Molecular detection of Toxoplasma gondii and Sarcocystis spp. co-infection in Tunisian Merguez, a traditional processed sausage beef meat

With the increase of raw food consumption, there is a growing interest in the risk posed by zoonotic infections to human health. This study was performed to identify in popular processed beef meat-based sausages (Merguez) the prevalence of Toxoplasma gondii and the zoonotic species of Sarcocystis. A total of 99 samples, collected from four Tunisian regions, were used for molecular analyses. For each sample, DNA was extracted from 4 equal pieces and PCR reactions were performed. Phylogenetic analyses were performed to identify Sarcocystis species. Prevalences of T. gondii and Sarcocystis spp. DNA in Merguez samples were 47.5% (95% CI: 0.38–0.57) and 52.5% (95% CI: 0.43–0.62), respectively. Important differences between regions were found. The DNA of both parasites was detected in 14.1% of the same samples. For Sarcocystis spp. infection, the percentage of samples having one positive piece was significantly higher than those having two, three or four positive pieces. Whereas, for T. gondii, the majority of tested samples had two positive pieces (16.2%) (p = 0.002). Sequencing showed the presence of Sarcocystis tenella and Sarcocystis cruzi species. Our findings suggest a high prevalence of T. gondii and Sarcocystis spp. in Merguez sausages with a potential high human health risk if the latter are undercooked.