An outbreak of group C rotavirus gastroenteritis among adults living in Valentim Gentil, São Paulo State, Brazil

An outbreak of gastroenteritis affecting adults and children occurred in the small city of Valentim Gentil, São Paulo, Brazil, in 1993. Nineteen faecal samples (from 10 cases and 9 contracts) were examined by direct electron microscopy (DEM), immune electron microscopy (IEM), polyacrylamide gel electrophoresis (PAGE), and enzyme-linked immunosorbent assay (ELISA) for group A and C rotaviruses. DEM detected rotavirus in 6 of the 10 cases and in none of the contacts. All of the samples were negative for group A rotavirus by ELISA. Analysis by PAGE showed an electrophoretic profile suggestive of group C rotavirus in two cases. Group C rotavirus was identified by IEM in 4 of the cases and in 1 of the contacts. All of the samples were submitted to ELISA for group C rotavirus. This resulted in a total of 10 positives-7 for diarrhoeal cases and 3 for contacts. This outbreak was strongly associated with group C rotavirus. The importance of combining different diagnostic methods is emphasised.

A novel human rotavirus serotype with dual G5-G11 specificity

Rotavirus serotype G5 isolates were recently recovered from children with diarrhoea in Brazil. Like most human strains, they exhibited long electropherotypes and subgroup II and Wa-like VP4 specificity. We report the successful propagation and the molecular and antigenic characterization of one of these isolates (IAL-28). Cross-neutralization of IAL-28 and a single gene reassortant, UK x IAL-28, which contains the gene encoding the IAL-28 VP7 in the UK genomic background, with prototype G1 to G14 rotaviruses demonstrated that IAL-28 has antigenic determinants specific for both G5 and G11 serotypes. Sequence analysis of the gene encoding VP7 suggested that one or two amino acid substitutions at positions 96 and 100 on IAL-28 VP7 were possibly responsible for the additional G11 specificity. G5 rotaviruses are found in horses and predominate in piglets, whereas G11 has been identified exclusively as a swine pathogen.

Outbreak of severe gastroenteritis in adults and children associated with type G2 rotavirus. Study Group on Diarrhea of the Instituto Adolfo Lutz

An outbreak of severe gastroenteritis affecting 132 adults and children occurred in the small city of Mirassol, São Paulo, Brazil, in 1992. The outbreak of diarrhoeal disease had an abrupt onset and afflicted all age segments of the population. Group A rotavirus was the only pathogen associated with the epidemic. It was detected in 12 of the 27 (44%) stool specimens analyzed and was identified as serotype G2 rotavirus. Severe dehydration was common among adults and older children, and 35% of all the notified cases were hospitalized for parenteral rehydration. Contamination of the main water supply was the most likely source.

Immunological factors in milk from Brazilian mothers delivering small-for-date term neonates

Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n = 16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight (n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages.