The distribution and epidemiology of bovine trypanosomosis in Malawi

A survey to update the distribution and clarify the epidemiology of bovine trypanosomosis in Malawi was conducted between 1995-97. Use was made of par asitological and serological (anti-trypanosomal antibody-detection Enzyme-L inked Immunosorbent Assay (ELISA) diagnostic methods. Trypanosomal infectio ns were detected in cattle sampled adjacent to known tsetse foci. The distr ibution of cattle with anti-trypanosomal antibodies indicated that the dist ribution of bovine trypanosomosis was more widespread than the parasitologi cal prevalence data suggested. This is attributed to the seasonal movement of tsetse (mainly Glossina morsitans morsitans and G. pallidipes) from its prime habitat and the presence of localized foci of G. brevipalpis. The odo ur-baited, insecticide-treated, target barriers along the edge of Kasungu N ational Park and the Nkhotakota Game Reserve appeared to be effective in pr eventing tsetse from moving outside the game areas and contacting cattle. The anti-trypanosomal antibody-detection ELISA proved to be a useful tool i n establishing the distribution of bovine trypanosomosis. Moreover, the dis tribution and prevalence of cattle with anti-trypanosomal antibodies was in strumental in clarifying the epidemiology of bovine trypanosomosis in Malaw i, The anti-trypanosomal antibody-detection ELISA had high sensitivity in d etecting Trypanosoma congolense infections. In parasitologically negative a nimals, the average packed cell volume was higher in those that had no anti -trypanosomal antibodies.:The packed cell volume decreased with increasing antibody titre. (C) 2000 Elsevier Science B.V. All rights reserved.