Longevity of Echinostoma caproni in Balb/c mice.

This study used Balb/c mice to examine the longevity of Echinostoma caproni. Five mice each exposed to 75 encysted metacercariae (cysts) were necropsied at 23 weeks postinfection (PI) (160 days PI). Two of the 5 were infected with a total of 33 worms; 23 in one mouse and 10 in the other. Body and organ area measurements showed that these worms were robust and normal in appearance. No signs of atrophy of any of the genital structures were observed. The mean +/- SE of eggs/uterus per worm (n = 10) was 243 +/- 6. This strain of mouse will be suitable to study the effect of long-term survival on the host-parasite relationship of E. caproni in Balb/c mice.