Abstract:

Apparent density, Infection rates and host preferences are among the factors which are important in understanding the epidemiology of vector borne diseases and their control. A study was undertaken in the communal grazing lands of three districts in Mid-Northern Uganda to investigate the status of tsetse fly population. Tsetse apparent densities varied between 0.2-2.1 flies/trap/day across the three study areas and Glossina fuscipes fuscipes was the only species encountered. Tsetse flies were trapped, dissected and their organs (proboscis, salivary glands and mid-guts) were microscopically examined for trypanosome infections giving an overall infection rate of 5.6%. Out of the 376 non-teneral flies dissected and examined microscopically for infections, trypanosomes of various species were observed in 21 flies. Of the infected flies, 17 (81%) were females while 4(19%) were males, which constituted a statistically significant difference (x2, 8.048, d.f.= 1, P= 0.002). The infection rates were high during the wet season 3.7% than the dry season 1.9%. The infecting rate of trypanosome species were classified as 3.2% for T.vivax, 1.3% for T.congolense, 1.1% for immature (gut only) and 0% for T.brucei. Although the proportion of T.vivax (3.2%) was higher than that of T.congolense (1.3%), there was no significant difference between the two (x , 2.882, d.f.— 1, P- 0.04). Bloodmeal analysis implicated two(2) vertebrate hosts, cattle and human beings. This finding is of epidemiological importance, in relation to the cycle of transmission of human infective trypanosomes between domestic animals and man an implication that control efforts of trypanosomosis should priotise on these two hosts.