Prevalence, Genetic Diversity, Tissue Distribution, and Risk Factors Contributing to T. gondii Burden in Domestic Pigs

Abstract

Toxoplasma gondii is an obligatory intracellular parasite of mammals, including humans and domestic animals. The infection with this parasite has severe clinical consequences, as it causes abortion or fetal abnormalities, encephalitis in immunocompromised humans, ocular toxoplasmosis with chorioretinitis, and it may contribute to Alzheimer disease. Therefore, an efficient control of T. gondii by prevention of the transmission to humans is strongly recommended. Pork is considered as an important source of toxoplasmosis, due to the frequent consumption of the raw or undercooked porcine meat products, a high susceptibility of pigs to the infection, and because of the numerous risk factors, contributing to the prevalence of toxoplasmosis in the pig population. The cellular and humoral immune responses, such as IgM, IgG, IFN-gamma, and interleukin-10 or -12 production, associated with the acute and chronic infection in pigs, do not prevent development of the tissue cysts, which persist lifelong within the intermediate host. Therefore, the prevalence of T. gondii in the pig population might be an useful indication of the risk associated with the consumption of the porcine meat.