Rotavirus studies in Indian (Asian) South African infants with acute gastro-enteritis: I. Microbiological and epidemiological aspects.

This study, which is the first one documenting rotavirus (RV) diarrhoea in Asian infants in South Africa, describes the virological and epidemiological aspects of this disease in this population. Fifty-five per cent of 1142 hospitalized cases investigated over a 31-month period showed a positive stool ELISA for RV. Most of these children stopped shedding RV by days 4-6 of hospital admission, though prolonged excretion was recorded in some acute cases for up to 13 days. Mixed RV-bacterial infections occurred in 7% of the total gastro-enteritis (GE) patients, while 8.6% had pure bacterial gastro-enteritis. Sixteen per cent of 188 GE patients had serum anti-RV complement-fixing (CF) antibodies on admission. Rotavirus diarrhoea occurred in half of the seropositive infants. Seroconversion occurred in only two-thirds of the initially seronegative children who had RV diarrhoea. In 5.6% of the RV diarrhoea patients the infection was acquired nosocomially whilst in the hospital for other illnesses. The age-groups mainly affected were between 3 and 14 months, with a peak at 9-11 months; 3% of the RVGE patients were neonates. Both the RVGE and the total GE admissions showed well-marked winter peaks, with an inverse relationship between RV prevalence and both temperature and humidity. It is concluded that RV is the most important cause of infantile GE in this population, whereas pure bacterial infections play a relatively minor role. Circulating anti-RV antibodies do not necessarily afford protection against RV diarrhoea, probably owing to serotypic differences.