Murine experimental infection with rotavirus SA-11: clinical and immunohistological characteristics.

Six- to eight-day old (lactent) mice were inoculated orally with simian SA-11 rotavirus. During the first hours after infection, the virus was already detected in villous apical enterocytes by immunohistologic reaction of paraffin sections of the duodenum and jejunum but not in the ileum. Late on the first day, some animals developed already diarrhoea and pathologic lesions were observed in the duodenum and jejunum. During the second day most mice developed diarrhoea; tissue lesions were intense and maximal from duodenum to ileum when compared to other days and some colon sections had mild pathological characteristics. At this point, the virus in the ileum was only detected by immunohistologic reaction. During the third day some animals still had diarrhoea but tissue histology was regenerated and no virus could be detected. We conclude that the SA-11 model follows an infection pattern similar to Epizootic Diarrhoea of Infant Mice (EDIM) and propose to study immunological parameters as young susceptible animals mature into adult resistant ones.