2

The McConnon Strain

Patrick J. McConnon, the U.S. CDC Regional Southeast Asia Coordinator for Refugees, was sick to his stomach, dreading the decision he had to make. It was a rainy day in spring 1982, and he was sitting in the CDC regional office in Bangkok, Thailand. He had expected a routine phone call, letting him know how many Cambodians—men, women, and children—were scheduled to undergo medical screening as part of the standard process of resettlement in the United States. But this time, the transport arrangements had changed. Due to the large number of refugees—nearly twenty thousand people—the medical processing would not take place nearby, at the local transit center in Phanat Nikhom. Instead, the refugees would be bused from the Kamput refugee camp directly to the Bangkok airport and then flown out of the country to a much larger processing center in Bataan, in the Philippines.

McConnon was afraid that this change in logistics might have huge unintended consequences that would be difficult or impossible to control. Just the other day, he had learned that some Kamput refugees might harbor an unusual infectious disease: a drug-resistant, life-threatening form of malaria. Knowing how easily disease can spread, he did not want the refugees to leave the country without being screened. But what should he do? If he stopped the flight to Bataan, he would prolong the misery of thousands of desperate families eager to resettle and start a new life—and there would also be major political repercussions, not to mention personal repercussions for the bearer of bad news. But if he let the refugees leave, he could be aiding and abetting the spread of a dangerous disease that could bring illness and death to thousands of people throughout the world.

McConnon pushed himself out of his chair and looked out the window at the empty daytime streets of Patpong, the gaudy red-light district of Bangkok,1 now dark and dreary from constant rain. He thought about the homeless Cambodians in Kamput, uprooted by the Khmer Rouge, forbidden by Thai authorities to live outside the camp, and afraid to return to Vietnamese-occupied Cambodia. Then he thought about the people he worked with in other Southeast Asia countries—Filipinos, Vietnamese, Laotians, Indonesians, Malaysians—and how quickly diseases can spread from one country to another. He vowed not to let it happen on his watch.

Refugee Camps and Medical Screening

People stranded in refugee camps, displaced, impoverished, and malnourished, are at special risk for infectious diseases such as malaria, measles, and cholera that flourish in crowded and unsanitary living conditions. When infected refugees are moved to new holding sites, repatriated, or resettled in new countries, they can bring these diseases with them. As a result, public health officials like McConnon have overlapping and sometimes conflicting aims: to safeguard the health and welfare not only of the refugees themselves, but also of the people in countries that host refugees camps or accept refugees as permanent residents

The spread of smallpox after the 1971 Pakistani civil war illustrates what can happen when a pathogen incubated in a refugee camp infects the wider population. Smallpox was carried to the newly established nation of Bangladesh by refugees returning home from India. According to public health lore, the presence of smallpox in the camps was detected by an epidemiologist in Atlanta, sitting in his living room watching TV, who noticed a man with a suspicious rash in a newsreel about a camp near Calcutta. The man’s face was covered with the large pus-filled lesions characteristic of advanced smallpox. The epidemiologist called the director of the CDC, who called the director of the World Health Organization (WHO) Smallpox Vaccination Program, who called the Indian Ministry of Health. But it was already too late. Thousands of Bengalis had already left the camp, leading to widespread outbreaks in Bangladesh and making it the last Asian country to finally eliminate smallpox.

Medical screening procedures to prevent refugees from carrying disease into the United States were written into the Refugee Act of 1980, which was drafted in response to the refugee crisis that followed the end of the Vietnam War and the rise and fall of the Khmer Rouge in Cambodia. The Refugee Act requires applicants for resettlement in the United States to pass a rigorous medical examination that includes testing for “inadmissible” or “quarantinable” diseases, such as smallpox, cholera, plague, diphtheria, infectious tuberculosis, yellow fever, and viral hemorrhagic fevers like Ebola and Marburg. Severe acute respiratory syndrome (SARS) was added in 2003, and influenza caused by viruses with the potential to cause a pandemic was added in 2005.

For the Cambodian refugees who applied for U.S. visas in 1982, medical screening was the last step in a long process that began with a preliminary interview by a worker from the Joint Voluntary Agency (JVA), a nongovernment organization under contract to the U.S. Department of State. Typical JVA workers were a mix of idealistic young Americans, hoping to help the refugees, and less altruistic individuals that the old-timers called “world travelers” or “WTs”—adventurers and drifters hoping to earn money to fund their peregrinations. The job of the JVA interviewer was to ensure that all prospective U.S. immigrants fulfilled the minimum requirements of the U.S. Immigration and Naturalization Service (INS). They gathered as much information on each applicant as they could to gain insights into their local customs and attitudes. They asked each applicant whether he or she had relatives or sponsors in the United States or had ever been employed by the U.S. government. They also tried to determine whether the applicant had been a member of the Khmer Rouge. Members of Cambodian resistance groups, including those faithful to Pol Pot, to Prince Norodom Sihanouk, or to former Prime Minister Son Sann, continued to congregate on the Cambodian side of the border and sometimes used the border camps as bases for their operations.

Individuals recommended for INS consideration by JVA workers were interviewed a second time by INS personnel and then—if they passed—were sent to Phanat Nikhom, about sixty-five miles southeast of Bangkok, for medical screening. Many of the refugees were in poor health, requiring treatment for malaria, tuberculosis, anemia, hepatitis, upper respiratory tract infections, or intestinal parasites. Individuals with malaria were treated with a dual regimen of quinine and tetracycline, rather than the standard local treatments of chloroquine (CQ) or sulfadoxine-pyrimethamine (SP), because many local malaria strains were either CQ-resistant or SP-resistant. Individuals with tuberculosis were not allowed to leave for the United States until their illness was controlled with a multidrug treatment regimen administered for at least six months.

Malaria—a scourge known since ancient times—is even today one of the primary causes of illness and death in refugee camps. However, it is not included on the U.S. list of inadmissible diseases or on the WHO list of reportable diseases because it is not transmissible from person to person and is not rare or unusual. It is endemic in the equatorial regions of Asia, Africa, and South America, where it currently affects 350 to 500 million people. Malaria was eliminated in most urban areas in Cambodia and Thailand after World War II due to the WHO Global Malaria Eradication Campaign (1955–1969), whose main weapon was the insecticide DDT because there was (and is) no vaccine against malaria. By the time of the Khmer Rouge, however, malaria had resurged in rural areas. In 1979, it was the most common cause of death among the Cambodian refugees who fled through western Cambodia to reach the border with Thailand.

The Investigators

McConnon, born and raised in Minnesota, was an expert in public health operations and logistics who had worked as a public health advisor in Ohio, Virginia, and Minnesota, and at CDC headquarters in Atlanta, as well as with the WHO Smallpox Eradication Program in Bangladesh and Somalia. He had arrived in Bangkok nine months earlier, in August, 1981, with his wife, Kate, young daughter, and teenage son. His role included quality control and oversight of refugee medical screening, as well as evaluation of any acute public health issues that affected people displaced in the aftermath of the Vietnam War. These included refugees from Cambodia, Vietnam, and Laos (including Hmong) who fled overland to Thailand, and the Vietnamese “boat people” who fled by sea to any country that would admit them, ending up in refugee camps in Thailand, the Philippines, Singapore, Hong Kong, Malaysia, or Indonesia.

McConnon visited the refugee camps in these countries every two months, staying in the tin-roofed huts or guest houses that served as staff quarters in each camp. He conferred with the relief workers who staffed the camps’ medical clinics and facilitated movement of refugees to processing centers for medical screening and classes in language and cultural orientation. In 1982, the United Nations High Commissioner for Refugees (UNHCR) supported three major international processing centers, in Phanat Nikhom, Thailand; Galang, Indonesia; and Bataan in the Philippines. Refugees seeking resettlement in Western countries were also processed and screened at transit camps in Singapore, Hong Kong, Macao, and Malaysia.

While in Bangkok, McConnon lived with his family in a traditional wooden Thai house within a large compound that also included a three-story apartment building with a Japanese family on each floor, as well as a central building—the “main house”—that provided lodging for the compound’s staff, including housekeepers, cooks, and gardeners. The McConnons’ house was all red inside, with mahogany floors and ceilings, more cozy than elegant, but old and impressive, with air conditioning in the upstairs bedrooms and ceiling fans in the living and dining rooms. Air conditioning was an important amenity because temperatures in Bangkok rarely dropped below 70 °F (21 °C), even during the “cool season” (December through February). During the rainy season (May through November), the whole compound would be flooded for days. After breakfast, McConnon and his wife and children would take off their shoes and socks, roll their pants or skirts up to the knees, and wade through the water to the road outside the compound to catch a taxi or board the school bus.

McConnon’s children attended an international school in Bangkok, and his wife Kate worked at the Orderly Departure Program (ODP). ODP was established in 1979 as a safe and legal path to emigration for Vietnamese nationals with family in the United States, including children born to Vietnamese mothers and American G.I. fathers. While all of the McConnons learned to speak Thai well enough to say hello to neighbors and order food in restaurants, McConnon’s ten-year-old daughter became quite fluent. On school holidays, the McConnons’ cook and housekeeper took her with them to the countryside to attend Buddhist religious festivals, which were colorful and exciting and unlike anything she had experienced at home.

Among the McConnon’s closest friends in Bankgok were two relief-agency colleagues, Roland Sutter, a Swiss physician, and his Vietnamese wife, Xuan, a former refugee who fled Saigon by boat with her family in 1975. Rescued by the U.S. Seventh Fleet, she had lived in a camp in Guam, resettled in Canada, and returned to Southeast Asia as a Canadian relief worker at the Galang refugee camp in Indonesia. Her current job was as an interviewer and translator at ODP, where she worked with Kate McConnon. Her husband, whom she had met in Indonesia, was the regional medical officer of the Intergovernmental Committee on Migration, an organization founded in Switzerland in 1951 to facilitate emigration of Europeans displaced during World War II. In 1982, the Intergovernmental Committee on Migration was on contract to the U.S. Department of State to oversee the doctors and nurses hired to screen U.S.-bound refugees from Southeast Asia. A fit, sophisticated man in his thirties, Sutter was responsible for organizing and overseeing medical screening for all refugees in Southeast Asia. His duties included verifying that the medical screening of refugees accepted for resettlement in a given country fulfilled the legal screening requirements of that country. In Phanat Nikhom, he supervised the medical personnel on contract to the U.S. Department of State and worked in partnership with McConnon to ensure fulfillment of U.S. government regulations.

McConnon’s other duties required a certain degree of flexibility and resourcefulness, especially when he was called on to do odd jobs related to health but outside his usual job description. Once, when he was still new at the job, his secretary informed him that he had a “dog head problem.” In the waiting room was a man from Phanat Nikhom clutching an oversized red plastic ice bucket from which protruded the elongated snout of a very large dog. Fascinated and repulsed (and lacking any expertise in rabies diagnostics), McConnon carried the bucket by taxi to a rabies specialist at Chulalongkorn University who confirmed that the head had belonged to a rabid dog and that any persons bitten by that dog required treatment. Another time, McConnon helped a senior Thai dignitary suffering from respiratory distress by shipping a vial of his blood to CDC laboratories in Atlanta, which detected Histoplasma capsulatum, a fungus spread by bird or bat droppings that can cause a fatal lung disease if left untreated.

McConnon’s job also required a willingness to take a stand. Although the Bangkok posting was his first assignment in refugee health, McConnon had seen in Bangladesh first-hand evidence of international disease spread by infected refugees. Tall and bearded, McConnon is a soft-spoken, straightforward person who is not afraid to express his mind. Having taken on many challenging assignments for the CDC, he was well aware of the political pressures and personal agendas that can interfere with public health decision-making, and he tried always to focus on the public good. Since arriving in Bangkok, he had twice ordered the cancellation of flights carrying Vietnamese refugees to the United States. The first occurred in Hong Kong, where a chickenpox outbreak was raging among young children in the refugee camp. The second was in Singapore, when procedures for preboarding screening for fever and rash were poorly implemented by inexperienced airport personnel. McConnon had agonized over these difficult but necessary decisions.

After the airport incidents in Hong Kong and Singapore, McConnon and Sutter worked together to establish routine procedures for preboarding screening of refugees for fever, cough, and rash. Another joint project involved working with refugee camps and transit centers in Southeast Asia to institute directly observed therapy for tuberculosis, the same strategy of daily, documented treatment used in the United States to contain the reemergence of tuberculosis in New York City.

To keep abreast of any new health issues that might arise in the refugee camps, McConnon and Sutter attended monthly UNHCR coordination meetings attended by representatives of more than 50 humanitarian relief agencies that worked in the refugee camps along the Thailand–Cambodia border. The meetings were run by Arcot G. Rangaraj, the UNHCR health officer in Thailand, a former Indian Medical Service surgeon with an impressive military record and a ramrod-straight bearing. In 1945, as the Regimental Medical Officer of the 152nd Indian Parachute Battalion, he had parachuted into Burma (now Myanmar) at Elephant Point as part of an attack on Japanese-occupied Rangoon called Operation Dracula. During the Korean War, he commanded the Indian Army’s 60th Parachute Field Ambulance Platoon, a mobile army surgical hospital that evacuated wounded British troops and was known for its courage under fire. Skilled at both medicine and war, Rangaraj joined the WHO in 1969 as Senior Advisor on Smallpox Eradication, first in Afghanistan and later in Bangladesh and the Arabian Peninsula. McConnon and Rangaraj developed a special bond when they realized they had both worked in Bangladesh in 1975, the final year of the smallpox eradication effort in Asia.

Rangaraj’s UNHCR meetings served as a relief-agency grapevine for refugee health issues. There health workers learned about vaccine-preventable neonatal tetanus among the Hmong—who refused to allow their sons to be vaccinated because they believed it caused a baby’s testicles to recede—as well as malnutrition, outbreaks of enteric disease, and bites by rabid animals. (As McConnon found out after his “dog head” experience, canine rabies was fairly common in Thailand, and not only in the refugee camps, because the local custom was to feed wild dogs rather than kill them or house them in dog pounds).

It was at a UNHCR meeting that McConnon and Sutter first heard about cases of malaria in Kamput that exhibited a type of multidrug resistance unknown outside of Cambodia and Thailand (and extremely rare in Thailand). According to healthcare workers at the Kamput clinic, the patients did not recover after treatment with either CQ (the cheapest and most widely used antimalarial drug) or with SP. McConnon made a mental note to keep track of malaria patients in Kamput in case additional cases of multidrug resistance turned up during the following months.

The Public Health Problem

The refugee situation in Southeast Asia involved hundreds of thousands of people uprooted by a succession of wars and invasions. McConnon arrived in Bangkok at the end of the second large wave of refugees who fled into Thailand. The first wave (1975–1977) occurred after the fall of Saigon and the withdrawal of U.S. troops from Vietnam. The second and largest wave (1978–1982) occurred after the defeat of the Khmer Rouge by the Vietnamese at a time of widespread famine. A third wave occurred in the mid-1980s after Vietnam expelled its ethnic Chinese population in reaction to an invasion by China that led to continued regional conflict.

The second wave included about two hundred thousand Cambodians who reached Thailand after surviving malnutrition, exposure to malaria, and gunfire from soldiers, bandits, and border guards. They included members of Pol Pot’s army, as well as starving civilian families fleeing the occupying Vietnamese forces or the Khmer Rouge, or both. UNHCR supported construction of makeshift border camps, and the World Food Program provided food and humanitarian aid, assisted by the United Nations Children’s Fund (UNICEF), the International Committee of the Red Cross, and many other relief agencies.

By 1982, the Thai border camps had evolved into small villages with bamboo-and-thatch–roofed huts, vegetable gardens, food markets, and medical and relief services. Certain camps, including Kamput, were designated as holding centers for refugees awaiting repatriation in Cambodia or resettlement in a new country. The largest camp, Khao I Dang, housed about 130,000 refugees, making it the largest Cambodian city in the world at the time, because Phnom Penh had been “evacuated” by the Khmer Rouge.

About twenty thousand second-wave Cambodians who claimed refugee status were admitted to the United States from 1979 to 1981; most had family ties or economic sponsors in the United States. In mid-1981, however, the INS ruled that the Refugee Act of 1980 required case-by-case proof that a refugee was at risk for persecution if repatriated in Cambodia. This requirement was difficult to fulfill, and many previously eligible visa applicants were rejected by INS and left in stateless limbo in the border camps. By this time, however, the refugee crisis in Southeast Asia had become a political issue in the United States because of widespread news reports about the Vietnamese boat people and the “killing fields” of Cambodia. (Closer to home, the 1980 Mariel boat lifts—which included individuals released from Cuban prisons—also heightened public awareness of refugee issues.) Several U.S. aid groups and individuals, including State Department officials, senators, and congressmen, spoke out on behalf of the Cambodian refugees and acknowledged U.S. responsibility in creating the refugee crisis. They drew attention to failed attempts at forced repatriation of Cambodians by the Thai government that resulted in the death of refugee families caught between the occupying Vietnamese army and Cambodian resistance forces.

In early 1982, the INS agreed to relax the standards of proof and admit about twenty thousand additional refugees, all at one time, as a step toward emptying the border camps. This decision was a welcome development for everyone. It meant that thousands of uprooted families might soon find homes in the United States and that the border camps might soon be closed.

However, there was one problem, obvious to a public health person like McConnon, if to no one else. To speed the processing of so many people, the State Department decided to move thousands of refugees from Khao I Dong to Kamput for prescreening and then (if JVA approved them) directly to the refugee center in Bataan, bypassing the usual six to eight week stay in Phanat Nikhom. Medical screening would not take place until after the refugees arrived in the Philippines.

From a public health point of view, moving unscreened refugees out of a country is never a good idea, and McConnon thought it was especially unwise in this instance because of the multidrug-resistant malaria reported in Kamput. If refugees from Khao I Dong acquired drug-resistant malaria during their stay in Kamput—which was entirely possible—they could spread disease to the Philippines and beyond. Although refugees with obvious malaria symptoms, like fever and chills, would be prevented from flying by the preboarding screening procedures instituted by McConnon and Sutter, people who were infected but not yet experiencing symptoms could go undetected. (The incubation period—the time between infection and the appearance of symptoms—for malaria is usually ten days to four weeks.)

To make matters worse, the malaria cases reported at the Kamput clinic were caused by Plasmodium falciparum malaria, the more dangerous of the two types of human malaria endemic in Southeast Asia (the other is Plasmodium vivax).2 Malaria is caused by parasites that are carried by mosquitoes and cause severe fever and chills during the “blood-stage” portion of the parasite life cycle (see insert). P. falciparum is especially dangerous to children under five years old, who are too young to have developed immunity through repeated exposures, and to pregnant women, who are at high risk for anemia. Coma and death can result from cerebral malaria, a complication that occurs when P. falciparum–infected blood cells attach to the walls of blood vessels in the brain.

To make matters even worse, the Bataan Peninsula was a particularly malarious area. Forty years earlier, malaria had been a significant factor in the Allied defeat at the Battle of Bataan. Thousands of Filipino and U.S. troops died from malaria before and during the battle, as well as during the forced “Death March” to a prison camp in Capas, Philippines, that followed the surrender to the Japanese. A U.S. veteran recalled Bataan as “one of the most heavily malaria-infested areas in the world,”3 with mosquitoes everywhere and a scarcity of the antimalarial drug quinine for infected soldiers on both sides of the war. During the 1980s, despite the partial success of the WHO Global Malaria Eradiation Campaign, malaria was still an important health problem in several Filipino provinces, including Bataan. The introduction of a multidrug-resistant strain into Bataan would be disastrous.

Although McConnon did not know it, the Thailand–Cambodia border region was a longtime incubator of drug resistance in P. falciparum parasites. In fact, Kamput is located within twenty-five miles of Pailin, a Cambodian mining town identified by the medical historian Randall Packard as a world epicenter for the development of antimalarial drug resistance.4 Packard argues that resistance to CQ—the drug that replaced quinine as the antimalarial drug of choice after World War II—arose in Pailin during the 1950s and 1960s from a confluence of factors that included mining practices, migration patterns, and misguided public health efforts.5

In 1982, Pailin was known as a Khmer Rouge stronghold, a place where Khmer Rouge leaders retreated after the Vietnamese Army overthrew Pol Pot, funding resistance operations by smuggling gems and timber. But in the aftermath of World War II, Pailin’s mines had attracted a constant flow of transients—mostly impoverished farmers—from other parts of Cambodia and from Thailand, Vietnam, and Myanmar, who dug up rubies and sapphires and sold them for a few dollars apiece to local merchants. The migrants slept out in the open or in rudimentary shelters with no bednets to protect them from Anopheles dirus, a local night-biting mosquito that bred in used-up mining shafts full of stagnant water. Although people who survive to adulthood in malarious areas usually have partial immunity to malaria, many of the migrants came from less malarious areas, had little or no immunity, and tended to become very sick, with high concentrations of parasites in their blood that were transmitted by mosquito bite to other people.

Since A. dirus is an outdoor feeder unaffected by indoor spraying with DDT, efforts to control malaria among the miners focused on administration of CQ as a preventive measure. But the procedure apparently backfired. Although the means of distribution varied from year to year—given in pill form in varying doses or ingested in food seasoned with medicated salt—the dosages were never high enough to kill any but the most CQ-sensitive parasites, providing a selective advantage to parasites that were CQ-resistant. Moreover, migrants suffering from malaria who used their mining profits to purchase additional CQ usually could afford only enough for a subcurative dose, further boosting the survival rates of CQ-resistant parasites. Successive malaria epidemics among new groups of nonimmune migrants who ingested high but noncurative doses of CQ apparently amplified CQ resistance from year to year until, by the early 1970s, most P. falciparum parasites in the border region were moderately or extremely resistant to CQ. SP, a new drug combination, came into use in Thailand in the mid-1970s as a second-line drug for use when CQ failed.

In 1982, malaria resistance to both CQ and SP (dual resistance) was rare and had never been reported outside of Thailand and Cambodia—and McConnon wanted to keep it that way. He thought about his decisions to cancel the flights in Hong Kong and Singapore, both of which had been very difficult. He was now faced with the prospect of exercising his flight-cancellation authority a third time, in a situation that involved many more people and a much more highly charged political situation.

Map of Thailand and Cambodia indicating the locations of the Kamput and Khao I Dang refugee camps, the transit center at Phanat Nikhom, and the mining town of Pailin. Source: CSTE: Edward Chow, Lauren Rosenberg, and Jennifer Lemmings.

McConnon confided in Sutter, who agreed that multidrug-resistant malaria must not spread on their watch. McConnon recalled his experiences in Bangladesh battling smallpox spread by repatriated refugees. He and Sutter joked bitterly about the world-renowned, drug-resistant “McConnon strain” that might spread worldwide if they failed to act.

With Sutter’s encouragement, McConnon contacted Mac Allan Thompson, the State Department official in charge of the U.S. Indochina Refugee Program. Thompson, a graduate of the Colorado School of Mining and Engineering, was a Vietnam veteran who had returned to Southeast Asia as a government official. He was energetic, athletic, and fearless and had only recently returned to work after breaking his back while teaching sky-diving—his weekend hobby—to Thai military officers. He was also thoughtful and independent-minded, with the air of someone who was always one step ahead. He had contacts and sources of information everywhere, including such remote places as the Golden Triangle, an opium-producing area in the mountains of Myanmar, Laos, and Thailand.6

McConnon was somewhat nervous. Thompson could be outspoken and play rough if someone contradicted him or interfered with his plans and operations. He also knew that Thompson was under intense pressure to move the refugees to Bataan. With great trepidation—and the specter of the “McConnon strain” filling his mind—McConnon took Thompson aside and said he had something surprising and serious to tell him. Then he explained why they could not send unscreened refugees to the Philippines.

Thompson’s first reaction was to dismiss McConnon’s concerns out of hand. He reminded McConnon that resettlement of the refugees was important from both humanitarian and political standpoints and that additional supplies had already been shipped to Bataan. When McConnon insisted he would not allow the refugees to board the airplane, Thompson reminded him that he had clear authority only to prevent travel into the United States, not necessarily between Thailand and the Philippines.

When McConnon still did not back down, Thompson asked whether McConnon was absolutely certain of the accuracy of the reports of malaria from the Kamput clinic. After all, the clinic lacked sophisticated diagnostic tests, and malaria can be mistaken for other febrile diseases. McConnon admitted he was not certain. Nevertheless, he knew from experience that when it comes to public health, being over-cautious is a good thing. “Well then,” said Thompson, “we have four weeks before the move to Bataan. If you can provide some evidence that the danger is real, I’ll see what I can do.”

The Investigation

McConnon and Sutter lost no time in mounting an investigation to confirm the reports of multidrug-resistant malaria and determine how the disease was spread. Although neither McConnon or Sutter had formal training in epidemiology, they were familiar with basic epidemiologic tools, such as case-control studies and retrospective studies, that could help them figure out why some people were getting ill and others were not. If they could identify behaviors or activities that put refugees at risk for acquiring malaria (called “risk factors”), they would know which individuals were most likely to be infected with the drug-resistant disease. In that instance, they could stop those individuals from going to Bataan, and McConnon might not have to cancel the flights.

They began by brainstorming about occupations or activities that might bring the refugees into contact with mosquitoes. Although they did not know which Anopheles species lived in eastern Thailand, they assumed that mosquitoes are likely to be highly concentrated in forests or near swamps or other bodies of standing water where they breed. They also knew that some types of mosquitoes are most active at night or evening, whereas others tend to feed in the early morning or late afternoon.

The Kamput refugee camp was tiny—perhaps ten acres—and entirely surrounded by barbed wire. It included a living area filled with family huts, a forested area, and some swamplands. Some refugee families kept chickens in their yards and had planted small vegetable gardens near their huts or near the forest. It was possible that farmers whose gardens bordered forests were most at risk for malaria. Or perhaps other tasks—such as fetching water from wells or ponds in the early morning or taking garbage to be buried in a makeshift dump inside the forest—increased proximity to mosquitoes.

To test these hypotheses, McConnon and Sutter designed a case-control study. This type of study compares a group of patients (the case-patients) with a group of people who are not sick (the controls) to determine which risk factors are associated with illness and which are not. They planned to compare malaria patients seen at the Kamput clinic with healthy camp residents matched by age and sex. To confirm the case-patients had malaria and not some other febrile disease, they needed to perform standard diagnostic tests for malaria called “thick smears” and “thin smears,” which they did not know how to do. They called on Dr. Peter Echevarria, a malaria expert at the U.S. Armed Forced Research Institute for Medical Science in Bangkok, and convinced him to lend them a hand. Dr. Echevarria not only taught them how to make blood smears but also organized the laboratory part of the case-control study.

Viewed under a microscope, a “thick smear”—a finger-prick’s drop of blood spread out on a glass slide—reveals the percentage of red blood cells that are infected with malaria parasites (the parasite density or “parasitemia”). Parasitemia high enough to be detected on a thick smear is generally seen during the blood stage of the illness, when the patient is experiencing fever and chills. A “thin smear”—a drop of blood spread over a larger area—provides a clear view of individual parasites, enabling the investigator to determine which type of parasite is present (for example, P. vivax or P. falciparum).

With assistance from Dr. Echevarria and colleagues in the Kamput clinic, McConnon and Sutter obtained blood samples from Kamput residents who had malaria symptoms (fever and chills), as well as from a control group of healthy refugees. McConnon took care of the logistics, and Sutter prepared the blood smears. They determined that nearly all of the case-patients did in fact have malaria—and that each malaria case was caused by P. falciparum parasites. To their disappointment, however, they did not see any clear differences in activities between the people with malaria and the people without it, probably because the number of newly identified malaria cases was too small to generate any statistical correlations.

McConnon and Sutter decided to use a second epidemiologic tool, a retrospective study of malaria cases observed in Kamput over the previous six months, using the medical records of the Kamput clinic. They began by agreeing on a case definition for malaria: high fever accompanied by headache, muscle pain, chills, sweats, nausea, or diarrhea. With help from Dr. Eschevarria, they searched through the logs of the Kamput clinic, line by line, to find people in whom malaria had been diagnosed or whose symptoms matched the case definition, from December 1981 through May 1982. For each case of malaria, they recorded the patient’s age, sex, marital status, and occupation. They also recorded the drug treatment each patient received and whether the treatment failed.

McConnon and Sutter plotted the location of each malaria case identified in either the case-control study or the retrospective study on a map of Kamput, hoping to see a pattern. But the data did not support any of their hypotheses. There was no correlation between risk for malaria and activities such as farming, house-building, chicken-raising, water-collection, and working near the forest, swamp, or garbage dump. In fact, the distribution of malaria cases seemed entirely random, except for one thing: nearly all cases involved males thirteen to fifty-five years old. The few malaria cases among women or children were found in the clinic records as part of the retrospective study and had not been confirmed with blood smears, so they might not have been malaria cases at all.

What did this mean? McConnon and Sutter were stumped.

The Missing Puzzle Piece

Seven days before the refugees were about to embark for Bataan, McConnon and Sutter found a solution to their dilemma in an abrupt and unexpected way. They were sitting at the bar at the local JVA guest house on the main road adjacent to the Kamput camp, debating what to do next. They had no new evidence to convince Thompson to hold the refugees in Thailand. The flights to Bataan were imminent, and the emergence of a “McConnon strain” no longer seemed an impossible joke. How could they stop this disaster?

Sutter had informed his superiors about the problem, and McConnon had alerted the CDC. But McConnon’s supervisors believed that an on-the-ground issue was best evaluated on-site, rather than half a world away in Atlanta. So McConnon continued to agonize over what he should do. Should he make more phone calls to CDC scientists or public health experts to see if they could think of any alternatives? Should he try again to persuade Thompson? Should he threaten to resign his post in protest? These questions had kept McConnon up at night, and now he and Sutter were reviewing their data one last time. They must be missing something big—something difficult to see because of inadequate data, too few active cases, hypotheses they hadn’t thought of, or questions they hadn’t asked. There had to be something.

McConnon and Sutter ordered beer from the guest house kitchen. As they continued the postmortem of their inconclusive data, they were joined by colleagues from JVA who had spent the day in Kamput interviewing refugees. One was a Texan named Richard who played on McConnon’s softball team in a recreational league run by the U.S. Embassy. Richard belonged to the idealistic category of JVA workers, who wanted to improve the lives of the refugees. “McConnon,” he said, “You don’t look so good. Let me buy you another drink.”

“I feel like crap,” said McConnon, and proceeded to tell him about the malaria investigation and how none of their theories held up. To his surprise, the men from JVA started smirking, and Richard was positively gleeful: “Why didn’t you tell me about this before, you idiot! I could have told you the answer a long time ago! We have a saying at JVA that anyone in the camps with malaria is a gun-runner for the Khmer Rouge!”

McConnon’s jaw dropped. Sutter gave a quick “oh yes!” smile. This was the missing puzzle piece—a convincing explanation of their data and a solution to their problem. The refugees living in Khao I Dang—the only camp directly overseen by the Thai Government and UNHCR—were unlikely to be members of Cambodian resistance groups. But Kamput itself, like each of the small border camps, had been infiltrated by resistance groups from its inception. So it was not difficult to believe that a small number of smugglers—men and adolescent boys—were crossing the border at night on their way to Khmer Rouge bases like Pailin, exposing themselves to night-biting mosquitoes and carrying disease as well as guns, sapphires, or timber between Thailand and Cambodia.

McConnon phoned Thompson to withdraw his objection to the State Department’s travel plans for the U.S.-bound Cambodian refugees. He felt confident the JVA interviewers and INS officials would not recommend males with a history of recent malaria (whether drug-resistant or drug-susceptible)—or any other males suspected of being Khmer Rouge—for inclusion in the group of refugees sent to Bataan. Moreover, the Kamput Clinic continued to report sporadic malaria cases among males only, indicating that malaria transmission was not occurring within the camp, where it would have affected men, women, and children.

Much relieved, McConnon and Sutter realized that in their haste to meet Thompson’s deadline they had neglected a key part of a public health investigation: talking to local people who understand the day-to-day realities of the affected population. Without that basic knowledge, interpretation of epidemiologic data can be difficult or impossible. While an intense focus on data and methodology is essential to any investigation—and ingrained by scientific training and habit—veteran epidemiologists tend to acquire what anthropologists call “participant observation” skills: the ability to gain qualitative understanding of local activities and attitudes through their own experience. Until they gain those skills, inexperienced epidemiologists can miss crucial information that (as in Poe’s The Purloined Letter) is hiding in plain sight.

Aftermath

About three-fifths of the twenty thousand Cambodians interviewed at Kamput were recommended by JVA, approved by INS, and flown to Bataan for medical screening, language classes, and orientation. A total of 20,234 Cambodian refugees from the border camps were resettled in the United States during 1982. Many were reunited with “first wave” family members who had created Cambodian–American enclaves in towns such as Long Beach, California, and Lowell, Massachusetts. Others were resettled in groups in large cities such as Atlanta, Boston, Chicago, Cincinnati, Columbus, Dallas, Houston, New York City, and Phoenix.

In December 1982, the U.S. government discontinued financial support to the refugee camps, and Kamput was closed soon thereafter. Khao I Dang remained open for another decade, not closing until 1992. Most Cambodians who remained in the camps were considered economic migrants rather than refugees, and relatively few were eligible for resettlement in the United States or other Western countries. In 1993, the last Cambodian refugees were repatriated, and the rest of the border camps were closed. Of about 370,000 displaced Cambodians, about 220,000 had been admitted to Western countries, including 147,000 to the United States.

Twenty-five years after the closure of Kamput, we can say with confidence that U.S.-bound Cambodian refugees did not spread multidrug-resistant malaria to the Philippines. That this was a real danger and not an overreaction by McConnon and Sutter is borne out by DNA studies that identify Southeast Asia (especially the Thailand–Cambodia border region) as the origin of malaria strains with SP- or CQ-resistant mutations that subsequently spread to Oceania, Africa, and South America, especially during the 1980s and 1990s.7 Today, multidrug resistance to CQ and SP is found throughout the Mekong region, as well as in East Africa.

In contrast, multidrug-resistant malaria has made little headway in the Philippines, where malaria has been eliminated in most of the country. Malaria is no longer found in Filipino cities and highlands and is a major cause of death in only five of eighty-one provinces (Palawan, Isabela, Tawi-tawi, Sulu, and Butuan City). Malaria still occurs in the province of Bataan but at a very low level. Until recently, CQ remained the antimalarial drug of choice throughout the Philippines, with SP reserved for treatment of CQ-resistant illness. In 2003, however, in response to increased reports of resistance to either drug alone, the Filipino Department of Health began recommending combined use of CQ and SP as first-line therapy, with artemether-lumefantrine as the second-line drug.

It seems inevitable that this change in Filipino medical practice eventually will lead to the emergence of strains of malaria with resistance to both CQ and SP. However, the consequences to the Philippines—and perhaps to other countries, if the resistant strains spread—will not be as grave as they would have been in 1982, when fewer drug choices were available to treat malaria.