The public health importance of African trypanosomiasis in north east Zambia.

A survey for sleeping sickness (Trypanosoma brucei rhodesiense) in villages in the northern Luangwa valley found a point prevalence of parasitaemia of 5.8 per thousand; the incidence of the disease was estimated at about 1% per annum. None of the cases found had sought treatment and pre-symptomatic cases may represent an important reservoir of infection to others. Other frequent parasitemias in the population included malaria (P. falciparum, P. malariae and P. ovale) which is hyperendemic and Dipetalonema perstans.