A molecular epidemiological study of porcine rotaviruses

Diarrhoea in the piglet can lead to stunted growth and neonatal death, with important implications for the pig farmer. During 1993, a pilot study was initiated to monitor the epidemiology of rotavirus infection in piglets with diarrhoea. Bimonthly diarrhoeal faecal specimens were collected from scouring piglets less than 6 weeks of age on a pig farm in the Northern Transvaal. The stool specimens were examined by a commercial enzyme-linked immunosorbent assay (Rotavirus EIA, IDL, Jerusalem). In total, rotavirus antigen was detected in 24% of the litters by the ELISA, which is directed at the group A rotavirus antigen. Rotavirus was found to occur throughout the year and predominantly in piglets 4 weeks old. Polyacrylamide electrophoretic analysis of the viral RNA genomes showed the presence of four distinct strains of Group A rotaviruses circulating on this farm. This study highlights the natural diversity of rotavirus strains circulating on a single farm and may indicate the importance of rotavirus infection in piglets with diarrhoea in South Africa.