Experimental studies on vertical infection of mice with Japanese encephalitis virus. I. Effect of mouse strain on placental and fetal infection.

An experiment was carried out with mice to study the effect of the mouse strain on the establishment of experimental vertical infection with Japanese encephalitis virus. Mice of various inbred strains were inoculated with a field strain of virus on the 7th day of pregnancy. An attempt was made on them to recover the virus from the placenta and fetuses. As a result, there were differences in the rate of placental and fetal infection among the mouse strains used. It was clarified that vertical infection could be established experimentally in some selected mouse strains. There was not always a parallel relationship between the rate of placental and fetal infection and the severity of viremia or visceral infection in the dam.