Washington: Italian scientists have found an intestinal parasite that causes diarrhoea in humans also makes its home in pigs, a discovery they say could help understand its transmission better and lead to effective treatments.
The existence of the single-celled parasite, Dientamoeba fragilis, in pigs is important because it might mean pig feces are one way the parasite has been spreading to humans, said researchers at the Istituto Superiore di Sanita in Rome.
More than a billion pigs are housed in farms across the world. In developing countries, where waste disposal is poor, D fragilis infection rates in people hover between 19 per cent and 69 per cent.
Travellers to these countries also often fall prey to the parasite. Infection is sometimes asymptomatic, but it can also cause diarrhoea and abdominal pain, LiveScience reported.
Few animal hosts, or "reservoirs" for D fragilis had been discovered. As pigs in Italy were found having high infection rates, the scientists collected and analysed 152 fecal samples from nine farms.
They found that 52 of 74 piglets, 11 of 14 pigs at the "fattening" stage, and eight of 64 sows tested positive for D fragilis. Young animals appeared to be most susceptible.
Further analysis showed that the parasite found in pigs was the same one that infects humans, which means pigs could transmit the parasite to humans, likely through their waste, the researchers said.
The discovery could be a boon to understanding the parasite better, the researchers said. Little is known about D fragilis` life cycle, and pigs could provide a useful model for understanding how transmission and infection occurs, they added.
The study was published in journal Emerging Infectious Diseases.