Predators I Have Known - Alan Dean Foster [64]
African trypanosomiasis is far less benign than the name it is commonly known by: sleeping sickness.
Besides obliterating cattle by the herd, this exceedingly unpleasant affliction was for many years the number-one cause of death among the human population in some parts of Africa. Once infected, a person begins to suffer fever, headache, and joint pain. Swelling of the lymph nodes, sometimes to prodigious size, follows. Left untreated, the disease spreads throughout the body and methodically overwhelms its defenses. It starts to affect the brain, manifesting itself in bouts of confusion and a complete disruption of the normal sleep cycle, which leads eventually to coma and death. Survivors often suffer permanent neurological damage, including at least one variety of Parkinson’s disease. The disease is caused by the introduction of the protozoan Trypanosoma, into the bloodstream of cattle and humans. The protozoan itself is transmitted to cattle and their herders by the tsetse fly.
If sleeping sickness is a benign malady, give me malaria.
Having read about Africa all my life, I had naturally come across innumerable references to the tsetse fly and to sleeping sickness. So it was with some trepidation that when preparing to visit East Africa for the first time, I wrote our friend and host Bill Smythe to ask about whether or not the disease was present in any of the areas where we intended to travel.
“Plenty of tsetse flies,” Bill replied, “but very little trypanosomiasis.”
Good enough—I was half reassured. We booked our plane tickets.
Having driven through east and southern Tanzania for weeks without encountering the fabled vectors, we had grown somewhat complacent regarding the threat they posed. It was not until we headed north and found ourselves in the forest around Lake Manyara that they began to make their presence known—and to remind us why entire sections of Africa remain to this day unable to support herdsmen and their cattle.
We had stopped the car to watch a huge troop of baboons playing, feeding, and generally acting like primates. To conserve hard-to-obtain fuel, we had the air-conditioner off and the windows rolled down. Had any of the baboons approached too closely, we would have swiftly rolled them back up. Baboons are notorious for invading cars and making off with anything they can lay their hands on. But since we were off the beaten tourist track, this particular large troop was unsure of us. They had not yet learned that humans in cars can be a source of food and entertainment.
Suddenly, Sally Smythe let out a yelp of pain, and we all immediately looked in her direction.
“Tsetse fly,” she declared unhappily. A moment later, JoAnn echoed our friend’s exclamation. We immediately started rolling up windows—and embarking on a frenzied program of highly localized extermination.
We couldn’t roll the windows down to shoo the flies out because that would only let more of them in. That was when I discovered that the tsetse fly is very likely the most intelligent and deceptive member of the fly family. It is certainly the toughest.
They’re not hard to see. About the size of a common large housefly, they are the same bland gray in color; the better to blend in with any background, no doubt. They are also the possums of the fly world. Swat a tsetse fly, and it will fall off you, lie on the ground (or in this case the floor of the car) and play dead. Look away, and this Lazarusian insect immediately returns to the attack.
And it is just that, an attack. Even the vicious horsefly of the western United States takes a moment or two to evaluate its meal before dining, going for a stroll on its unsuspecting quarry while searching for a suitable place to dig in. The tsetse is far less discriminating. It doesn’t land on you so much as it dives, needlelike