Congenital infection of rabbits with Schistosoma japonicum and protective immunity of offspring

Recently congenital infection with Schistosoma japonicum (S. japonicum) has been demonstrated in pigs, rabbits, mice and dogs. We explored the rabbit as an animal model for the congenital infection of schistosomiasis japonica and assessed the effect of a congenital S. japonicum infection on the resistance of rabbit kittens to a postnatal challenge infection. Sixteen pregnant New Zealand white rabbits were infected with a single dose of S. japonicum cercariae. The exposed animals were divided into three groups according to the gestation age at the time of infection. Diagnosis of prenatally acquired S. japonicum infection in the rabbit kittens was primarily based on serological tests in combination with parasitological and histopathological findings. Congenitally infected kittens were challenged percutaneously with 100 S. japonicum cercariae to assess the effect of a congenital S. japonicum infection on kitten resistance to a postnatal challenge infection. The overall prevalence of congenital infection in offspring of infected mothers was 20% (12/60). The congenital infection rate in group L (late gestation) was much higher than in group E (early gestation) and group M (mid-gestation) (P