Rubella and cytomegalovirus (CMV) infections: laboratory aspects of investigation of antenatal, congenital, persistent, and subclinical infections.

Rubella specific IgM tests carried out on pregnant women with history of rubella contact or rubella-like rash indicated the presence of rubella-IgM by the second week after contact, persistence to 3-4 weeks followed by a decline and non-detectability around 8-9 weeks and at delivery. Laboratory investigation of cases of rubella infection in infants and children, including clinically proven and suspected congenital rubella revealed distinct patterns of combinations of positivity and negativity of IgM and IgG antibodies. Three cases of persistence of rubella specific IgM antibodies with one even up to 3 years in congenital rubella and a case of CMV-IgM persistence in congenital CMV are described. Rubella-IgM and CMV-IgM were detected in the serum of two patients aged 12 years and 24 years with CMV mononucleosis. Utilization of rubella-IgM/CMV-IgM tests enabled the identification of four cases of subclinical rubella and one of subclinical CMV in a pediatric population.