Abstract:
Eleven species/subspecies belonging to the genus Trypanosoma, cause African Animal Trypanosomiasis (AAT) with Trypanosoma vivax and Trypanosoma congolense being the predominant pathogens. Annually, AAT leads to losses worth 4.5 billion dollars to livestock dependent economies in Sub-Saharan Africa. In order to manage the disease, trypanocidal drugs have been in use. However, parasites resistant to these trypanocides have emerged making the treatment of AAT difficult. Parasite resistance to trypanocides is one among the few variable phenotypes whose genetic basis is poorly understood. There is need to create a link between the genetic component, environmental component and phenotypic manifestation of the parasite. Consequently, knowledge of genotypes/diversity of species helps create this link. In this study, the ecology, identity and genetics of trypanosomes circulating between bovine hosts and Glossina pallidipes in sites surrounding the Shimba hills game reserve, Kenya was considered. The Internally Transcribed locus (ITS1) of ribosomal DNA was targeted for amplification to identify different species of trypanosomes. Species specific amplification of minisatellite repeats was used to confirm the presence of T. congolense savannah detected using the ITS1 locus. Six out of the eleven trypanosome species that are detectable by PCR were found to be present in this area. This level of species diversity was observed for both cattle hosts and G. Pallidipes with T. congolense savannah being the dominant species. These findings will greatly influence future studies in this area, whereby either the vector or host will be used to source trypanosomes. A multiplex protocol for microsatellite genotyping was developed for T. congolense savannah, which is the most virulent trypanosome.
