Infectivity, growth, survival, and pathogenicity of Zygocotyle lunata (Trematoda) in experimental rodent hosts.

Laboratory mice, rats, and golden hamsters were fed metacercarial cysts of Zygocotyle lunata to examine infectivity, growth, survival, and pathogenicity of this trematode. All 3 rodent types became infected with Z. lunata. Eggs of Z. lunata were seen in the feces of the hamsters by day 21, in mice by day 26, and in rats by day 44. Eggs teased from worms and embryonated in tap water hatched from day 21 to day 26 for rats and mice and from day 40 to day 45 for hamsters. The body areas of sexually mature worms were similar in all 3 types of rodent species. It was possible to reinfect all 3 species with Z. lunata metacercariae. No sign of clinical amphistomiasis was evident in the experimental animals. The histopathological responses were progressive, and severity was related to the age of the infection and the number of worms in the infection.