Blastocystis sp. from food animals in India.

Blastocystis, a zoonotic protozoan found in the intestinal tracts of a wide range of animals, has not been reported from non-human hosts from India so far. Organisms indistinguishable from Blastocystis sp. were identified in the Giemsa stained intestinal scrapings collected from carcasses of piglet and poultry that were brought for necropsy to the Central University Laboratory, Chennai. The 'central vacuole forms' of the parasite, with number of nuclei ranging from 1 to 12 were identified. The intensity of infection was low, with less than one organism per oil immersion field, indicating that their presence was unconnected to the cause of death. Caecal scraping was found to be more ideal than duodenal scraping for the diagnosis of Blastocystis, and can be a potential specimen for definitive diagnosis. Identical organisms were also detected in the dung samples of a buffalo calf which showed clinical signs of diarrhoea The presence of Blastocystis in food animals acquires public health significance, as many subtypes of the parasite from poultry and pigs are transmissible to humans.