The epidemiology of trypanosomiasis in Rumphi district, Malawi: a ten year retrospective study.

BACKGROUND

Human African Trypanosomiasis (HAT) is caused by two species of the tsetse fly vectored protozoan hemoflagellates belonging to Trypanosma brucei, namely T.b gambiense which predominates in Western Africa and follows a chronic disease course and T.b rhodensiense which is more prevalent in Southern and Eastern Africa, Malawi included, and follows a more acute and aggressive disease course. Previous studies in the Democratic Republic of Congo, Angola, Uganda and Sudan have demonstrated that the prevalence rates of T.b rhodensiense infection have reached epidemic proportions.

OBJECTIVE

To describe the epidemiology of Trypanosomiasis in Rumphi District over the past ten years.

METHODS

A total of 163 records from January 2000 to December 2006 were retrospectively studied.

RESULTS

There were more males than females (121 vs. 40) with the 20 - 29 years age bracket having the highest number of cases (26.3%, n = 160). Stage 2 HAT was the commonest stage at presentation (58.2%, n = 158) with the patients in the same being 3.5 times more likely to die than those with stage 1 HAT. Case fatality rates for late and early stage disease were 21.5% (n = 92) and 7.2% (n = 66) respectively with 84.6% having been cured (n = 162). Convulsions were associated with fatal disease outcome and the majority of cases (97.2%, n = 103) lived within 5 kilometres of the Vwaza game reserve boundary.

CONCLUSIONS

More men have been infected than women, with a high involvement in the 20 - 29 age brackets. A dramatic increase with active case finding indicates a high under-detection of the disease with late stage HAT being predominant at presentation. Though it has been found that cases with late stage disease have an increased likelihood of dying compared to those in early stage HAT, the high proportion of successful treatment indicates that the disease still carries a high degree of favourable outcome with treatment. It has also been demonstrated in this study that more than 95% of trypanosomiasis cases live within 5 km of game reserve boundary. Disease interventions should be implemented in areas within 5 km of marshland game reserve boundary as priority areas.