Trichinella pseudospiralisovercomes innate resistance of the chinese hamster toTrichinella spiralis

Abstract

Infectivity ofTrichinella pseudospiralisin Chinese hamsters was greater than that ofTrichinella spiralis. Concurrent infection with these two species of parasite was accompanied by an increase in infectivity ofT. spiralis. The infectivity ofT. pseudospiralis, but not that ofT. spiralis, was significantly influenced by host age. Regardless of host age,T. pseudospiraliswas more infective for the Chinese hamster than wasT. spiralis. Early during infection, enteritis (myeloperoxidase activity) in hamsters infected withT. pseudospiralisalone was significantly less than that seen in animals infected withT. spiralisalone or with both species concurrently. Myositis in hamsters infected withT. pseudospiralisalone was significantly less on days 14, 17 and 25 post-infection (p.i.) than that observed in concurrently infected orT. spiralis-infected animals. On days 11 and 14 p.i. inflammation in diaphragm muscle from concurrently infected hamsters was significantly less than that seen in animals infected withT. spiralisalone. Muscle histology supported these chemical data on myositis. Suppression of the host inflammatory response against early muscle-stage larvae ofT. pseudospiralisunderlies the greater infectivity of this parasite for the Chinese hamster.