Serengeti Plains
The tsetse fly uses its long proboscis to pierce through multiple layers of clothing to feed on human blood. It also is the carrier of a deadly parasite: African trypanosomiasis, or sleeping sickness. Under a microscope, these tiny creatures resemble eels. Once inside a mammal, the parasites rapidly reproduce. While human infections number only a few thousand each year, the tsetse devastates Africa’s livestock, causing losses of $4 billion annually.
In Moses’s time, the fourth plague of Egypt was likely tsetse flies: “If you do not let my people go, I will send swarms of flies upon you and your officials, on your people and into your houses.” The fifth plague was a disease that wiped out the Egyptians’ livestock. Could this have been African sleeping sickness?
While sleeping sickness kills cattle, African animals possess a natural resistance to it. Whenever agriculture tried to establish itself where tsetse flies lived, European livestock (and sometimes the people, as well) perished. Consequently, the geographies of Africa’s national parks substantially correlate with areas of tsetse infestation. Without tsetse flies and the parasites they carry, much of Africa’s natural wonder may have been lost. It also means that tsetse flies may be among the wildlife encountered by park visitors.
Gina’s Story
We took our entire family on a three-week trip across East Africa, culminating in a tented safari in Serengeti National Park in the midst of the Great Migration. The best estimates of the migration are that it encompasses about two million wildebeest, half a million gazelle, and a quarter of a million zebra—almost three million large mammals in total. We spent a fortune to be placed in the midst of this spectacle. Only when we arrived, the plains were empty and quiet. Where were the animals?
While the wildebeest should have already reached our camp, their migration had been disrupted by “unseasonable rains.” The wildebeest were missing—but the tsetse flies were swarming in anticipation of their arrival. Maybe they were even angrier than normal, furious that their food was running late. Our family’s arrival was the next best thing. We were effectively serving ourselves up as a tsetse fly appetizer.
Prior to this trip, we had been all over Africa and had rarely even seen a tsetse fly, much less been bitten by one. How can we be so sure? Because you definitely know when a tsetse fly bites you. The pain is sharp and shocking, rather like an immunization needle. None of us had ever felt anything quite like it.
As soon as the open Land Rover stopped, the tsetse flies were upon us. They were undeterred by our insect repellent. Khaki clothing also was supposed to help, but it made no difference whatsoever. Khaki pants or blue pants, the flies landed and bit. We responded with layers of clothing and scarves wrapped tightly around our necks and faces. Still the flies would land and probe, and wiggle their way under the garments—until they found a spot where their long pokers could suck our blood.
The only effective deterrent was physical vigilance. Our guides gave each of us a severed cow tail tied to the end of a stick. No further instructions were required. We waved and swatted whenever the swarms descended. If the flies could not land, they could not bite.
Being back at the camp was no better. Dinner was served outside, under the stars and gas lanterns. The tsetse flies may have been asleep by then, but thousands of other insects had just hatched from the unusual rains. By the time waiters placed our first course of pumpkin soup in front of us, its surface was covered with drowning winged bugs. The flickering lanterns on our table only attracted more of them. They turned the white tablecloths into a veritable horror movie, sending us running for the safety of our zippered tents.
After a day of this misery, we instructed our guide to drive us to the Great Migration—even though it was four hours away. The long drive was definitely worth it. The scale of the migration was so large that it cannot be adequately captured by a camera, or even the eyes. There are just so many animals. They moved across the plain in long, snaking lines that stretched from one end of the horizon to the other. Upon meeting a river crossing, the herds would pause, piling up on each other and growing in numbers, until the earliest arrivals were pushed into the river by the latecomers. Then they would spill rapidly across the water, swimming as fast as they could through gauntlets of hungry crocodiles. It was an awe-inspiring experience—and fortunately, without any flies, since they were happy to feed on the wildebeests.
African tourists are not routinely devoured by tsetse flies so I researched whether we should be worried about sleeping sickness. The International Association for Medical Assistance to Travelers states that “[c]ases of sleeping sickness continue to be reported in tourists, many have been in or near Serengeti.” Newspaper articles also describe sporadic cases of travelers returning from Serengeti National Park with sleeping sickness. Nonetheless, I was reassured to learn that the probability of contracting the disease was remote because only a small percentage of the flies actually carry the parasite.
We all returned home healthy, filled with memories of our participation in the Serengeti’s circle of life. We were more than observers. We had been, well—tsetse fly food.