Prevalence of parvovirus B19 antibodies in pregnant women in northern Benin

Abstract

AbstractObjectivesParvovirus B19 (B19V) infection in pregnancy is generally asymptomatic, but in about 3% it can cause complications, including miscarriage, severe foetal anaemia and foetal hydrops. The seroprevalence in pregnancy ranges from 20% to 82% in Africa, but there are no data for Benin. We therefore retrospectively assessed the seroprevalence of B19V in pregnant women attending the Saint Jean de Dieu Hospital in Tanguiéta, a rural district of Atacora, in northern Benin.MethodsWe searched for anti‐B19V immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in 227 sequential sera from as many women (mean age 26.3 years, range: 16–41) of whom 30 were in the first trimester, 66 in the second and 131 in the third. Samples that tested positive for IgM were analysed with an immunoblot test and the viral genome (DNA‐B19V) was searched for using a polymerase chain reaction.ResultsOf the 227 women, 153 (67.4%) were positive for IgG anti‐B19V, 7 (3.1%) for IgM and 73 (32.2%) were non‐immune. Six IgM‐positive women were also IgG positive. The difference in IgG seroprevalence between trimesters or ages was not statistically significant. Of the seven IgM‐positive samples, three were confirmed positive by immunoblot (of which two were DNA‐B19V positive), three were indeterminate (DNA‐B19V negative) and one was negative (DNA‐B19V negative). Of the three women with confirmed positive IgM, two were in the third trimester and one in the second trimester of pregnancy.ConclusionsThe seroprevalence of anti‐B19V IgG among pregnant women in Benin is high and in line with those reported in some African countries. IgM seroprevalence is also similar to that described in some African countries in non‐epidemic periods. The low viral load observed depicts non‐acute infections, but it is difficult to establish the precise time of the infection, especially for women tested in the second or third trimester of pregnancy, when the observed viremia could be a sign of an acute infection that occurred in the previous trimester. Consequently, clinical follow‐up and further investigations to highlight possible foetal consequences are indicated.