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

Abstract

In our study, 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%) were found to be IgG-positive and IgM-negative (IgG+gM ), 42 (14%) had neither IgG nor IgM antibodies (IgG /IgM ) and 5 (1.7%) 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 up till the time of delivery, venous blood sample being taken monthly from each one; 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 that who seroconverted) were IgG+IgM , no B19 DNA could be detected in their sera and no adverse effects were documented either by ultrasonographic examination or the detection of maternal serum alpha-fetoprotein. While 5 of these mothers delivered normal children at term, one gave birth to a premature (low-weight) baby who developed severe anemia and had convulsions; this mother was found to have toxoplasma-specific IgM. As based on serial testing of sera, it is notable that B19 IgM may last up to six months. Our data indicates a low incidence rate of B19 infection in pregnancy in our region, at least during interepidemic periods. In addition, it suggests that recent B19 infection represents a low risk for the development of adverse fetal outcomes.