TrypanosomaInfection Rates inGlossinaSpecies in Mtito Andei Division, Makueni County, Kenya

Abstract

African Animal Trypanosomiasis (AAT) transmitted cyclically by tsetse fly (Glossinaspp.) is a major obstacle to livestock production in the tropical parts of Africa. The objective of this study was to determine the infection rates of trypanosomes inGlossinaspecies in Mtito Andei Division, Makueni County, Kenya. Tsetse fly species,G. longipennisandG. pallidipes, were trapped and DNA was isolated from their dissected internal organs (proboscis, salivary glands, and midguts). The DNA was then subjected to a nested PCR assay using internal transcribed spacer primers and individual trypanosome species were identified following agarose gel electrophoresis. Out of the 117 flies trapped in the area 39 (33.3%) were teneral while 78 (67%) were nonteneral.G. pallidipesconstituted the largest percentage of 58% whileG. longipenniswere 42%. The overall trypanosomes infection rate in all nonteneralGlossinaspp. was 11.53% withG. longipennisrecording the highest infection rate of 23.08% whileG. pallidipeshad an infection rate of 5.77%.T. vivaxwas the most infectious (10.26%) compared toT. congolense(1.28%). Mean apparent densities were strongly positively correlated with infection rates (r=0.95) confirming the importance of this parameter as an indicator of AAT transmission risk.