Africa - Tsetse Flies

Africa - Tsetse Flies There are 22 different species of tsetse fly, and they live only in Africa. These flies are slightly larger than a horsefly. They breed along rivers and streams. They are active during the day and feed exclusively on blood. Unlike most biting flies where only the female feeds on blood, both male and female tsetse flies are blood suckers.

Tsetse flies are an enormous health risk in parts of Africa. They can transmit a disease called trypanosomiasis, an infection of the central nervous system. There are 2 forms of trypanosomiasis: Rodesian (sometimes called East African trypanosomiasis) and Gambian (sometimes called West African trypanosomiasis). Rhodesian trypanosomiasis, also known as nagana, is transmitted from animal to animal and mostly affects cattle, horses, and wild animals like antelope--although humans can also be infected. The Gambian form is much more prevalent and only affects humans. It is commonly called sleeping sickness.

Tsetse flies transmit nagana and sleeping sickness through their saliva. They first bite an animal or person that is already infected with a tiny microorganism called a trypanosome. This parasite lives inside the tsetse fly's stomach for several days and then travels to its salivary glands. After that, anyone or anything bitten by the fly becomes infected.

Tsetse flies are hard to control, and tsetse fly infestation is becoming more and more serious in Africa. The clearing of large forest tracks sometimes causes the fly to spread to more populated areas. The political unrest in many parts of Africa hampers pesticide control of this pest, as well.

Tsetse flies produce their young in a different manner than most flies. The female lays a single egg but keeps it inside her. It hatches into a maggot inside her body. It grows larger and larger as the female feeds on the blood of mammals. When the maggot fills its mother's abdomen, she releases it into the soil. It burrows and pupates immediately.

Visit the following websites and complete the activities.

African Trypanosomiasis - Summary Information

A tsetse fly can drink twice its weight in blood at every meal.

Describe the symptoms of sleeping sickness.
What is the usual outcome for people who get sleeping sickness and do not receive treatment for it?

African Trypanosomiasis

Some of the species of tsetse flies affect humans, but many other species affect only cattle and other livestock. In a bad year, sickness caused by tsetse flies can kill 100% of a herd.

List some of the countries in Africa that are affected by the tsetse fly.
If you were travelling to an area in Africa where sleeping sickness occurs, what could you do to protect yourself?

Fighting Flies With Flies

There are a minimum of 20,000 new cases of sleeping sickness each year throughout Africa.

What is one method for controlling tsetse flies that has proven successful in parts of Africa?

Spotlight Brian Hursey

Sleeping sickness is sometimes mistakenly considered to be a disease of the past, but its prevalence is actually increasing in many areas of Africa.

This is the transcript of a previous online chat with the coordinator of PAAT (Programme Against African Trypanonosomiasis). According this him, "Trypanosomiasis is the only animal disease that completely determines where and how people grow food." Explain.

Earthbeat : Tsetse Fly

It may seem like a simple issue--just use whatever methods necessary to reduce the numbers of tsetse flies so that much needed development can move ahead in some of the heavily affected African countries. But, surprisingly, conservationists claim that tsetse fly infestatation can benefit Africa. Find out why.

According to viewpoint of this article, what is the "down" side to controlling tsetse flies?

The African Trypanosomiasis

This disease is called sleeping sickness because in the advanced stages, when the trypanosomes have invaded the central nervous system, the victim is mostly comotose and soon falls into a coma and dies.

This site claims that sleeping sickness is a daily threat to how many people? (This doesn't mean that this many people actually HAVE sleeping sickness--it means that the possibility of exposure exists for this many people.)
In about how many countries does the threat of sleeping sickness exist?

Author: LINDA MOSBACKER - Email linda.mosbacker@slc.k12.ut.us