Seroprevalence, Risk Factors and Molecular Detection of Toxoplasma gondii in Sheep Slaughtered for Human Consumption...

Toxoplasma gondii is a zoonotic parasite of significant public health concern, particularly in regions where consumption of undercooked meat is common. Despite the importance of sheep as a potential source of human infection, understanding of T. gondii seroprevalence and tissue distribution in sheep in the Red Sea State in Sudan remains limited.

A cross-sectional study was conducted to investigate the seroprevalence and tissue distribution of T. gondii in sheep slaughtered for human consumption in Port Sudan and Tokar localities between February and August 2010. Serum samples were analysed using the Latex Agglutination Test (LAT) for initial screening due to its simplicity and cost-effectiveness, and IgG-captured ELISA to confirm LAT doubtful results, while tissue samples from systematically selected seropositive animals were examined using real-time PCR targeting the 529 bp repeat element to assess tissue distribution patterns.

A total of 700 sheep were tested for anti-T. gondii antibodies. The overall seroprevalence was 45.4% (318/700, 95% CI 41.8-49.1) by LAT, with 64% (57/89) of LAT-doubtful samples testing positive by IgG-captured ELISA. Multivariate analysis identified Etbawi eco-type (OR = 2.38, 95% CI 1.54-3.68, p = 0.001) and age > 2 years (OR = 2.45, 95% CI 1.17-5.14, p = 0.018) as significant risk factors. Real-time PCR detected T. gondii DNA in 16% (16/100) of tissue samples from seropositive sheep, with the highest positivity observed in brain (40%) samples. Notably, T. gondii DNA was detected exclusively in brain tissue in Port Sudan, while in Tokar, it was found in skeletal muscles, liver and diaphragm.

The high seroprevalence and molecular detection of T. gondii in edible tissues highlight a significant public health risk in the Red Sea State, particularly given local practices of consuming raw or undercooked meat. These findings emphasise the need for improved meat inspection and implementation of One Health approaches (e.g., integrated veterinary-public health surveillance systems) to reduce T. gondii transmission from sheep to humans despite the data being collected more than a decade ago.