The foodborne illness is contracted from undercooked meats as well as soil contaminated with cat faeces. Infections hospitalize 4,000 people and kill 300 every year in the US.
The study stated that a rise in toxoplasmosis cases can be attributed to increased consumption of free-range and organically raised meat because free-range and organic animals are more likely to forage and come into contact with cat droppings, which carry the parasite.
The USA has seen an increase in organic and free-range pork sales of about 20% each year since 1990. The USA organic programme standards require all animals to have access to outdoor space, including pasture.
Access to grass, soil, feed or water, contaminated with cat faeces or rodents and wildlife infected with toxoplasmosis, increases the risk of exposure to pigs and other livestock, the study reported.
Foodborne transmissions of the illness can be prevented by cooking meat correctly, as well as washing fruit and vegetables thoroughly before eating, the report's authors stated.