Seroepidemiological study of ovine toxoplasmosis in East and West Shewa Zones of Oromia Regional State, Central Ethiopia

BACKGROUND: Toxoplasmosis is a globally distributed zoonosis. Consumption of raw or undercooked meat, which is among the main risk factors for acquiring human infection, is a popular tradition in Ethiopia. However, studies on toxoplasmosis in food animals used for human consumption in Ethiopia are very scarce. Thus, the objectives of the present study were to estimate the seroprevalence and the risk factors of T. gondii infection in sheep in Ambo, Ada’a-Liben and Fentale districts of Central Ethiopia. Sera from 1130 sheep were analyzed for Toxoplasma gondii specific IgG antibodies using an indirect enzyme linked immunosorbent assay (ELISA) with the P30 antigen. A questionnaire was administered to assess potential risk factors for T. gondii seropositivity. Association of seroprevalence with potential risk factors related to altitude, host and farm characteristics were analyzed by univariable and multivariable logistic regression. RESULTS: Overall flock and animal level seroprevalences were 70.48% (160/227; 95% CI: 64.51, 76.46) and 31.59% (357/1130; 95% CI: 28.88, 34.31), respectively. The multivariable logistic regression model indicated that the probability of acquiring T. gondii was higher in sheep from highland (2300 – 3200 meters above sea level) [Odds ratio (OR) = 4.11, 95% confidence interval (CI): 2.65, 6.36; P < 0.001] and midland (OR = 4.54, 95% CI: 2.76, 7.49; P < 0.001) than from lowland (<1500 meters above sea level), in females than in males (OR = 1.60, 95% CI: 1.04, 2.43, P = 0.033), in adult than in young animals (OR = 2.93, 95% CI: 1.97, 4.35, P < 0.001), in small than in large flocks (OR = 3.34, 95% CI: 1.26, 8.86, P = 0.016), and in sheep that were given tap water (OR = 4.07, 95% CI: 1.07, 15.42, P = 0.039) and river water (OR = 4.18, 95% CI: 1.54, 11.35, P = 0.005) than in those that drunk water from mixed sources (i.e., river, well, lake and pond). CONCLUSIONS: The high flock and animal level seroprevalence of toxoplasmosis in sheep is a good marker of the potential risk for human infections. Altitude, sex, age, flock size and source of water were identified as important risk factors to acquire the infection. Public education and awareness training are imperative in order to alleviate the danger posed to consumers. Further detailed studies to assess the impact of infections are warranted.