Molecular identification of pathogenic African trypanosome species in livestock from the southern part of Ethiopian Rift Valley.

Animal African trypanosomosis (AAT) continues to pose a major constraint to livestock productivity and socioeconomic development in sub-Saharan Africa. Despite its importance, data on trypanosome species as well as their prevalence in livestock in the southern Rift Valley of Ethiopia (SRVE) remains limited. This study aimed to determine the diversity and the prevalence of trypanosome species in livestock from six districts in the SRVE. Blood samples were collected from 725 animals including 548 cattle, 151 goats and 26 donkeys. Trypanosome infections were detected using the capillary tube centrifugation (CTC) technique and polymerase chain reaction (PCR) on DNA extracts from buffy coat. The overall prevalence of trypanosome infections was 4.5% (95%CI: 3.26-6.32%) by CTC and 8.1% (95% CI: 6.4-10.4) by PCR. This prevalence was 9.5% (95% CI: 7.3-12.2%) in cattle, 3.3% (95%CI: 1.1-7.5%) in goats and 7.7% (95%CI: 0.0-17.9) in donkeys. Three trypanosome species including Trypanosoma congolense (T. congolense savannah), T. vivax and trypanosomes of the subgenus Trypanozoon were detected in 4.3%, 4.3% and 0.3% of animals, respectively. The highest prevalence of trypanosome infections was recorded in the Kucha alpha district (32.3%, 95%CI = 22.0-44.6). Cattle from Kucha alpha and Hobicha Abaya had 20 and 4 times higher risk of acquiring trypanosome infections, respectively compared to those from Abela Abaya district. Significant associations were recorded between trypanosome infections with anemic animals as well as district like Kucha alpha. The risk of acquiring trypanosome infections varied according to animal taxa, trypanosome species and districts. Trypanosome infections were associated with some districts and anemic status of the animals. The identification of transmission hotspots suggests focused control strategies.