Tsetse and trypanosomiasis

Can I protect myself from being bitten?

While it might be hard to believe when you are frequently bitten by tsetse, several savanna species of tsetse are actually repelled by human odour (Vale, 1977b; Hargrove, 1976). However there are some further measures you can take to reduce the chance of being bitten.

First, you can follow the usual advice of wearing long trousers and clothes that cover your skin. You can also avoid being out in tsetse-infested areas in the late afternoon and early morning, when tsetse are most active. However, this advice is not particularly helpful if you are a tsetse entomologist who must be out and about!

Tsetse are also attracted to moving vehicles (Vale, 1974b). Consequently, if you drive slowly through heavily infested areas, large numbers of tsetse can enter the vehicle and bite the occupants. You might have experienced this when you slow down to cross a river; flies that are concentrated in the riverine vegetation will be attracted to the vehicle and enter. In these circumstances wind up the window of the car or fit the window with a netting screen.

During the hot season, tsetse enter refuges in the middle of the day to protect themselves from the heat (Torr & Hargrove, 1999). The best natural refuges are cool, dark hollows found in large trees. Houses and huts also provide a similarly cool environment and so large numbers of tsetse can enter buildings during the hot season. Flies would normally leave the refuge in the late afternoon to feed but those within a house can become trapped and feed on people within the house. In these circumstances, measures to either prevent tsetse from entering the building in the first place, or allowing them to leave easily would reduce the risk of being bitten.

Pastoralists living in tsetse-infested areas are not often bitten by tsetse. This is probably because people are almost always close to attractive hosts such as cattle, and in the late evening they often use woodsmoke to repel tsetse and other biting flies.

References
Hargrove, J.W. (1976) The effect of human presence on the behaviour of tsetse (Glossina spp.) (Diptera, Glossinidae) near a stationary ox. Bulletin of Entomological Research 66, 173-178.

Torr, S.J. & Hargrove, J.W. (1999). Behaviour of tsetse (Diptera : Glossinidae) during the hot season in Zimbabwe: the interaction of micro-climate and reproductive status. Bulletin of Entomological Research 89, 365-379.

Vale, G. A. (1974b). The response of tsetse flies (Diptera; Glossinidae) to mobile and stationary baits. Bulletin of Entomological Research 64, 545-587.

Vale, G.A. (1977b). Field responses of tsetse flies (Diptera: Glossinidae) to odours of men, lactic acid and carbon dioxide. Bulletin of Entomological Research 69, 459-467.