Infection with the virus causes encephalomyocarditis and reproductive disease in pigs.

The disease can be found worldwide but is of greatest economic importance in tropical areas.

Piglets that are infected present with encephalitis, myocarditis and sudden death.

If a sow is infected whilst pregnant she may present with a variety of reproductive signs including infertility, mummification, abortion, still birth and the birth of weak piglets.

A presumptive diagnosis can be made based on the history and clinical signs.