Parvovirus B-19 infection is a common mild illness in adulthood and usually subclinical in childhood. Serious illness can be caused by this virus in certain circumstances. When a pregnant female contracts parvovirus B-19 complications may affect the fetus and/or the newly born. A study of 240 parturient mothers was carried out to assess the possible role of this virus in abortion. Detection of virus-DNA in fetal tissues by PCR confirmed mother-fetus transmission.
Introduction
Parvovirus B-19 (Pattison and Patou, 1996) is a single strand DNA virus of small size that infects humans usually by inhalation, but can be transmitted by blood, blood products, plasma and bone marrow transfusion (Siegl and Cassinolty, 1988). In immunocompetent persons subclinical infection is predominant. The clinical infection of children is erythema infectiosum and of adults are polyarthritis, transient aplastic crisis, and pure red cell aplasia. Infected adult pregnant females in their first trimester, may transmit parvovirus B19 to their fetus where infection of the fetal heart leads to non- immune hydrops fetalis, and erythrocyte progenitor cell suppression. Parvovirus B19 infects placental endothelia with high titer output that enables the virus to cross the placenta barrier to the fetus where it grows in liver, bone marrow, heart and skin. Multi-organ infection may progress to abortion, still birth or postnatal death (Enders et al. 2004 and Yong et al. 2004). Parvovirus B-19 may cause chronic infection (Frickhofen and Young 1989 and Koch & Adler 1990).
Parvovirus B19 serological and molecular tests are used to diagnose infection. IgM anti-parvo B19 is a marker of early immune
response in acute infection. IgG anti Parvovirus B19 is a marker of past exposure. The enzyme-linked immunosorbent assay (ELISA) test is used to assay these antibodies in patient's sera but not in fetal blood due to the immature immune system response. Detection of Parvovirus B19 ā DNA by polymerase chain reaction (PCR) is used to evaluate qualitatively or quantitatively viral DNA. Viremia titer is up to 1011 to 1013 genome equivalents/ml). There are variations in Parvovirus B19 PCR results, because of the choices of primer sites, the PCR procedure (Anderson et al., 1985) and the existence of virus variants (Heegaard et al., 2001; Servant et al., 2002; Saldanha et al., 2002; Hokynar et al., 2004). In our study we selected Parvovirus B19 VP1 gene primers for PCR according to Koch and Adler (1990).
Aim of Study
To assess mother to fetus transmission of parvovirus B-19 when pregnant mothers are hospitalized for spontaneous abortion in the first trimester.