Eco-epidemiology of porcine trypanosomosis in Karim Lamido, Nigeria: prevalence, seasonal distribution, tsetse density and infection rates

BACKGROUND: Animal trypanosomosis is a major economic disease in Nigeria causing considerable morbidity and mortality in livestock. Despite reports in other animals, the disease is under reported in pigs. METHODS: We conducted a community based epidemiological study on African animal trypanosomosis in Karim Lamido area of Taraba State, Nigeria using species-specific PCR on 712 pigs and 706 of the 2822 captured tsetse flies. Data were analysed using Chi-square, odds ratio and multivariate analysis at 95 % confidence interval. RESULTS: Overall prevalence of porcine trypanosomosis was 16.6 % and ranged between 2.0 and 8.8 % across Trypanosoma species. Seasonal distribution of porcine trypanosomosis varied significantly (χ(2) = 16.62, df = 3, P = 0.0008) ranging between 7.9 and 23.6 % across seasons. Mixed infections involving T. b. brucei, T. congolense forest and T. congolense savannah recorded infection rates ranging between 2.5 and 9.3 %. There were significant variations between the trypanosome infection rates in relation to age (χ(2) = 7.629, df = 1, P = 0.0057, OR = 1.932, 95 % CI = 1.203–3.100), sex (χ(2) = 10.09, df = 1, P = 0.0015, OR = 2.085, 95 % CI = 1.315–3.304) and body condition (χ(2) = 22.10, df = 2, P < 0.0001) of pigs ranging between 10.4 and 30.3 %. Tsetse infection rates were 11.2 % (79/706) for Glossina palpalis and 6.8 % (48/706) for G. tachinoides yielding an overall infection rate of 18.0 %. CONCLUSION: Trypanosoma species are prevalent in the study area with similar distribution patterns in both pigs and tsetse flies. Late rainy season, adults, females and pigs with poor body condition recorded higher trypanosome infection rates. Of the three Trypanosoma spp. identified, T. b. brucei showed predominance.