by Adams Farm
As is evident from the list above, it is not only the waterborne diseases that concern scientists (and the rest of us) but also foodborne diseases. The struggle to keep our food supply safe is an ongoing enterprise. We need science and scientists to maintain our food supplies in a safe-to-consume status. However, our first line of defense in preventing the consumption of contaminated foods is ourselves. We must keep informed about food recalls and alerts, and follow these guidelines to prevent food poisoning. This is an area of scientific communication, along with bad water and bad air advisories, where we simply can’t afford to have a failure to communicate and/or to act.
There are several different types of parasites, viruses, molds, and bacteria that can contaminate our food and make us ill. We focus here on Escherichia coli outbreaks because of their prevalence in the news recently. News events detailing the deaths of young children who consumed hamburgers or other fast foods contaminated with Escherichia coli are not pleasant for any of us to read or hear about or suffer through. Escherichia coli (abbreviated E. coli) are a large and diverse group of bacteria. Scientists have determined that most strains are harmless, but others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses. Still other kinds of E. coli are used as markers for water contamination (coliform bacteria)—so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate that water is contaminated. It gets a bit confusing—even to the scientists.
Sidebar 4 Flesh-eating Superbug Killed Father in Just Four Hours
The Daily Mail Reporter (2009) published the above headline in Britain about local citizens facing a “new horror” from a flesh-eating superbug which killed a father within just four hours of his arrival at a hospital with leg pains. The victim had been given painkillers for what doctors thought was arthritis. But when it became apparent that he had the infection, necrotizing facilitis surgeons amputated his left leg in a bid to save him. The account goes on to say that they watched in horror as black areas spread to the man’s abdomen while they were operating. The victim died in short order.
In the above account, the dastardly, deadly culprit that caused this latest flesh-eating episode and the quick and gruesome death of its victim was attributed to MRSA (multidrug-resistant Staphylococcus aureus). The CDC (2009c) estimates the number of people developing a serious MRSA infection (i.e., invasive) in 2005 was about 95,000. Although MRSA remains a major threat, there is some encouraging news. A CDC study showed that MRSA infections are declining. Invasive MRSA infections that began in hospitals declined 54 percent between 2005 and 2011, with 30,800 fewer severe MRSA infections. In addition, the study showed 9,000 fewer deaths in hospital patients in 2011 versus 2005.
Note of Caution: A few years ago we had one of our university environmental health classes study MRSA and its possible contraction points. One of our students who worked in a hospital took swab samples from hospital appliances, beds, and furniture and then cultured them as appropriate. MRSA was detected in various hospital locations (this was not unexpected) but seemed especially prevalent on patient’s privacy curtains. The lesson she derived from her study and experiments? Keep away from and do not touch hospital privacy curtains.
We have discussed a few of the known environments of various disease agents that scientists are constantly doing battle with in the struggle to eradicate or to combat the disease with new medicines and/or sanitary procedures that hopefully will ensure our continued good health and well-being.
Time
In the center of figure 3.1 is time. Most infectious diseases have an incubation period—the time between when the host is infected and when disease symptoms occur. Or, time may describe the duration of the illness or the amount of time a person can be sick before death or recovery occurs. Time also describes the period from an infection to the threshold of an epidemic for a population (CDC 2008).
Epidemiological Triangle: A Practical Application
In communicating the “Why?” in science, the benefits of science, the practicality of science, and the absolute need for science it is often best to use a practical example that everyone can identify with. This is exactly what we do in this section. In doing so, we assume that most people have attended a picnic or two in their lifetimes. For those who have not enjoyed this experience they must certainly know people who have. The point is we have included sidebar 5, a CDC (2009d) classroom training scenario, fashioned by experts and presented in down-to-earth, everyday, plain language (scientific jargon reduced to the absolute minimum), designed for teachers’ use in teaching students the importance of science and the everyday benefits that can be garnered from scientific analysis.
Bad
Poisoned Picnic
The picnic started at 6:00 p.m. Tuesday evening at Grand City Park. The park is located by the Grand River and contains several gazebos and picnic areas. The administration and faculty of Grand City Middle School organized the picnic as a relaxing event to be held before the faculty meeting. Many faculty and staff brought members of their family.
Mrs. Smith and Ms. Johnston arrived at 5:30 to set up. Mr. Albert arrived next to set up the grill. He brought his grill from home and had to take a few minutes to clean it off because it had not been used since last summer. Mr. Drake arrived next, after having bought the hamburgers at the supermarket. After the charcoal was lit and aluminum foil was placed over the grills, Mr. Albert began to cook.
At 5:55, Mrs. Smith realized that there was only one serving spoon. At this point, she left to get some more spoons. The other teachers waited for a while, but finally decided to start eating at about 6:20.
When all of the food arrived there was a full menu that included baked beans, chicken, ham, green bean casserole, tuna casserole, cherry pie, pudding, potato salad, macaroni salad, corn, and hamburgers. Drinks included soda, water, coffee, and tea.
Mr. Drake was first through the line. He tried:
• green bean casserole
• ham
• a hamburger
Ms. Cummings was next. She ate:
• potato salad
• ham
• a hamburger
The third person through the line was Mr. Carlson. He ate:
• green bean casserole
• potato salad
• a hamburger
Mrs. Albert was nest in line. She sampled:
• potato salad
• a hamburger
• cherry pie
At this point, Mrs. Smith returned with more serving spoons. Mrs. Bell came at the same time. She was a little late because she had to be sure that her chicken was done.
Mrs. Wolfe went through the line next. She ate:
• green bean casserole
• chicken
• a hamburger
• pudding
Next was Mr. Lewis, who ate:
• baked beans
• green bean casserole
• macaroni salad
• corn
The line became a little unorganized at this point and it is not clear who went through next. Mrs. Smith and Ms. Johnston were two of the last people through since they helped to serve.
Mrs. Smith ate:
• green bean casserole
• potato salad
• a hamburger
• pudding
Others in attendance included Mr. Harvey, Ms. Jackson, Mr. Dooley, Mrs. Jones, and Mrs. Darwin. A lot of the guests said they could not remember exactly what they ate, but Mr. Harvey, Mr. Dooley, Mrs. Jones, and Mrs. Bell all had hamburgers, baked beans, and macaroni salad.
Ms. Jackson and Mrs. Darwin had ham, baked beans, corn, and some pudding for desert.
Ms. Cain, Mrs. Williams, Dr. Oakton, Mrs. Corning, and Mrs. Reid have not yet been interviewed. Some other staff members arrived just in time for the faculty presentations, which started at 7:45. These included Mrs. Robinson, Mrs. Brown, and Mrs. Wright.
Some of the faculty and staff walked around while they ate but most sat in one of the gazebos. The presentations were held in the main gazebo which was a relief for some of the faculty because it seemed to be one of the few places free of duck droppings.
Even during the meeting, some of the kids chased ducks with their water guns. These kids never seemed to run out of water because the guns held almost a gallon each, but even if they did run out, they quickly refilled them from the river. Just about everyone at the picnic except for those that came only for the meeting were soaked. Since it was a hot day, the only time anyone seemed to mind the soaking was when one of the kids missed their intended target and almost put out the grill. After this incident, which happened about 6:10, the kids stayed away from the main gazebo where the food was located, and turned their attention to the ducks and teachers walking around.
Grand City officials were alarmed by the illnesses and deaths that seemed to be associated with the event. They have promised a full investigation. Even the wastewater treatment plant just a few hundred yards up the river will have to submit a report on their procedures for water treatment. This is the first time anything like this has happened at the park and officials want to be sure that it does not happen again.
Park managers said that most of the symptoms such as dehydration, stomach cramps, nausea, and vomiting indicate some type of food poisoning. However, at this point they cannot be certain.
You are now part of a team of epidemiologists that has been called in to get to the bottom of this mystery. You will need to identify the cause of the disease and prevent any further outbreaks. Time is of the essence. The first thing you will want to do is meet with your team members and outline the information you have been given and then decide what additional information you need. Grand City authorities have promised complete cooperation in this matter. Good luck!
Data Collection
The first order of business for the team of epidemiologists is to determine the goal of their investigation and to compile data related to the picnic. The goal is to determine the cause of the mysterious disease and how to prevent future outbreaks. Item #1, the picnic menu, and other collected items are shown below.
Item #1: Grand City Middle School Faculty Picnic Menu
Baked beans: Simply purchased two large cans of baked beans and heated on stove top to boiling.
Pudding: Mixed four packets of chocolate pudding with four cups of milk. Heated and then refrigerated.
Chicken: Baked chicken legs for 1 hour.
Ham: Baked ham for 2 hours 30 minutes until thermometer read 150 degrees for 20 minutes.
Green bean casserole: Cracker crust covered with two cans of cream of mushroom soup and two jars of green beans. Topped with 2 cans of small onions. Baked for 20 to 25 minutes to warm.
Potato salad: One jar of salad dressing (mayonnaise), assorted diced vegetables, 2 tablespoons sugar, ½ cup mustard, 6 cups diced and cooked potatoes.
Macaroni salad: One box elbow macaroni, 3 tablespoons of mustard, one jar salad dressing (mayonnaise), various diced vegetables.
Tuna casserole: Cracker crust, 3 cans tuna, one can cream of mushroom soup, one can cream of chicken soup. Mixed and topped with parmesan cheese topping.
Hamburgers: Purchased at the supermarket just before the picnic (receipt showed time was 12:25).
Corn: 2 large cans of corn heated to simmering.
Cherry pie: Mountain top cherry pie, baked 40 minutes, pre-made.
Pause 1: It’s Got to be the Potato Salad or Macaroni Salad!
We feel it is important to pause for a moment. We want to point out to readers that we have presented this particular case to undergrad environmental health students in a few of our 300 level college courses for several years. We know this is the right place to pause in our presentation because right after we introduce the above picnic menu to our students many of their faces light up and beam that look of knowing the answers. We are used to this occurrence and always cease our presentation to allow the students the chance to comment on what they think. Invariably their statements seem to relate the following: “Ah, they all got sick because of the potato and/or macaroni salad . . . it was probably the mayonnaise that poisoned ‘em.” We allow the students to banter round and round with their statements without our interjection. But as with all bubbles that eventually burst into nothingness, the time soon arrives to burst a few bubbles and put the students back on the correct scientific approach to finding the picnic poison.
We explain that commercially prepared mayonnaise gets a bad rap when it comes to making picnickers sick from eating potato salad and/or macaroni salad. A commercially made jar of mayonnaise is set with a pH level point that bacteria can’t survive. The pH level makes mayonnaise safe to eat even if not refrigerated.
When people become sick from eating these salads, the causal factors are related to how long the salads have sat in the sun, along with the potatoes and onions. Bacteria have never found a freshly cut potato or onion that they did not immediately attack. Bacteria can’t resist either one and it is these potatoes and onions that are the culprits—not mayonnaise. However, in this case the potato and macaroni salads are not the culprits.
Item #2: Poisoned Picnic Faculty Information Cards
Mrs. Cain
Brought plates and cups to the picnic. Had chicken, potato salad, pudding, green bean casserole. Become sick Tuesday evening. Symptoms included: nausea, vomiting, and dizziness.
Mr. Lewis
Organized a game of volleyball set up by the gazebo. The players were a favorite target for the water guns!! The only foul was when Mrs. Cain stepped on a duck going after the ball. Mr. Lewis became ill Tuesday evening. He was treated and released from the hospital Wednesday morning.
Mrs. Williams
Recovering. Became ill Tuesday night and was rushed to the hospital by her husband. Her son enjoyed his water gun, dousing teachers with river water. She loved the burgers made by Mr. Albert. She also tried some green bean casserole, chicken, and pudding. Her son did not become ill.
Mrs. Reid
Sampled a little bit of everything. She became ill Tuesday night and finally went to the hospital Wednesday morning. She complained of stomach cramps and nausea. Doctors quickly began an IV to help replenish lost fluids. She briefly went into a coma and then slowly recovered.
Dr. Oakton
Recovering. Had a great time except for when she stepped in duck droppings, which seemed to be everywhere. She didn’t even mind being soaked. She tried a little bit of everything to eat.
Mr. Albert
Mr. Albert took control of the grill. Mr. Drake soon showed up with the hamburger meat and started making the burgers. Mr. Albert had some potato salad, green bean casserole, a hamburger, and pudding for desert. Mr. Albert became ill, suffering from numbness, disorientation, nausea, and vomiting. He was treated and released after several days in the hospital.
Mrs. Corning
Arrived late, just in time to grab a burger and some green bean casserole. Most of the utensils and the food were already put away. She became ill Wednesday morning and had to leave work around 8:30. She suffered from nausea, dizziness, and was so disoriented that she could not drive home.
Mrs. Smith
She arrived early with her son and helped to set up for the picnic. After many of the staff arrived, she realized that there was only one serving spoon so she went home to get some more. She returned 30 minutes later with spoons (after several faculty had gone through the line) to find her son chasing ducks with water guns. Both Mrs. Smith and her son became ill.
Mrs. Johnston
Helped to set up for the picnic. She had a hamburger, baked beans, pudding, and corn. She and several other teachers spent their time sitting in one of the gazebos talking and watching the children run after the ducks. Mrs. Johnston is lactose intolerant. She became ill just a couple of hours after the picnic, suffering from severe stomach pains. She went to bed and recovered overnight.
Mrs. Albert
Complained of stomach cramps early Tuesday night. Her condition to continued to worsen until she finally had to be taken to the hospital. She was given massive doses of antibiotics. Her condition became worse as symptoms began to include vomiting and disorientation. She soon found out that she could remember much about the picnic. After some time, her condition improved.
Item #3 consisted of specific, additional information about the poisoned picnic event.
Item #3: Picnic Information Card
It was determined that there was only one burger on the grill when it was soaked. Mr. Albert decided to throw it away because he had to lift up the grill and add more charcoal. Many times he would walk away from the grill to talk to someone and return to some very well done burgers. No one seemed to mind, that’s the way they wanted them.
It was also learned that the wastewater treatment plant performed several tests on the water coming from the plant (effluent). The effluent was virtually void of any bacteria. The plant was doing a good job. They also did tests on the water around the park and found no notable bacterial contamination.
The epidemiological team obtained item 4, the pathology reports on victims.
Item #4: Pathology Report
Victim: Mrs. Wolfe
Admitted to hospital suffering from abdominal pain and vomiting. Began diagnostic tests but patient’s condition deteriorated. Death due to respiratory and heart failure. Time of death: 3:30 a.m.
Victim: Mr. Carlson
Paramedic response to home. Pronounced dead on arrival. Attempts to revive failed. Time of death: 11:30 p.m
Victim: Mr. Drake
Admitted to hospital suffering from abdominal pain, headache, and paralysis of extremities. Lapsed into shock. Pulmonary failure followed. Time of death: 2:30 a.m.
Victim: Mrs. Cummings
Admitted to hospital suffering paralysis. Unable to communicate to hospital staff. Died of heart and respiratory failure. Time of death: 1:20 a.m.
Item #5: Round Up the Usual Suspects
Because the epidemiological investigative team determined the culprit in the poisoned picnic episode was likely food poisoning, they listed specific disease-causing microbes that could be responsible. The suspect list is provided as follows:
Table 3.2 Poisoned Picnic: List of Suspect Disease-Causing Microbes
From the toxin suspect list shown above and the information and clues gathered from other sources the team was able to select the correct food item and toxin responsible for the incident. The results of their findings are detailed in the incident explanation below.
Pause 2: The Culprit Identified?
Before presenting the poisoned picnic team’s findings we thought we would ask: Have you identified the food and the toxin? Let’s see if your decision matches the team’s findings.
Poisoned Picnic: Incident Explanation
In determining the food item and correct toxin that caused the poisoned picnic event, the investigation team pieced together the following clues from a variety of sources:
• The opening information states that there was only one serving spoon when the teachers began going through the line. Moreover, the first person through the line had green bean casserole. That person was one of the four fatalities. The next person through the line was also a fatality. This person did not eat green bean casserole. But the toxin was on the serving spoon after being used for the casserole and then for the potato salad. The second person through the line got it from the spoon! After this, the other serving spoons arrived and the cross contamination soon ended.
• Team members realized that everyone that had the green bean casserole contracted the illness. Two people became ill, one of whom died, that did not have the green bean casserole. The second person through the line, as stated above, contracted the disease from the serving spoon. The other person was lactose intolerant and became ill because of the pudding, which was made with milk.
• From the list of usual suspects, team members were able to link the symptoms of the disease to botulism. From this and other research, team members knew that botulism can come from improperly canned vegetables. The menu states that the green bean casserole was made using canned green beans. Botulism is easily destroyed by high heat. However, the menu also states that the casserole was only heated to warm. This would not have provided enough heat to destroy the toxin.
• In addition to identifying the cause of the disease, team members were also to outline a strategy to prevent future outbreaks of the disease. Because this outbreak was due to food poisoning, team members realized that they needed to educate the teachers and students and parents about proper food handling techniques. For this specific contaminant, information should include inspection of canned foods for bulges (a result of gas buildup from growth of the bacteria), and also stress the importance of sufficient heat to destroy the toxin. Other general information should include cleanliness in food preparation areas, washing of hands, and the use of clean utensils in food preparation. This information could be presented in the form of a brochure or a school auditorium skit that would be broadcast on CCTV, local television, or radio stations.
Final Pause
So, did you determine that the green bean casserole was the bad food, that the spoon was the source of cross-contamination, and that the deadly toxin was Clostridium botulinum? If so, great! If not, no problem. The point is the poisoned picnic event demonstrates the need for a step-by-step approach based on actual facts in determining causal factors related to an event such as this one.
For those of you who immediately jumped on the potato salad or macaroni salad (laced with copious amounts of mayonnaise, of course) as being the bad food, as mentioned, you are not alone in your assumptions. And this is the point about the need for science and the scientists’ toolbox. Investigative opinions should be based on facts and good science—peer-reviewed and verified facts and the practice of good science only, please!
Ugly
When the Animas River Became a Yellow Boy2
The Day: Wednesday
The Date: August 5, 2015
The Place: Near Silverton, Colorado
The Event: Gold King Mine Spill
Surface Water Body Affected: Cement Creek, Animas, San Juan and Colorado River
Watershed: Includes six U.S. states (Colorado, Utah, New Mexico, Arizona, Nevada, California)
Sources and References: US EPA(a), 2015. United States Environmental Protection Agency, Frequent Questions Related to Gold King Mine Response. United States Environmental Protection Agency, Gold King Mine Incident: Preliminary Analytical Data Upper Animas River (page 6), 15 August 2015.
The 411 on the Gold King Mine Spill
A United States Environmental Protection Agency (US EPA) mine site investigation of the abandoned Gold King Mine above the old adit (a mine tunnel) took place to:
• assess the ongoing water releases from the mine
• treat mine water
• assess the feasibility of further mine remediation
During this investigation, a heavy equipment disturbed loose material around a soil “plug” at the mine entrance, spilling about three million gallons of pressurized water stored behind the collapsed material into Cement Creek, a tributary of the Animas River.
The spill volume associated with the release on August 5 was calculated to be approximately three million gallons based on flow rates. Current discharge rates (November 5, 2015) from the mine are averaging around 600 gallons per minute. For context, it is important to point out, that there are multiple mines along the upper Animas, and historically there has been considerable discharge at each mine site. The Red and Bonita Mine, just below Gold King Mine, is currently discharging about 300 gallons per minute.
One of the results and striking features (quite apparent to all who witnessed it) of the Gold King Mine spill was the color change to the Cement Creek and Animas River, and to a lesser degree, downstream almost to the San Juan River. The iron from the red-orange acid mine drainage settled into the water, turning it yellow. Old-time goldpanners and other sluice miners referred to this as “yellow boy.” As more water is mixed in (dilution is the solution to pollution, according to that mythical hero Hercules, who I argue might have been the world’s first environmental engineer), iron and other metals become even more dilute and/or get attached to solids (sediments), causing them to drop out of the water (sink) and settle into river bottom sediments, and the water color returns to normal.
But, and this is the gist of this text, what appears normal in surface water bodies (or any environmental medium) may not be normal because, as in the case of the Animas River and thousands of other polluted streams, what we are able to see at the surface does not in any way certify the quality of the water contained within the water body.
Uglier
Flint by Another Name Might be Lead
If it were not so serious and potentially health affecting, or so life-threatening and so defining of the double-D syndrome (i.e., Double-D = disgusting and disturbing), the recent reports of excessive lead contamination in Flint, Michigan’s potable water supply might be labeled a comedy of errors, comedy of stupidity, and/or a comedy of dysfunctional management. But, again, health affecting, life-threatening and/or dysfunctional management occurrences are nothing to laugh about; they are no comedy of errors; they make up a laundry list of errors for sure, but none are laughable.
With regard to the lead-contaminated tap water (running water, city water, municipal water, etc.) event in Flint, Michigan, this was nothing new. Lead, regarded by the ancients as the father of all metals, has been around forever and lead contaminated drinking water, wine, and other sprits is as old as humankind. In addition to describing lead as the father of all metals, ancients also associated it with the deity Saturn, the ghoulish titan who devoured his own young (US EPA, 2016). In its most specific meaning, the very word “saturnine,” applies to an individual whose temperament has become uniformly gloomy, cynical, and taciturn (a fancy word meaning cold and aloof) as the results of lead intoxication.
In ancient times, lead was available for anyone’s use. That is, to a limited degree, lead products were available to even the poorest proletarian (another fancy word meaning blue-collar type). But only the chosen few at the top of the social totem pole were able to regularly indulge their insatiable appetite for lead-containing products. For example, lead was a key component in face powders, rouges, and mascaras; the pigment in many paints (“crazy as a painter” was an ancient catch phrase rooted in the demented behavior of lead-poisoned painters; for those who have traveled down the rabbit hole you may remember mad as a hatter, or the Mad Hatter, but that was the result of mercury poisoning and not lead). It was also used as a nifty spermicide for informal birth control; the ideal “cold” metal for the use in the manufacture of chastity belts, a sweet and sour condiment for seasoning and adulterating food, and a wine preservative perfect for stopping fermentation of inferior vintages. Additionally, it was also used as the malleable and inexpensive ingredient in pewter cups, plates, pitchers, pots and pans, and other household artifacts; the basic component of lead coins; and a partial ingredient in debased bronze or brass coins as well as counterfeit silver and gold coins.
It is interesting to note, and germane to our discussion of Flint’s lead-contaminated water conveyance system, that it was lead’s suitability as inexpensive and reliable piping of the vast network plumbing that kept Rome and the provincial cities of the Roman Empire supplied with water. Moreover, the very word “plumbing” comes from the Latin world for lead, plumbum. The lead pipes that were the vital arteries of ancient Rome were forged by smithies whose patron saint, Vulcan, exhibited several of the symptoms of advanced lead poisoning: lameness, pallor, and wizened (i.e., wrinkled and aged) expression (US EPA, 2016).
Fast forwarding to the present, over the centuries and the countless numbers of disabled and dead humans as a direct result of lead contamination, it is important to note, that not all lead contamination over the centuries was the result of drinking lead-contaminated water. However, our focus here is on drinking water and the debacle of Flint, Michigan’s lead-contaminated drinking water. To gain understanding of what happened in Flint; that is, to comprehend the sequence of events that led up to the drinking water tragedy, a timeline of key events is provided in the following:
Note: The following information is based on the authors’ research and personal communications with various knowledgeable experts.
Note: Lead in water is measured in terms of parts per billion (ppb). If a test comes back with lead levels higher than 15 ppb, the EPA recommends that homeowners and municipalities take steps to reduce that level, like updating pipes and putting anti-corrosive elements in the water when appropriate. But 15 ppb is a regulatory measure, not a public health one. Researchers stress that there is no 100 percent “safe” level of lead in drinking water, only acceptable levels. Even levels as low as 5 ppb can be a cause for concern.
|
Date |
Event |
|
2006 |
Studies regarding Genesee County’s long-term water needs indicate that Flint River water can be safely treated but that it does not have enough capacity for permanent use. |
|
March 25, 2013 |
Flint city council votes 7-1 to leave Detroit Water and Sewage Department (DWSD) and go to Karegnondi Water Authority (KWA) as its water source. |
|
June 2013 |
City of Flint decides to use the Flint River as a water source. |
|
April 25, 1914 |
Flint begins using the Flint River as interim water source. |
|
July 2014 |
Flint begins first six-month monitoring period for lead and copper. |
|
January 1, 2015 |
Flint conducts second sixth month monitoring period for lead and copper. |
|
January 12, 2015 |
DWSD offers to reconnect to Flint and waive $4 million connection fee. |
|
January 29, 2015 |
Flint declines DWSD offer to reconnect to Detroit water supply. |
|
February 3, 2015 |
Governor Snyder awards Flint $2 million to find leaks and replace wastewater incinerator. |
|
February 26, 2015 |
EPA and Department of Environmental Quality (DEQ) discuss high levels of lead found in water. |
|
February 27, 2015 |
DEQ states in email to EPA that Flint water treatment plant has an “optimized corrosion control program” after EPA inquires about treatment. |
|
March 12, 2015 |
Flint water consultant issues report that water meets state and federal standards. Does not report specifically on lead. |
|
March 30, 2015 |
DEQ notifies Flint of results of the first six-month lead and copper monitoring period from July 1, 2014 to December 31, 2014 showing 6 ppb. |
And the beat goes on . . . so they say . . . currently Michigan is doing whatever is necessary to mitigate the Flint lead-contaminated drinking water crisis. Properly treating influent at the waterworks is the first and main step. The water should be treated with a corrosion inhibitor (a chemical sequestrant; Latin, meaning to withdraw from use) such as sodium hexametaphosphate. This inhibitor lines the pipes so nothing in the water can react with the pipes. It should be pointed out, however, that any chemical treatment procedure added at this point in the Flint waterworks treatment routine may be too little too late. The ultimate fix to the problem is to replace the aging lead piping with synthetic piping materials.
|
April 24, 2015 |
DEQ staff indicates to EPA no corrosion control treatment in place. |
|
Late May 2015 |
Emails between EPA and DEQ show concern over three close houses. |
|
July 2, 2015 |
EPA region percent administrator tells Flint mayor “it would be premature to draw any conclusions” based on leaked internal EPA memo regarding lead. |
|
July 21, 2015 |
EPA and DEQ discuss the requirement for corrosion control optimization of drinking water from Flint River. |
|
July 22, 2015 |
Governor Snyder’s Chief of Staff emails DHHS director stating community concerns about lead in the water. Chief of Staff asks about Flint water test results, blood testing, and the state’s response. |
|
August 17, 2015 |
Based on July results showing lead levels at 11 ppb from the second six-month testing period from January 1, 2015 to June 30, 2015 Flint is instructed to optimize corrosion control. |
|
August 23, 2015 |
Virginia Tech researcher raises concerns about corrosion and lead. Notified DEQ that he will be studying Flint’s water quality issues. |
|
September 2, 2015 |
Virginia Tech researcher communicates that the corrosiveness of Flint water is causing lead to leach into residents’ water through pipes. |
|
September 2015 |
DEQ disputes Virginia Tech researchers test results and conclusions about corrosion and lead leaching. |
|
September 28, 2015 |
DEQ and DHHS Directors provide briefing to Gov. Snyder on potential scope and magnitude of the issue. DHHS continues to review blood level tests. |
|
October 1, 2015 |
DHHS confirms lead problem. City of Flint urges residents not to drink water. |
|
October 2, 2015 |
Governor releases 10-point plan to address water system, $1 million for water filters, and anticorrosion treatment. |
|
October 8, 2015 |
Governor announces plant to reconnect to Detroit water and Flint develops the plan. |
|
October 15, 2015 |
Governor Snyder signs supplemental appropriation with $9.35 million to assist Flint in reconnecting to DWSD. |
|
October 19, 2015 |
DEQ director states: “Staff made a mistake while working with the City of Flint. Simply stated, staff employed a federal corrosion control protocol they believed was appropriate and it was not.” |
|
November 3, 2015 |
The EPA indicates differing possible interpretations of the Lead and Cooper Rule (LCR) with respect to how the LCR’s optimal corrosion control treatment procedures apply to this situation (new water source/new water treatment). |
|
December 9, 2015 |
Flint begins to add additional corrosion controls. |
|
December 14, 2015 |
City of Flint declares emergency. |
|
December 29, 2015 |
Governor Snyder takes action on initial findings from Flint Water Task Forces, DEQ Director and Communications Director resign. |
|
December 30, 2015 |
Governor Snyder taps new director to guide DEQ though leadership transition. |
|
January 4, 2016 |
Genesee County Commission votes to declare emergency. |
|
January 5, 2016 |
Governor Snyder declares emergency for Genesee County, activating the State Emergency Operations center. |
|
January 8, 2016 |
Governor Snyder and Flint mayor meet to discuss collaboration. |
|
January 9, 2016 |
Emergency Management Division announces water resource sites established in Flint with bottled water, filters, and testing kit. |
|
January 11, 2016 |
Governor Snyder signs Executive Order to create the Flint Water Interagency Coordinating Committee to work on long-term solutions to the Flint water situation. |
|
January 12, 2016 |
Governor requests FEMA’s assistance and activates Michigan National Guard to help with water resources distribution. |
|
January 14, 2016 |
Governor requests presidential declaration of major disaster and emergency and requests federal aid. |
|
January 16, 2016 |
The president approves declaration of emergency and request for federal aid. The president denies request for a declaration of major disaster. |
Lessons-learned: The Flint, Michigan, lead-contaminated drinking water incident is now well documented. With time many lessons will be learned because of this event. A couple of effects seem certain; first, those who consumed the contaminated water may have irreparable harm to their health; secondly, when humans make decisions that prove to be mistakes, we want to determine the source of those mistakes.
The bottom line: The Flint, Michigan, lead poisoning event was not caused by a failure in science. No, the failure at Flint was due to incompetence, mismanagement, and a failure to communicate. The fact is that water operators in the United States are trained, examined, and licensed to ensure that water at the tap is safe to consume.
Reference: US EPA (2016). Lead Poisoning: A Historical Perspective. Accessed March 1, 2016
From the experience of Flint, Michigan’s lead-contaminated water supply event, we can say that the event mentioned above is possible, could happen, and actually did happen. In the United States of America? Yes. Absolutely. For sure. It is still occurring. This, of course, raises other questions. Are there other Flint, Michigan’s out there contaminating users and waiting to be discovered in the United States? Yes, aging infrastructure is the primary causal factor. Many water distribution systems are more than 100 years old and in dire need of upgrading. The main problem is money. Replacing old and deteriorating distribution systems (piping) in a city or town or county is not cheap. When you inform city managers, city councils, and utility directors that they need to upgrade their water system to the tune of millions of dollars the question from them is “Where do we get the money?” If they contemplate raising funds by making rate payers pay the bill, their political careers or appointed positions will crash and be vacated, quickly. Well, how about the state and feds, can’t they pony up the funds needed to upgrade such a critical infrastructure? Good question; one that is asked quite often, actually. And, they have a quick answer, “Where are we supposed to get the money?” Unless a Flint type event occurs, one that is highly emotional because of potential damage to children and others, and unless you have the media all over the situation, and the politicians pointing fingers here, there, and everywhere except toward them, no action can be expected.
Funding that is hard or impossible to find to retrofit aging municipal water distribution systems is one thing, allowing what occurred in Flint, Michigan, is an entirely different matter. After years of having taught university level undergrad and graduate level environmental health courses, including waterworks operation, and having taught short courses in water and wastewater treatment at Virginia Tech for operators and for those seeking licensure as operators, we were totally surprised by the Flint, Michigan, drinking water dilemma. Water operators, water administrators, waterworks managers, waterworks environmental engineers, and other waterworks personnel know that incoming water (influent) must be sampled and tested for quality. Moreover, during the treatment of water as it flows from unit process to unit process it must be sampled and tested. At the completion of treatment and prior to discharge to the distribution system, the treated water must be sampled and treated again. This sequence of sampling and treating is not just nice to do; it is not just best practices; it is the absolute law of the land. If you do not like the law, then there is still the moral obligation to serve the people who depend on your performance the best and safest drinking water possible. What exactly occurred at Flint may never be precisely revealed. However, one thing is absolutely certain; someone (or several someones) did not do what they were trained and obligated to do. That is, they did not deliver safe drinking water to the consumer. And, because of their incompetence, violation of law, or just plan stupidity or immorality, the refrain commonly heard today is “Let me have that bottled water, please.”
When “Science” Communicated is Not the Truth!
In this text our mantra is that science takes a back seat to almost everything else in our lives because there is a failure to communicate the true benefits of science and its value to all of us. You could say that our mission with this book is a selling job—we are trying to sell science to those who might be scientifically illiterate. However, nothing hurts any selling job (including ours), more than untruths.
Further, nothing reinforces this statement more so than a couple of concrete examples we can all identify with. Consider, for example, whenever you go to the used car lot or a used appliance store. The salesperson expounds upon the merits of the just overhauled used car or the newly renovated, refurbished and retrofitted washing machine—guaranteed to last a long, long time. Most of us are skeptics, so we accept the salesperson’s glowing reports with a bit of caution. Then comes the big test; we actually start the car and hopefully plug-in and test the washing machine. When we start the car we are immediately greeted with a huge, nasty engine backfire and out the rearview mirror we can’t see anything because of the large, dense, black cloud of exhaust. We usually terminate our test drive of the just overhauled car at this point, shake our heads and move off to less smoky pastures, so to speak. Ah, but we still have the newly renovated, refurbished, and renovated washing machine to test, and we do. It turns on okay but immediately we notice that unmistakable sound of a washing machine full of marbles—huge metal ones. So, again, we shake our heads and walk out looking for less metal-strewn pastures.
You know what? It is the same with science. The truth is wonderful, but an untruth undoes it all. Consider two examples we provide below of so-called science (we call it feel-good or voodoo science; you be the judge).
Example 1
An example of untrue media commentary that hurt science and was unnecessarily alarming to the public was the reporting of the use of the herbicide Daminozide (Alar) on apples. Alar is a growth regulator that was used to control the vegetative and reproductive growth of orchard crops such as apples, cherries, nectarines, peaches, prunes, and pears in the late 1980s. It was also used on ornamental plants to control the size and shape of the stems.
Early in 1989, the media reported that Alar was a human carcinogen, was present at detectable levels in apples sold in supermarkets, and would lead to an unacceptable risk if people ate apples containing Alar. Actually, a breakdown product of Alar that forms in water has been shown to cause cancer in lab animals.
In 1986, a fact sheet was produced indicating that there were no restrictions on the use of Alar for registered food crops such as those listed above. However, based partly on public concerns from media reports, the USEPA officially banned Alar from use on any food crops in 1992.
Although the decision to ban Alar from use on food crops was probably the correct decision, the manner in which it was reached was based on public perception from media reports.
The issues not accurately reported by the media included: (1) Alar itself was not a carcinogen, and it was not reported whether the carcinogenic breakdown product was present on the applies sold in supermarkets, and (2) some levels of Alar on apples would lead to exposures so low that the risks would be below any levels of concern. This is why USEPA approved Alar use on apples in the first place.
By not fully reporting these issues, thousands of people became very concerned about getting cancer from eating apples. The risk of developing cancer from eating apples contaminated with the carcinogenic breakdown product of Alar was very low compared to other cancer risks. In addition, the media reporting led to concern that people would experience toxic effects in the short term (e.g., acute effects), even though this concern was unfounded.
For example, using the ranking scale previously listed, Alar would be considered “practically nontoxic,” much like table salt. The amount necessary for Alar to be dangerous may well be extremely high. The lab tests that prompted the scare required an amount of Alar equal to over 5,000 gallons (20,000 L) of apple juice per day. Consumers Union ran its own studies and estimated the human lifetime cancer risk to be 5 per million, as compared to the previously-reported figure of 50 cases per million (Source Watch 2009).
This example illustrates the importance of reporting the actual facts and providing media reports in such a way so that the actual problems can be understood.
Example 2
The second example concerns the fuel oxygenate MTBE (methyl-t-butyl ether). The use of fuel oxygenates was mandated by Congress in the early 1990s to reduce air emissions of gasoline-related toxic chemicals (e.g., benzene, a known human carcinogen). One of these fuel oxygenates, developed for use in gasoline by an oil company, is MTBE. Prior to its use in gasoline, MTBE was commonly used in chemistry labs as a solvent in chromatography. This chemical has a noxious odor and taste, and can be smelled and tasted at very low levels in water (e.g., 10 parts MTBE per billion parts of water). It dissolves easily in water, and gasoline leaks from underground storage tanks at gas stations have led to the chemical reaching groundwater.
Some of this groundwater, especially in southern California where surface water is scarce, is used as drinking water. Human nature is such that people typically associate bad odors with toxicity. Because of the odor and taste of the groundwater due to MTBE, residents in southern California were supplied with bottled water (and many other folks voluntarily replaced their tap water with bottled water).
MTBE is not a particularly toxic chemical—it would be categorized as “practically nontoxic” under the currently used scale. However, one report from a lab in Italy indicated it could cause kidney tumors in lab rodents. After much additional research in the U.S. failed to confirm the Italian study, it was recently concluded (by state of California toxicologists) that MTBE is not a carcinogen. USEPA considers MTBE to be a possible human carcinogen, but research is ongoing.
The media has typically reported that MTBE is a carcinogen, and many environmental groups have requested the additive be banned from use in gasoline because of its impact on our groundwater and surface water. MTBE has been phased out of use in California and phased out or reduced in 17 states (to date) with the support of environmental groups and politicians. The media has played a large role in generating support for such decisions.
As a result, it is easy to understand how the reporting of MTBE has become skewed. For example, a state of Maine regulator said that “public concerns over MTBE lead to all levels of MTBE posing a great health threat to the public, regardless of its toxicity.” This statement literally means that public concern over a chemical can, by itself, make that chemical a health threat, even in the absence of an actual health risk.
Clearly this cannot be true.
It is unclear if the regulator actually meant what this implies, but statements like these, which violate the most basic principles of the science of toxicology (e.g., implying that a health threat is unrelated to toxicity), add to the public’s confusion over the real issues. Hopefully this book will help you understand these issues, and which comments and reports should be dismissed based on their purely emotional or political biases.
Oh, by the way, we will continue to consume bottled water only, thank you very much!
Limitations of Our Current Knowledge
There are several hundred thousand chemicals either naturally produced or manufactured that have some use for humans. We have adequate human toxicology information for less than 100 of these, and adequate animal toxicology information for less than 1,000. Therefore, we do not have adequate information for almost all chemicals.
As we gain knowledge about chemicals, we will find that some present greater concerns than we first thought (e.g., DDT) while others will not pose the threats we thought they might (e.g., MTBE). Lack of chemical knowledge is typically handled by regulatory agencies in a conservative way. In other words, if we do not know the actual toxicity of a chemical to humans, we assume it is high (e.g., precautions taken regarding dioxin at Times Beach and Love Canal). This leads to regulations that should protect us from toxic effects in most circumstances.
Have You Given Up Food Yet?
Some of you might ask: “What a stupid question? Of course we have not given up food . . . heck, we have to eat food, you know . . . to survive and all.” Yes, we know that and we can ensure you that we also eat food, because, like you, we need food to survive. We bring the subject up because (as you have no doubt noticed) every few weeks or so various media sources report some so-called scientific study that professes stark warnings about dire findings about this food or that beverage or this food and beverage combined—the ingestion of any of which or all of which will have some drastic impact on your health or well-being, cause cancer, send us all to the nut house or la-la land, or even worse. Such reports have not only been proven false but also irresponsible in frightening the public about alleged hazards. Virtually every sector of the food pyramid has been vilified as potential health destroyers or killers including: bread and pasta; fats, oils, and sweets; meats and dairy products, fish and seafood; and fruits and vegetables.
When dealing with the food and beverage naysayer of doom and gloom, it is important for us to know or to remember the old and well-worn toxicological saying: “It is not the poison that kills us, it is the dose. In the right amount, all substances are poisons.” And herein lies the problems with the alarmists’ unfounded claims about the toxicity of certain foodstuffs. Any foodstuff (including drinking water), for whatever reason, can be considered a poison if personal intake exceeds a certain threshold level. The alarmists do not tell you that when they harp about the dangers of this or that foodstuff, they conveniently leave out the fact that to become ill or worse you would have to ingest certain foods or drinks at levels that, in some cases, even a hungry or thirsty elephant could not possibly ingest.
Let’s take a look at several of these outlandish and alarmist contentions about food safety from the recent past. Keep in mind that the gist of these condensed statements is not based on any credible science or scientific study that can be called definitive for the exact point claimed. Pure hype and distortion is taken to the extreme to enhance and/or embellish tidbits of information and blow them up into eye-catching headlines.
Bad Foods/Beverages in Various New Reports
For decades, there have been negative headlines about various food and beverages causing health problems. In the 1970s there were various news reports about everything from nitrates in bacon causing cancer to caffeine increasing the risk of birth defects to Red Dye No. 40 causing lymphoma. In the 1980s, there were calls to ban chicken and that salt in processed food can cause heart attacks. In the 1990s, we saw headlines that milk may cause cancer, that there is too much fat in pizza, and eggs contribute to food poisoning. In the 2000s, headlines screamed that fondue may cause cancer and that there is too much fat in muffins and certain Starbucks drinks.
We could go on and on about this list of alarmist, unsubstantiated and/or warped non-scientific statements, but instead we point out that it is the scare tactics inherent in such statements that not only scare people but also alienate many of them from science and anything scientific. However, you should also keep in mind that it is real science, the scientists’ toolbox, unbiased research, and dedicated professionals that in combination always work to disprove and debunk such outrageous claims. This is another area where science proves its real worth.
NOTES
1. This section is adapted from F. R. Spellman (2006). Environmental Science and Technology, 2nd ed. Rockville, MD: Government Institutes Press.
2. From F. R. Spellman (2017). Contaminated Sediments in Fresh Water Systems. Boca Raton, FL: CRC Press.
References and Recommended Reading
Abrahamson, D. E., Ed., 1988. The Challenge of Global Warming. Washington, DC: Island Press.
Asimov, I., 1989. How Did We Find Out about Photosynthesis? New York: Walker & Company.
Bingham, A. K., Jarroll, E. L, Meyer, E. A., and Radulescu, S., 1979. Introduction to Giardia Excystation and the Effect of Temperature on Cyst Viability Compared by Eoxin-Exclusion and in vitro Excystation in Waterborne Transmission of Giardiasis. Jakubowski, J. and Hoff H. C., Eds., United States Environmental Protection Agency. Washington, DC EPA-600/9-79-001.
Black, R. E., Dykes, A. C., Anderson, K. E., Wells, J. G., Sinclair, S. P., Gary, G. W., Hatch, M. H., and Ginagaros, E. J., 1981. Handwashing to prevent diarrhea in day-care centers, Am. J. Epidmilo., 113, 445–51.
Brodsky, R. E., Spencer, H. C., and Schultz, M. G., 1974. Giardiasis in American travelers to the Soviet Union, J. Infect. Dis. 130, 319–23.
CDC. 1979. Intestinal Parasite Surveillance, Annual Summary 1978. Atlanta, Georgia: Centers for Disease Control.
CDC. 1983. Water-Related Disease Outbreaks Surveillance, Annual Summary 1983. Atlanta, Georgia: Centers for Disease Control.
CDC. 1995. Giardiasis. D. D. Juranek. Atlanta, Georgia: Centers for Disease Control.
CDC. 2008. Understanding the Epidemiologic Triangle through Infectious Disease. Atlanta, GA: Centers for Disease Control.
CDC 2009. Infectious Disease Epidemiology. Centers for Disease Control Atlanta. Accessed September 9, 2009.
CDC. 2009a. Giardia Lamblia Fact Sheet. Atlanta, GA: Centers for Disease Control.
CDC. 2009b. Escherichia coli.
CDC. 2009d. Poisoned Picnic. http//www.bam.gov/teachers/activities/ epi _ 6 _ picnic.pdf.
CDC 2018. Methicillin-resistant Staphylococcus aureus (MRSA) https://www.cdc.gov/mrsa/index.html
Daily Mail Reporter (2009). Flesh-eating superbug killed father in just four hours. http://www.dailymail.co.uk/news/article.
De Zuane, J., 1997. Handbook of Drinking Water Quality. New York: John Wiley & Sons, Inc.
Fayer, R., Speer, C. A., and Dudley, J. P. 1997. The general biology Cryptosporidium in Cryptosporidium and Cryptosporidiosis. Fayer, R., Ed. Boca Raton, FL: CRC Press.
Frost, F., Plan, B., and Liechty, B., 1984. Giardia Prevalence in Commercially Trapped Mammals, J. Environ. Health, 42, 245–49.
Herwaldt, F. L., et al, 1997. An outbreaking 1996 of Cyclosporasis associated with imported raspberries, N. Engl. J. Med., 336, 1548–56.
Huang, P., Weber, J. T. Sosin, D. M., et al 1995. Cyclospora, Ann. Intern. Med., 123, 401–14.
Jarroll, E. L., Jr., Gingham, A. K, and Meyer, E. A. 1979. Giardia cyst destruction; effectiveness of six small-quantity water disinfection methods, Am J. Trop. Med. Hygiene, 29, 8–11.
Juranek, D. D., 1995. Cryptosporidium parvum, Clinical Infect. Dis., 21, S37-61.
Kemmer, F. N., 1979. Water: The Universal Solvent, 2nd ed. Oak Brook, IL: Nalco Chemical Company.
Kordon, C., 1992. The Language of the Cell. New York: McGraw-Hill.
Koren, H. 1991. Handbook of Environmental Health and Safety: Principles and Practices. Chelsea, MI: Lewis Publishers.
LeChevallier, M. W., Norton, W. D., and Less, R. G., 1991. Occurrences of Giardia and Cryptosporidium spp. In surface water supplies, Applied and Environ. Microbiol. 57, 2610–16.
Mayo Foundation. 1996. The “Bug” That Made Milwaukee Famous. Rochester, MN.
Metcalf & Eddy, Inc. 2003. Wastewater Engineering: Treatment, Disposal and Reuse. New York: McGraw-Hill, Inc.
Miller, G. T., 1988. Environmental Science: An Introduction. Belmont, CA: Wadsworth Publishing Company.
Nagy, M. H., 1953. The representations of “ germs” by children, Journal of Genetic Psychology, 83, 227–40.
Odum, E. P., 1975. Ecology: The Link between the Natural and the Social Sciences. New York: Holt, Rinehart and Winston, Inc.
Odum, E. P. 1983. Basic Ecology. Philadelphia, PA: Saunders College Publishing.
Panciera, R. J., Thomassen, R. W., and Garner, R. M., 1971. Cryptosporidial infection in a calf, Vet Pathol. 8, 479.
Pennak, R. W., 1989. Fresh-Water Invertebrates of the United States, 3rd ed. New York: John Wiley & Sons.
Price, P. W., 1984. Insect Ecology. New York: John Wiley & Sons.
Rendtorff, R. C., 1954. The experimental transmission of human intestinal protozoan parasites II Giardia lamblia cysts given in capsules, Am. J. Hygiene, 59, 209–20.
Rose, J. B., Gerb, C. P., and Jakubowski, W., Survey of potable water supplies for Cryptosporidium and Giardia, Environm. Sci. Technol., 25, 1393–99.
Singleton, P. and Sainsbury, D., 1994. Dictionary of Microbiology and Molecular Biology, 2nd ed., New York: John Wiley & Sons.
Slavin, D. 1955. Cryptosporidium melagridis, J Comp. Pathol, 65, 262.
Smith, R. L., Ecology and Field Biology. New York: Harper & Row.
Source Watch, 2009. Alar and Apples. http://sourcewatch.org/index.php?title=Alar_and_apples#The_risks_of_Alar. Accessed September 16, 2009.
Spellman, F. R., 1996. Stream Ecology and Self-Purification: An Introduction for Wastewater and Water Specialists. Boca Raton, FL: CRC Press.
Spellman, F. R., 1997. Microbiology for Water/Wastewater Operators. Boca Raton, FL: CRC Press.
Tchobanoglous, G. and Schroeder, E. D., 1985. Water Quality. Reading, MA: Addison-Wesley Publishing Company.
Tyzzer, E. E., 1912. Cryptosporidium parvum sp.: a Coccidium found in the small intestine of the common mouse, Arch. Protistenkd, 26, 394 m.
Upton, S. J., 1997. Basic Biology of Cryptosporidium. Kansas State University.
Walsh, J. D., and Warren, K. S., 1979. Selective primary health care: an interim strategy for disease control in developing countries, N. Engl. J. Med., 301, 974–76.
Weller, P. F., 1985. Intestinal protozoa: Giardiasis, Scientific American Medicine.
WHO. 1990. Guidelines for Drinking Water Quality, 2nd ed., Vol. 2, Austria.
Wistriech, G. A. and Lechtman, M. D., 1980. Microbiology, 3rd ed. New York: Macmillan Publishing Company.