An outbreak of gastroenteritis caused by both rotavirus andShigella sonneiin a private school in Rio de Janeiro

Abstract

SummaryIn May 1980 an extensive outbreak of gastroenteritis occurred in a private school in the city of Rio de Janeiro. Examination of faeces and paired sera showed that this outbreak was caused by both rotavirus and a virulent strain ofShigella sonnei. In the first 19 stool samples collected seven (37%) had rotavirus only, six (32%) hadSh. sonneionly, while four (21 %) had both agents. Examination of the second and third stool collections revealed only the presence ofSh. sonnei. The 18 paired sera showed seroconversion for rotavirus in four cases (22%) and in seven cases (39 %) forSh. sonnei. The overall attack rate of the disease was approximately 75 %, the nursery and kindergarten having higher attack rates. Students in all grades became sick at the same time, and the unimodal curve of the onset dates of symptoms indicates a common source outbreak. Evidence suggested a contaminated water supply.