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

PIP: 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.^ieng

Use of PCR for prenatal and postnatal diagnosis of congenital rubella.

A reverse transcription-nested PCR assay (RT-PCR) was evaluated for diagnosis of congenitally acquired rubella in utero and during infancy. RT-PCR was compared with virus isolation for retrospective detection of rubella virus in placental and fetal tissues obtained after termination of pregnancy following primary rubella or rubella virus reinfection. Concordant results were obtained for 85% of samples; rubella virus RNA was detected by RT-PCR alone in four samples, and rubella virus was detected by isolation alone in two samples. Samples were also obtained for prenatal diagnosis of congenital infection; rubella virus RNA was detected in three of seven chorionic villus samples and one of three amniotic fluid samples by RT-PCR, while rubella virus was isolated in only one chorionic villus sample. To demonstrate that the RNA extracted from chorionic villus samples contained amplifiable RNA, a nested RT-PCR was used to detect keratin mRNA. Rubella virus was detected in placenta in two cases in which the fetus was uninfected, and there was no evidence of rubella virus in the placenta from one case in which the fetus was infected. Thus, detection of rubella virus in chorionic villus samples by RT-PCR may not always correctly predict fetal rubella virus infection. RT-PCR was successfully used for the diagnosis of congenitally acquired rubella in infancy. Rubella virus RNA was detected in cyropreserved or formalin-fixed lens aspirates obtained from infants in India with serologically confirmed congenital rubella but not in samples from controls with inherited cataract.

Causes of childhood blindness in Sri Lanka: results from children attending six schools for the blind.

AIM: The survey aimed to identify the major treatable or preventable causes of visual loss in children attending blind schools in Sri Lanka so that appropriate control measures can be implemented. METHOD: A total of 226 children with blindness (BL) or severe visual impairment (SVI) attending six schools for the blind were examined and details recorded using the WHO standard reporting form. RESULTS: Cataract was responsible for 17% of BL/SVI and was the commonest 'avoidable' cause of childhood blindness. Bilateral microphthalmos accounted for one quarter of BL/SVI. Vitamin A deficiency was not a significant cause of visual morbidity. CONCLUSION: The pattern of childhood blindness seen in this study is typical of a growing number of south east Asian countries which are developing rapidly. Childhood cataract is a major avoidable cause that can benefit from future intervention strategies.