[Parvovirus B19 infection--dangerous for the fetus]

Human parvovirus B19 infection is a common and usually benign disease in children, but may cause severe complications in pregnancy. We determined the proportion of the pregnant population at risk of infection and present a recent cluster of cases with fetal complications, hoping to raise the general awareness.

Five cases of fetal parvovirus B19 infection during 2001--2 illustrate the delay in diagnosis, treatment and outcome. During the same period, the number of positive and negative serological tests was noted for the catchment area and the entire country. Additionally, 206 consecutive pregnant women were tested to determine susceptibility.

Out of the five cases of fetal complications, all had cardiac involvement, three had anaemia, and two fetuses died. Lag-time to fetal diagnosis was six, eight, and 13 weeks for those with known maternal disease. In Norway, seroconversion is similar to that found in other Nordic countries; 36 % (74/206) of the pregnant population is seronegative. In Norway, parvovirus B19 infection is more frequently reported in the January-June period. A third of the pregnant population is susceptible to infection. Early testing in cases of exposure or suspected infection in pregnancy is recommended in order to ensure appropriate follow-up and treatment.