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2 October 2003
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 the 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 no public health or food safety issues associated with this
disease which is specific to weaner pigs aged 6 to 12 weeks. While certainly its
presence is of concern to the pig industry, it will have a negligible impact on
our trade because it is wide spread throughout the world, " he said.
Mr Bryce says the cause of PMWS is still uncertain. Research shows that it is
associated with porcine circovirus type 2(PCV2), and the clinical signs can be
associated with at least two other pig viruses - porcine reproductive and
respiratory syndrome virus (PRRSV) - and porcine parvovirus (PPV). PCV2 and PPV
are present in New Zealand. PRRSV is exotic to New Zealand. Diagnostic tests
have definitely excluded the presence of PRRSV on the affected farm.
"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. It can vary in severity and
virulence but generally there is low morbidity, and high mortality of affected
pigs. There is no known treatment. Overseas experience shows that the disease
might spread between pig herds through the movement of pigs, and possibly in
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 widespread throughout the world; exceptions include Australia and New
For more information contact:
Philippa White, MAF Communications adviser, 027 223 1875 or 04 498 9948