Distribution and Incidence
An estimated 50 million people in 42 countries are at risk for trypanosomal infection (Molyneux and Smith, personal communication), while it is estimated that only about 5 to 10 million people have access to some form of protection against or treatment for the disease (World Health Organization 1985).
Sleeping sickness is endemic across the wide band of sub-Saharan Africa known as the “tsetse belt” lying roughly between 20o north and 20o south of the equator (see Maps VIIL2.1 and VIIL2.2), where it can attain epidemic proportions for a variety of natural and sociopolitical reasons.The actual numbers of cases will never be known, as it is a disease of remote rural areas, and even today people in such places often die undiagnosed and uncounted. Most national statistics are grossly underreported, with the World Health Organization being notified of about only 10 percent of the new cases. Based upon data from reporting countries, the current estimate of incidence is 20,000 to 25,000 cases annually, which is alarming because most of the victims are concentrated in Zaire, Uganda, and southern Sudan, the most important foci of the disease in the 1980s. In 1987, Busoga (Uganda) reported around 7,000 new cases, whereas the same region reported 8,500 to 9,000 cases in 1979-80. Some villages had infection rates of up to 25 percent (Smith, personal communication). In the late 1970s and 1980s, severe outbreaks occurred in Cameroon, Angola, Central African Republic, the Ivory Coast, Tanzania, as well as the Sudan, Zambia, Uganda, and Zaire.