October 3, 2003



New Zealand Investigations On Pig Virus


An exotic animal disease investigation is underway in a New Zealand piggery after weaner pigs failed to respond to veterinary treatment.


Allen Bryce, National Manager Surveillance and Response with New Zealand's Ministry of Agriculture and Forestry (MAF), says the cause of the illness has not yet been confirmed but post-weaning multisystemic wasting syndrome (PMWS) is a possibility. PMWS has not been found in New Zealand before.

"This is a complex disease and confirming the diagnosis is difficult - it may be sometime before MAF can say conclusively whether PMWS is involved or not. While the investigation progresses a restricted place notice has been put on the affected farm," he says.

There are currently no public health or food safety issues associated with this disease, which mainly occurs in weaner pigs aged 6 to 12 weeks. Although the cause of the disease remains uncertain, research has shown that it is associated with porcine circovirus type 2(PCV2), and the clinical signs can be associated with at least two other pig viruses


While the virus is a cause for concern in the NZ pig industry, the country does not expect the presence of such a virus to harm exports in swine. "We are working closely with national and international experts to confirm the diagnosis and the NZ Pork Industry Board has been consulted throughout the investigation," he says.
The disease is characterised by a progressive loss of weight and appetite, pigs have visibly enlarged lymph nodes, and they may experience respiratory distress, diarrhoea, gastric ulcers and jaundice. Generally, infected pigs have a high chance of dying from the disease of which there is no known treatment. Overseas experience shows that the disease might spread between pig herds through the movement of pigs, and possibly in semen.

Mr Bryce says the affected piggery is isolated from other piggeries and doesn't pose a risk while the investigation is underway. Management and control options are being explored as part of the investigation.

PMWS is exotic in Australia and New Zealand but widespread throughout the world.