Infections with Cytomegalovirus (CMV). a member of the herpesvirus family, are common in man and are usually mild and asymptomatic. However in pregnant women,' newborns," and immunocompromised
individuals. CMV infections may pose a significant medical risk. CMV infection remains difficult to diagnose on symptoms alone since a high percentage of infections remain without symptoms. In utero infection may result in sequelae of varying degree including mental retardation. chorioretinitis. hearing loss and neurological
problems. Since the risk of in utero virus transmission and CMV related damage of the fetus is strongly increased during primary infection, reliable recognition of primary CMV infections is of high importance for pregnant women. Reinfection with exogenous virus or reactivation of latent virus may lead to the presence of anti-CMV IgM in absence of a primary CMV infection. Although presence of anti-CMV IgG reduces the likelihood of CMV related complications, it does not assure complete protection from disease.
CMV acquisition in infants can occur transplacentally following maternal infection, during birth by contact with the virus excreted from the cervixB or following birth through the ingestion of Infected maternal breast milk. Both seronegative individuals and infants may acquire CMV through infected blood products'' or contact with an infected individual. Children beyond the neonatal period are susceptible to infection and subsequent transmission of CMV when in day care.
If primary infection needs to be excluded, CMV IgG reactive samples should be tested for CMV IgM and CMV IgG Avidity. A positive CMV IgM result in connection with low avidity result is a strong indicator of a primary CMV infection Within the last 4 months.
Manufacturer’s Reagent package insert, Architect CMV IgM, March 2015, Abbott Ireland Diagnostics Division, Finisklin Business Park, Sligo, Ireland.