LABORATORY DIAGNOSIS OF INTRAUTERINE AND PERINATAL VIRUS-INFECTIONS

Background: Intrauterine infection with rubella, cytomegalovirus (CMV) , varicella tester virus (VZV), parvovirus B19 and human immunodeficie ncy virus type 1 (HIV-I) may occur following maternal infection. Diagn osis of congenital infection in the neonate is dependant on the approp riate laboratory techniques being used. Prenatal diagnosis of intraute rine infection may also be indicated. Herpes simplex virus (HSV), HIV- 1, VZV, enteroviruses, hepatitis B (HBV) and hepatitis C viruses (HCV) , human T-cell lymphotropic viruses (HTLV-1 and 2) and genital papillo maviruses (PVs) may be acquired at delivery. Neonatal HSV, VZV and ent erovirus infections may be severe or even fatal. Perinatally acquired HBV, HCV, HIV-I and HTLVs are associated with persistent infection and chronic disease in later life. However, if the mother is identified a s a carrier in the antenatal period, mother-infant transmission of HBV may be prevented by active/passive immunisation of the neonate, HIV-I by caesarian section or antiviral therapy, and of HTLV-1 by avoiding breast feeding. Objectives and study design: To review the techniques available for the diagnosis of intrauterine infections, neonatal infec tions with HSV, HIV-1, VZV and enteroviruses, maternal infection with HBV, HCV and HIV-I and prenatal diagnosis of intrauterine rubella, CMV and B19. Results: Congenital rubella may be diagnosed by detection of specific IgM, but virus detection is the technique of choice for cong enital cytomegalovirus. Congenital VZV may be diagnosed by serological techniques in up to 71%, of cases. Detection of virus in vesicle scra pings or swabs from the oropharynx is the technique of choice for neon atal HSV, while enterovirus infections are best diagnosed by detection of viral RNA. A clinical diagnosis of congenital VZV is often possibl e. HIV-1 may be diagnosed within 3 months of birth by testing serial b lood samples with a combination of techniques. Maternal infection with HBV, HCV, HIV and HTLV1/11 may be diagnosed by serological techniques and genital PVs by detection of viral DNA. Chorionic villus samples, amniotic fluid and fetal blood may be obtained for prenatal diagnosis of infection. Although detection of virus in amniotic fluid is the tec hnique of choice for prenatal diagnosis of CMV, insufficient data is c urrently available to determine whether it may be used for intrauterin e rubella. The most reliable technique for diagnosis of fetal B19 infe ction is detection of viral DNA in fetal blood. Conclusions: Close lia ison between clinicians and microbiologists/virologists is required in order that appropriate specimens are collected from infant and/or mot her and appropriate tests conducted. The use of TORCH screening should be discouraged.