Occurrence
African trypanosomiasis is confined to tropical Africa between
15° north latitude and 20° south latitude, or from north
of South Africa to south of Algeria, Libya, and Egypt. According
to WHO 45,000 cases of trypanosomiasis were reported in 1999,
however the actual prevalence of cases is estimated to be between
300,000 to 500,000.
Risk for Travelers
Tsetse flies inhabit rural areas only, living in the woodland
and thickets of the savannah and the dense vegetation along streams.
Although infection of international travelers was considered rare,
the number of cases in travelers, primarily to East African game
parks, has increased in recent years. Approximately 1 case per
year has been reported among U.S. travelers. Travelers visiting
game parks and remote areas should be advised to take precautions.
Travelers to urban areas are not at risk.
Clinical Presentation
Signs and symptoms are initially nonspecific (fever, skin lesions,
rash, edema, or lymphadenopathy); however, the infection progresses
to meningoencephalitis. Symptoms generally appear within 1 to
3 weeks of infection. East African trypanosomiasis is more acute
clinically, with earlier central nervous system involvement than
in the West African form of the disease. Untreated cases are eventually
fatal.
Prevention
No vaccine is available to prevent this disease. Tsetse flies
are attracted to moving vehicles and dark, contrasting colors.
They are not affected by insect repellents and can bite through
lightweight clothing. Areas of heavy infestation tend to be sporadically
distributed and are usually well known to local residents. Avoidance
of such areas is the best means of protection. Travelers at risk
should be advised to wear clothing of wrist and ankle length that
is made of medium-weight fabric in neutral colors that blend with
the background environment.
Treatment
Travelers who sustain tsetse fly bites and become ill with high
fever or other manifestations of African trypanosomiasis should
be advised to seek early medical attention. The infection can
usually be cured by an appropriate course of anti-trypanosomal
therapy. Pentamidine isethionate (approved by the FDA, but considered
investigational for this purpose) and suramin (under an investigational
New Drug Protocol from the CDC Drug Service) are the drugs of
choice to treat the hemolymphatic stage of West and East African
trypanosomiasis, respectively. Melarsoprol is the drug of choice
for late disease with central nervous system involvement (infections
by T.b. gambiense or T.b. rhodesiense. Travelers should be advised
to consult an infectious disease or tropical medicine specialist.
— Anne Moore
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