Congenital rubella in south India: diagnosis using saliva from infants with cataract.

Abstract

Congenital rubella is a preventable disease which has largely been controlled through immunization in the developed world. Serological surveys in India, however, indicate that up to 45% of women of childbearing age are susceptible to rubella and potentially at risk of infection during pregnancy. The authors tested saliva and blood serum samples from 95 consecutive infants of mean age 6.2 months with congenital cataract presenting to the pediatric department of the Aravind Eye Hospital in 1993-94 to determine whether the detection of rubella specific IgM from saliva is as reliable as from serum for diagnosing rubella infection and whether rubella is an important cause of congenital cataract in south India. 36 children of mean age 7.3 months attending the same clinic over the same period with a diagnosis of watering eyes served as controls. Serum samples were taken from 61 children with cataract, while saliva samples rich in crevicular fluid were collected from all 131 children using the Orasure device. These samples were then tested for the presence of rubella specific IgM by antibody capture. Rubella specific IgM was detected in saliva and serum in 17 paired samples and was absent in 44 paired samples. Saliva testing gave no false positive and no false negative results compared with serum. 25 of the 95 cases had congenital rubella infection confirmed by detection of rubella specific IgM in saliva. However, congenital rubella was suspected clinically in only 19 of the 25 cases. No control had raised rubella specific IgM.