A review of toxoplasmosis in pigs.

Toxoplasma gondii infection is highly prevalent in pigs in most countries, but little is known of its epizootiology. Transplacental infection appears to be less common than post-natal infection. Most pigs acquire subclinical infection. Clinical toxoplasmosis occurs mostly in young pigs. The frequency of oocyst- vs tissue cyst-acquired infections is unknown. Why clinical toxoplasmosis is more prevalent in Japan than in other countries is puzzling and needs investigation. In experimentally infected pigs, tissue cysts persist in edible organs for several months. They persist longer in the brain, heart and tongue than in other tissues.