Serological and molecular detection of Toxoplasma gondii in chickens in southern Syria

Toxoplasma gondii is a foodborne protozoan parasite that infects all warm-blooded animals and humans worldwide. Poultry become infected with T. gondii oocysts by ground feeding, and humans contract toxoplasmosis by the consumption of raw or undercooked infected meat. In Syria, no research has been documented regarding T. gondii infection in chickens; therefore, this study was carried out to determine the infection rate in chickens using serological and molecular assays. A total of 59 birds (50 females and 9 males) including free range (FR) and caged chickens were purchased from the southern governorates of Syria. Blood and tissues (brain, heart, liver and pectoral muscle) were collected and analyzed for the presence of anti-T. gondii antibodies and parasite DNA by indirect hemagglutination test and semi-nested PCR, respectively. Overall, sero-positivity for T. gondii antibody was 72.9% (81.4% FR and 18.6% caged). Female chickens had higher prevalence than males (83.7% vs 16.3%). Furthermore, chickens older than six months showed higher infection rates compared to younger ones. Evidence of T. gondii DNA was detected in tissue homogenates from both groups of chickens (83.1%). Our study demonstrates, a high prevalence of T. gondii in chickens indicating that this parasite poses a threat to food safety and public health in our study area. This finding supports the recommendations that poultry meat should be cooked well before consumption and appropriate hygiene measures should be followed when handling meat. Further studies should be conducted to determine the prevalence of T. gondii and its genotypes in poultry in other regions of Syria and to identify the associated risk factors.