Neonatal cytomegalovirus infection: diagnostic modalities available for early disease detection.

CMV is a ubiquitous virus. In India, there is high seroendemicity with almost 99% adults showing IgG antibodies. Infection or re-activation becomes important in immunocompromised host (Transplant recipients, Cancer therapy patients and patients with HIV/AIDS). Neonates form a distinctive high risk population for congenital CMV infection and suffer disastrous sequlae of the same. Neonatal infections may be congenital in nature or may be acquired after birth during first month of life via infected breast milk or due to exposure to high risk blood products. The risk for transmission of the virus to the fetus is higher in primary infected mothers than in mothers with reactivated disease. Primary CMV infections are reported in 1-4% of seronegative women during pregnancy and the risk for viral transmission to fetus is 30-40%. Reactivation of a CMV infection during pregnancy is reported in 10-30% of seropositive women and the risk of transmitting the virus is about 1-3%. The adverse outcome of congenital neonatal CMV infection includes-microcephaly (70%), intellectual impairment (60%), sensineural hearing loss (35%), choriorenitis (22%), hepatosplenomegaly (70%), jaundice (68%), thrombocytopenia (65%), low birth weight (65%), pneumonitis (2-5%) and congenital heart disease (<5%). About 5-10% of congenitally infected asymptomatic infants will have neurological problems later in life the most common of which is unilateral or bilateral sensory neural hearing loss. All immunocompromised hosts, including pre-term neonates, mount weak antibody responses (IgM), making serological detection of CMV infection in them, fallacious. Thus, it is imperative to use antigen detection methods such as quantitative PCR or PP65 Antigenaemia assays to detect CMV infection in immunocompromised host. Sakhuja et al and Minz et al have demonstrated that PP65 Antigenaemia assay is very good for diagnosing CMV disease in renal transplant recipients. The present review tends to highlight the role of newer diagnostic modalities in early CMV infection detection in neonatal population.