Survey of Toxoplasma gondii in Taipei: Livestock Meats, Internal Organs, Cat and Dog Sera

Toxoplasma gondii (T. gondii) is an important food-borne zoonotic protozoa. Infection occurs when humans and warm-blooded animals consume raw or lightly cooked cysts containing meat or speculated oocysts contaminated food. T. gondii infection has been observed in food animals in many countries suggesting the significance of food animals in the epidemiology of toxoplasmosis. However, there is no report regarding T. gondii infection in food animals other than pigs in Taiwan. Therefore, in this study, pork, pig livers, mutton, chicken flesh, chicken hearts, chicken livers, gizzards, and imported beef sold in the supermarkets in Taipei were examined for T. gondii deoxyribonucleic acid (DNA) by polymerase chain reaction (PCR), for T. gondii antigens by enzyme-linked immunosorbent assay (ELISA) and for cysts by microscopy. Because T. gondii infected cats may shed oocysts in their feces and the mechanical spread of T. gondii to humans can also be conducted by dogs, serosurvey was also conducted on cats and dogs. The results showed that the prevalence of T. gondii DNA were 8% in pork, 2% in pig liver, 4% in mutton, 4% in chicken flesh, 2% in chicken heart, and 5% in imported beef. However, T. gondii antigens were not detected in all samples and cysts were not found in DNA positive samples. The seroprevalence of antibodies to T. gondii in cats and dogs were 10% and 6% respectively which are not significantly different from those reported in the year 1998. This is the first survey on T. gondii in livestock meats and internal organs in Taipei.