Prevalence of Surra in Dromedary Camels in Uganda

Abstract

Three herds, comprising 112 camels, were sampled and examined for Trypanosoma evansi infection (surra) in Moroto district, north-eastern Uganda. The Micro-Haematocrit Centrifuge Technique (MHCT) was used for parasitological diagnosis, while Suratex® and Enzyme-Linked immunosorbent assay (ELISA) were used for trypanosome antigen and anti-trypanosomal antibody detection, respectively. The haematocrit level of each camel was determined during examination with MHCT. Parasite prevalence ranged from 0% to 47%, while Suratex® showed positivity ranging from 35% to 65%. A high antibody prevalence ranging from 78-100% was recorded by ELISA. Low haematocrit values were associated with parasite or antigen-positive camels. Preliminary characterization of 8 trypanosome isolates from these camels by microscopic examination of Giemsa-stained bloodstream forms, transformation in SM-77 medium and isoenzyme characterization, shows characteristics similar to Tripanosoma evansi, as evidenced from their monomorphism, failure to transform in procyclic medium and zymodeme profiles. These findings show a high prevalence of T. evansi infection in Ugandan camels which is associated with anaemia and calls for the institution of interventional measures to save these useful animals. This is the first report of the existence of T. evansi in Uganda, which could be of considerable consequence in the epidemiology of animal trypanosomosis in the country.