Current status of food-borne parasitic zoonoses in Singapore

Parasitic infections adopt a rather low profile in the highly urbanized setting in Singapore. Very few food-borne parasitic infections are encountered. Apart from a few reports of infections with Clonorchis/Opisthorchis, Taenia spp. and hydatid disease, there are no other citations of such helminthic infections. Seroprevalence surveys have shown the presence of toxoplasmosis in local meat animals (sheep, pigs and cattle) and Toxoplasma strains have been isolated from the pig, tree shrew (Tupaia glis), slow loris (Nycticebus coucang) and guinea pigs. Human toxoplasmosis is prevalent in Singapore. Anti-Toxoplasma antibodies are found in the normal population as well as in clinical cases (cervical lymphadenopathy, ocular disease and congenital toxoplasmosis). Carcasses/organs from meat animals (sheep, pigs, cattle) slaughtered at local abattoirs were examined for parasites. The main parasites found were Ascaris suum, Dictyocaulus, Metastrongylus, Cysticercus ovis, Fasciola hepatica and Sarcocystis spp. Pigs were also examined for trichinosis and, thus far, these have all been negative.