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The prevalence of enteric adenoviruses detected by an in-house enzyme-linked immunosorbent assay (the RIVM-ELISA) ranged from 13 to 38%, and subgroup F adenoviruses comprised 86%. All subgroup F adenoviruses reacted with both RIVM anti-adenovirus type 40 (Ad40) and anti-adenovirus type 41 (Ad41) monoclonal antibodies but were not detected by Adenoclone Type 40/41 enzyme immunoassay (EIA). The correlation between the Biotrin EIA and RIVM-ELISA results was low (26%). Immunospecific tests suggest that a significant proportion of enteric adenoviruses, possibly comprising previously unidentified or emerging types, are not detected by commercial diagnostic tests in South Africa.

Objective: To analyse adenovirus (Ad) numbers and types associated with paediatric gastro-enteritis in South Africa., Setting: Gauteng, 1994-1996., Methods: A total of 234 paediatric diarrhoeal stool samples were screened for Ad using commercial enzyme-linked immunosorbent assays (ELISAs). Adenoviral isolates were typed, where possible, using restriction enzyme analysis., Results: Ad was detected in 23 (9.8%) specimens, of which 8 (34.8%) were found by subgroup F-specific ELISA to contain Ad40 or 41. Six of these isolates were typed and 2 could not be typed. Of the remaining 15 specimens, 2 isolates had restriction profiles that did not correspond with known Ads, while 2 were identified as Ad31 and 1 as a subgroup C Ad. The remaining 10 specimens negative for Ad40/41 were non-cultivable and could not be typed., Conclusions: The high percentage of non-cultivable Ads other than Ad40/41 is unusual, and may possibly indicate the prevalence of hexon variants of Ad40/41 or of emerging Ad types in South Africa.

Rotaviruses were detected in 32.8% (71/216) of stool specimens collected from young children with gastro-enteritis attending the Rehydration Unit at Umtata General Hospital between April 1988 and March 1989. A seasonal distribution was observed with an increase in numbers shedding the virus during the colder months of the year. Based on variations in the migration pattern of the RNA genome segments when passed through polyacrylamide gels, 14 different electrophoretypes were identified: 69% were long patterns and 27% were short patterns. A single dominant long electrophoretype persisted throughout the 12-month study period, whereas 13 other minor types co-circulated at varying intervals. Mixed infections were observed in three cases, including one infant who was infected with both a long (Wa-like) virus and a short (DS-1-like) virus.

Between March 1983 and December 1986, a total of 1571 stool specimens were collected from black South African infants and young children with acute gastroenteritis, and tested for the presence of rotavirus. Monoclonal antibodies against the major inner capsid protein were used in an enzyme linked immunosorbent assay to determine the subgroup specificity of the rotavirus isolates. Subgroup II rotaviruses occurred more frequently than subgroup I isolates (74.4% vs 12.3%), while 13.3% could not be typed and may indicate the presence of a third subgroup. Two of the subgroup I isolates had a long RNA profile (ie, faster moving gene segment 11) typical of the subgroup II human rotaviruses, and a single subgroup II strain had a short RNA profile possibly indicating an in vivo rotavirus reassortant.

From March 1983 to February 1985, rectal swabs were collected from the black infants admitted to the gastroenteritis unit at Ga-Rankuwa Hospital, Pretoria, Republic of South Africa, to investigate the prevalence of rotavirus-associated gastroenteritis. Overall, 23.1% of the patients tested were found to be positive for rotaviral illness; a definite seasonal pattern emerged, showing a marked increase in the number positive during the autumn. Other factors of importance in terms of rotaviral illness included the age distribution of the patients, the presence of vomiting, and duration of illness.

During a prospective 3-year study, clinical and epidemiological features of rotavirus gastroenteritis in black infants were investigated. Fever and temperatures exceeding 39 degrees C were more frequent in children shedding subgroup II rotaviruses, whereas vomiting was more pronounced in children with subgroup I infection. Diarrhea, dehydration, duration of illness, and the need for admission to a hospital ward were similar in both groups.

The molecular epidemiology of rotavirus infections in black infants in Ga-Rankuwa, South Africa, was investigated by polyacrylamide gel electrophoresis. Between 1983 and 1986, 14 different RNA electrophoretic patterns were observed for children with acute gastroenteritis. These electrophoretypes showed a sequential pattern of appearance, with a limited number being present at any one time. In contrast, for neonates only one RNA electrophoretype was detected, which persisted for at least 3 years.

A prospective 3-year study for enteric pathogens associated with diarrhoea in children was undertaken at Ga-Rankuwa Hospital, South Africa. Rotavirus was the most commonly isolated pathogen (24%), showing a marked seasonal distribution, with an autumn peak in activity. Enterotoxigenic and enteropathogenic Escherichia coli were frequently identified, and Salmonella, Shigella and Campylobacter were also isolated. Cryptosporidium and Giardia lamblia were the most frequently seen parasites. Rotavirus, E. coli, Salmonella and Campylobacter occurred predominantly in children less than 1 year old, whilst Shigella and the parasites were prevalent at all ages.

During 1982 a pilot study was initiated to investigate the prevalence of rotavirus-associated gastro-enteritis among the infants and young children admitted to the Gastro-enteritis Unit at Ga-Rankuwa Hospital. The seasonal parameters of the area were included in the study. From March to December 1982 rectal swabs were randomly collected from 256 of the more than 3 000 admissions to the unit. The swabs were stored at -20 degrees C until assayed in duplicate by an enzyme-linked immunosorbent assay. Overall 32.8% of the patients tested were found to have a rotavirus-associated illness with a definite seasonal pattern emerging, which is not in accordance with other data published for the black population in the RSA.