Survey of parvovirus B19 infection in a cohort of pregnant women in Belém, Brazil

ABSTRACT

A total of 300 pregnant women were screened for the presence of human parvovirus B19 IgG and IgM antibodies by an enzyme-linked immunosorbent assay (ELISA). Overall, 253 (84.3 percent) were found to be IgG-positive and IgM-negative (IgG+IgM-), 42 (14 percent) had neither IgG nor IgM antibodies (IgG-/IgM-) and 5 (1.7 percent) were both IgM- and IgG-positive (IgG+/IgM+). Maternal serology was performed routinely for cytomegalovirus, rubella, toxoplasmosis and syphilis. All IgG-/IgM- and IgG+/IgM+ women were followed until the time delivery, with venous blood samples taken monthly from each, one IgG-/IgM- mother seroconverted to IgG+/IgM- and B19 DNA was detected by nested polymerase chain reaction technique (PCR) in her serum. All babies born to IgG+/IgM+ mothers (and from the one who seroconverted) were IgG+IgM-, but no B19 DNA could be detected in their sera and no adverse effects were documented either by ultrasonographic examination or by detection of maternal serum alpha-fetoprotein. While 5 of the mothers delivered normal children at term, one gave birth to a premature (low-weight) baby who developed severe anemia and had convulsions. However, this mother was found to have toxoplasma-specif IgM. Our data indicate a low frequency of B19 infection in pregnancy in our region, at least during interepidemic periods. This appears to be partly due to high prevalence of prior infection among pregnant women. Recent B19 infection in 6 women did not lead to adverse fetal outcomes. This observation, however, in a small number of serologically positive patients, does not contradict the observations by others that recent infection does converg a risk for the fetus.