Prevalence and risk factors of bovine trypanosomosis in Kilwa district, Lindi region of southern Tanzania.

African animal trypanosomosis (AAT) and human African trypanosomosis (HAT) are complex chronic, debilitating, emaciating and often fatal diseases of animals and humans, respectively. This cross-sectional study was conducted to determine the prevalence and risk factors associated with bovine trypanosomosis in tsetse-infested Kilwa district, Lindi region, southern Tanzania. Blood samples were collected from 420 cattle randomly selected from 86 herds from ten villages. A maximum of ten herds per village and at most six animals from each herd were selected for sampling. At the same time, a questionnaire was administered. Individual animal samples were analysed using microscopy and pooled sample at herd level were analysed by loop mediated isothermal amplification (LAMP). A herd was considered positive if at least one animal in the herd was positive for AAT. A prevalence of 9.3% (95% CI: 2.9-14.9) was recorded for AAT by microscopy, mainly caused by Trypanosoma congolense (5.8%, 95% CI=0.9-10.7), Trypanosoma brucei species (5.8%, 95%, CI=0.9-10.7) and Trypanosoma vivax (3.5%, 95% CI=0-7.4). Loop mediated isothermal amplification (LAMP) recorded a heard prevalence of 41.9% (95% CI: 30.0-51.4%), mainly caused by T. congolense (30.2%, 95% CI: 20.5-39.9), T. brucei species (25.6%, 95% CI: 16.4-34.8) and T. vivax (20.9%, 95% CI: 12.3-29.7). Most of the cattle herds had mixed infections of these parasites. According to LAMP, Miteja and Matandu villages had the highest AAT herd prevalence of 57% (95% CI: 20.3-93.7) while Mavuji had the lowest prevalence of 14% (95% CI: 0-39.7). Data from the present study suggest that district of origin, grazing in game reserve, water source and form of watering point are risk factors associated with AAT in Kilwa district, southern Tanzania. Continuous surveillance and monitoring of AAT using more sensitive are recommended.