Perinatal transmission of coxsackievirus B3 in mice.

Oral infection of pregnant mice with coxsackievirus B3 (CB3) late in gestation produced maternal viremia, which peaked three to four days after challenge, then rapidly diminished. Ninety percent of mice developed IgG antibody to CB3 by ten days after challenge. CB3 titers from placental tissue peaked at two to four days after maternal infection, but moderate titers persisted for at least eight days. Though virus could be recovered (less than 1.0-1.5 log10 pfu/g) from fetal tissue in only a small percentage (3%-13%) of pregnancies, virus could be found in some fetuses eight days after maternal infection. Despite the low rate of fetal infection, many pups born to dams infected one to eight days before delivery were either stillborn (4%-41%) or died from infection shortly after birth (14%-68%). The actual percentages depended on the time interval from infection of the dams to delivery. Maternal IgG antibody to CB3, which appeared at six to eight days after infection, protected against postnatal mortality, but did not protect against stillbirth.