Experimental infection of chickens with rotaviruses: clinical and virological findings.

Specific-pathogen-free chickens were infected orally with two different isolates (Ch 1 and 132) of chicken rotavirus. Chickens aged 1, 14 and 28 days were equally susceptible to infection. Following infection with either virus, the clinical signs were mild. Coincident with the peak of virus excretion and for a period of 1 to 2 days, infected birds passed increased quantities of caecal droppings. At necropsy, the caeca were abnormally distended with gas and fluid. Immunofluorescence showed that for both viruses the principal site of replication was the mature villous epithelial cell of the small intestine. However, Ch 1 rotavirus grew best in the duodenum while 132 virus favoured the jejunum and ileum. Ch 1 rotavirus and 132 virus were detected by direct electron microscopy in the faeces from 2 to 5 days and 1 to 7 days respectively after infection.