African sleeping sickness
African sleeping sickness or African typanosomiasis is found
in West, Central, and East Africa, confined between 15 degrees
North and 20 degrees South latitude.
The disease is caused by infection with a protozoal parasite
transmitted by the bite of an infected tsetse fly. They pass it
on by biting large, warm-blooded animals and are responsible for
the lack of horses and cows in some areas. The tsetse fly is about
twice the size of a housefly or about the size of a honeybee,
and recognizable by the scissor-like way it folds its wings when
at rest. Only a small proportion of tsetse flies carry the disease
but it is best to try to avoid being bitten. The tsetse fly bites
during the day.
Although the risk to international travelers is relatively
low, persons traveling to game parks and sparsely inhabited areas
should take precautions. Tsetse flies appear to be attracted to
moving vehicles, dark, contrasting colors, perfume, and aftershave
lotions. The flies are capable of biting through lighter weight
clothing. Areas of heavy infestation tend to be sporadically distributed
and are usually well known to local inhabitants. Avoidance of
such areas is the best means of prevention. Travelers at risk
should use "DEET" containing insect repellents liberally
and wear clothing of wrist and ankle length that blends with the
background environment and is constructed of heavy, e.g., canvas
The incubation period of acute trypanosomiasis ranges from
6 to 28 days, and travelers frequently become ill during their
trips or shortly after returning home. Swelling at the site of
the bite, five or more days later, is the first sign of infection.
This is followed within two to three weeks by rash, fever, headaches,
lethargy, confusion, and severe illness. The illness is serious
but responds well to medical attention.
Chronic trypanosomiasis may not cause symptoms until months
to years following travel to an endemic area,
No vaccine is available.