Preliminary survey on tsetse flies and trypanosomosis at grazing fields and villages in and around the Nech Sar National Park, Southern Ethiopia

Abstract

Preliminary survey on tsetse flies and trypanosomosis were conducted between July and August 2007 in grazing fields and villages in and around the Nech Sar national park, with the ultimate intention of forwarding baseline information on the extent of the problem and possible control strategies. An entomological (Tsetse flies) survey was conducted by deploying a total of 16 georeferenced NGU traps on the grazing fields used by cattle. Parasitological (Trypanosomosis) survey and PCV (Packed Cell Volume) measurement were done on 202 randomly selected (zebu) cattle of the villages neighbouring the park. Glossina pallidipes, with mean apparent density of 11.46 ftd (flies per trap per day), was found to be the only prevailing tsetse fly species in the study area. The mean apparent density of tabanid flies (mechanical vectors) was found to be 4.54 ftd. Trypanosomosis, with a prevalence of 17.33±5.30 (35/202 cattle), was seen to be a serious problem of cattle in the area. Trypanosoma congolense (33 cases) was the dominant species encountered in the area, with 2 cases of T. vivax. The overall mean PCV was 17.65±5.30%. The mean PCV of the aparasitaemic and parasitaemic animals were found to be statistically significantly different (P0.05), but the number of cattle aparasitaemic but anaemic was also significant. This could be possibly due to infection by other recurrent parasites (such as haemonchosis, babesiosis and anaplasmosis), and nutritional deficiencies,. The present study indicated G. pallidipes to be the principal vector of trypanosomosis in the area. Thus, an urgent intervention with control mechanisms need to be adopted before the devastating impact of tsetse flies and trypanosomosis is aggravated to the extent of unbearable economic loss.