The occurrence of porcine Toxoplasma gondii infections in smallholder production systems in Uganda

Abstract

Pig production is an emerging agribusiness in Eastern Africa but baseline information on pig diseases including zoonoses is still scarce. Infection with Toxoplasma gondii does not usually present with clinical signs in pigs, yet it is considered an important source of human infection when pork containing tissue cysts is poorly handled or consumed raw or undercooked. In a cross-sectional survey between April and July 2013, we sampled 932 pigs between three months to three years of age in 22 villages at smallholder farms. The sera were tested for the presence of antibodies to T. gondii using a commercial ELISA (PrioCHECK Toxoplasma Ab porcine) and an in-house assay (TgSAG1 p30). The overall seroprevalence based on the commercial ELISA was 28.7% (95% CI: 25.8-31.7%). Seropositive animals were found in all villages with significant differences across the three districts (P<0.05) and 12 sub-counties (P<0.01) in the survey area. Cohen’s kappa statistic showed a very good level of agreement (κ=0.7637) between the two serological assays. Preliminary univariate analysis suggests a significant association between seropositivity and pig age, value chain type, feeding of crop residues, source of drinking water, keeping cats on farm compound, and frequent sightings of wildlife (especially antelopes, hares, wild and stray dogs) near the village. The present report is the first survey documenting the seroprevalence of T. gondii in domestic pigs in the East African Community (Burundi, Kenya, Rwanda, Tanzania and Uganda) and investigating potential risk factors that may need attention when promoting smallholder pig keeping as a livelihood activity in Central and Eastern Uganda. The research was carried out with the financial support of the Federal Ministry for Economic Cooperation and Development, Germany, the CGIAR Research Program on Agriculture for Nutrition and Health, led by the International Food Policy Research Institute, through the Safe Food, Fair Food project at ILRI as well as the CGIAR Research Program on Livestock & Fish at ILRI as part of the Smallholder Pig Value Chain Development Project.