Group A is probably the common pig one, but B, C and E also occur. However the frequency with which different ones occur is unknown and from a practical view point it is probably academic.

Rotaviruses are ubiquitous and they are present in most if not all pig herds with virtually a 100% sero-conversion in adult stock. A further epidemiological feature is their persistence outside the pig, where they are resistant to environmental changes and many disinfectants. Maternal antibodies persist for 3-6 weeks after which pigs become susceptible to infection but exposure does not necessarily result in disease. It is estimated that only 10-15% of diarrhoeas in pigs are initiated by a primary rotavirus infection.

The fact that the virus persists in the environment accounts for widespread infection and therefore a constant risk of disease.

Clinical signs

In a mature herd disease appears after piglets are 7 to 10 days of age, with a watery profuse diarrhoea in younger animals and a progressively less important with age. However if pathogenic strains of E. coli are present severe disease can occur with heavy mortality. Villus atrophy is a consistent feature with dehydration and malabsorption and diarrhoea usually persists for 3-4 days. Pigs look hollow in the abdomen the eyes are sunken and the skin around the rectum is wet.

The role of rotaviruses in the post-weaned pig is probably less important although they are often identified when acute E. coli diarrhoea occurs in the first 7-10 days after weaning.

Diagnosis

Whenever there is a diarrhoea problem in pigs from 10 to 40 days of age rotavirus infection either as primary agents or secondary must be considered. Laboratory examinations are required by electron microscopy and ELISA tests. Try the litmus test by soaking scour in litmus paper, E. coli infections turn blue, virus infections red.

Treatment

• There are no specific treatments for rotavirus infections.
• Provide antibiotic therapy either by injection, by mouth or in the drinking water, to control secondary infections such as E. coli.
• Apralan, amoxycillin, neomycin, framycetin and enrofloxacin could be used.
• Provide dextrose/glycine electrolytes to counteract dehydration.
• Provide dry warm and comfortable lying areas.