Epidemiological study of infantile rotavirus diarrhoea in Tananarive (Madagascar).

An epidemiological study of rotavirus infections was conducted in Tananrive, Madagascar, from November 1988 to October 1990. Rotavirus antigen was detected by ELISA in faecal specimens of 183 of 1,659 children with acute diarrhoea (11%) and in 11 of 631 specimens from children without diarrhoea (1.7%). Rotaviral diarrhoeas were most frequently found in infants aged 6 to 18 months and occurred throughout the year with a definite peak during the first winter months. Analysis of the viral RNA by polyacrylamide gel electrophoresis permitted the characterisation of 170 and 194 strains identified. Nine different electropherotypes (A-I) and one mixed infection were observed. The "short" electropherotypes (A-E) were predominant and represented 140 strains (82.4%), and the "long" electropherotypes (F-I and M) represented 30 strains (17.6%). The "short" electropherotype A (cafb) was the most frequent in our environment (45.3% of cases) and was predominant during the first 14 months of the study. The "long" electropherotype F (bbea) appeared in July 1990 and was predominant during the last three months. Among these children with diarrhoea, the presence of rotavirus was significantly associated with vomiting, fever, and moderate to severe dehydration. However, no significant differences in the occurrence of these symptoms were found between the "short" and "long" electropherotypes.