This economically important, panzootic disease causes reproductive failure in breeding stock and respiratory tract illness in young pigs. Initially referred to as "mystery swine disease" and "mystery reproductive syndrome", it was first reported in 1987 in North America and Central Europe. The disease costs Europe almost 1.5b€ every year.
Infection in humans is associated with direct exposure to infected pigs or infected raw or undercooked pork products.
A spokesperson from the VMD said:
"This outbreak has been caused by an emergent recombinant strain of PRRS virus which is believed to have resulted from the recombination of vaccine strains from two live PRRS vaccines which had both been used on the farm."
Further investigation into the outbreak is ongoing. Whilst waiting for further information, the European Medicines Agency (EMA) has produced some advice for all users of live PRRS vaccines:
- In order to limit the potential risk of recombination between vaccine strains, the simultaneous or consecutive use of different live attenuated PRRSV vaccines should be avoided as much as possible while continuing to protect animal health.
- Increased monitoring of any suspected adverse event relating to clinical signs of PRRS, including the occurrence of relevant clinical signs of the disease in vaccinated herds, is recommended. Any suspected adverse event should be reported to the national competent authority for veterinary medicines or the marketing authorisation holder. Clinical signs of PRRS include reduced fertility, increased rate of abortions, reduced appetite, increased piglet mortality and respiratory distress.