Laboratory diagnosis of intrauterine and perinatal virus infections.
BACKGROUND
Intrauterine infection with rubella, cytomegalovirus (CMV), varicella zoster virus (VZV), parvovirus B19 and human immunodeficiency virus type 1 (HIV-1) may occur following maternal infection. Diagnosis of congenital infection in the neonate is dependent on the appropriate laboratory techniques being used. Prenatal diagnosis of intrauterine 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 papillomaviruses (PVs) may be acquired at delivery. Neonatal HSV, VZV and enterovirus infections may be severe or even fatal. Perinatally acquired HBV, HCV, HIV-1 and HTLVs are associated with persistent infection and chronic disease in later life. However, if the mother is identified as a carrier in the antenatal period, mother-infant transmission of HBV may be prevented by active/passive immunisation of the neonate, HIV-1 by caesarian section or antiviral therapy, and of HTLV-1 by avoiding breast feeding.


OBJECTIVE
To review the techniques available for the diagnosis of intrauterine infections, neonatal infections with HSV, HIV-1, VZV and enteroviruses, maternal infection with HBV, HCV and HIV-1 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 congenital cytomegalovirus. Congenital VZV may be diagnosed by serological techniques in up to 71% of cases. Detection of virus in vesicle scrapings or swabs from the oropharynx is the technique of choice for neonatal HSV, while enterovirus infections are best diagnosed by detection of viral RNA. A clinical diagnosis of congenital VZV is often possible. HIV-1 may be diagnosed within 3 months of birth by testing serial blood 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 technique of choice for prenatal diagnosis of CMV, insufficient data is currently available to determine whether it may be used for intrauterine rubella. The most reliable technique for diagnosis of fetal B19 infection is detection of viral DNA in fetal blood.


CONCLUSIONS
Close liaison between clinicians and microbiologists/virologists is required in order that appropriate specimens are collected from infant and/or mother and appropriate tests conducted. The use of TORCH screening should be discouraged.
Best
J M
JM
United Medical and Dental Schools of Guy's and St Thomas's Hospitals, St Thomas's Campus, London SE1 7EH, UK.