Embryonic malformations in a case of intrauterine parvovirus B19 infection

An incomplete embryo of 9 weeks development from a woman infected by human parvovirus B19 during early pregnancy was histologically examined. B19-DNA was detected in both embryonic and placental tissue by dot-blot hybridization. Focal vascular endothelial damage was found throughout the entire embryo and placenta together with mononuclear infiltrations around the vessels. In the placenta these mononuclear cells belonged for the greater part to the cytotoxic and/or suppressor T-cell group. One eye showed lens abnormalities and retinal folds. The other eye was microphthalmic and aphakic and showed dysplasia of the sclera, anterior segment, and retina. The skeletal muscle cells displayed a general eosinophilic degeneration. Focally, similar changes were found in heart muscle and smooth muscle tissue. In several tissues pathologic effects at a cellular level were noted, as intranuclear vacuole-like inclusions and nuclear ballooning. On the basis of this study it is concluded that human parvovirus B19 may affect several fetal tissues and may even have teratological effects on a developing human embryo.