Trypanosome infections in Glossina spp. inhabiting peridomestic agroecosystems in Nsukka area, Anambra State, Nigeria.

Trypanosome infections in Glossina spp. inhabiting three peridomestic agroecosystems in Nsukka area were studied by dissection from April 1984 to July 1985. Approximately 0.65% of 4620 G. tachinoides and none of 17 G. palpalis were found with maturing or mature trypanosome infections. Of these infections, 20% were due to the Trypanosoma brucei group, 40% to the T. congolense group, and 40% to a mixture of the T. brucei and T. congolense groups. Trypanosome infection rates did not differ significantly with seasons or sex of fly, but they differed significantly with location. An apparent difference was observed in the frequency with which male and female G. tachinoides were infected by the various trypanosome species. Also there was a difference in the variety of trypanosome species encountered in the three locations. In infective flies, while the salivary gland, labrum and midgut were scantily to very heavily infected, the hypopharynx was never heavily infected. Dependence of tsetse flies on domestic pigs as the major source of blood meals, commercial activities in the area, the inherently limited vectorial capacity of palpalis group tsetse, and the fact that most flies apparently obtained their first blood meal when two to four days old, were identified as some of the factors responsible for the observed infection rates. The epizootiological and epidemiological implications of these findings are discussed.