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14 October 2003
A provisional diagnosis of Post-weaning multisystemic wasting syndrome (PMWS)
has been made on a Waikato piggery which is under investigation by the Ministry
of Agriculture and Forestry (MAF).
Clifton King, MAF's Programme Coordinator Exotic Disease Response said that
although final results on tissues samples will not be available until the end of
the month, clinical and pathological criteria had been met.
"It has been difficult to get a definite diagnosis as PMWS is a complex
disease associated with two viruses that are already present in New Zealand –
porcine parvovirus (PPV) and porcine circovirus type 2(PCV2).
"Final confirmation of the disease is dependent upon finding PCV2 DNA in
tissues samples sent overseas. However, clinical signs and New Zealand pathology
results suggest that we do have PMWS in this farm," he said.
Mr King said that MAF had requested a second round of tests after results
from tissue samples sent to Seoul National University in Korea in September were
A Technical Advisory Group (TAG) made up of representatives from MAF, pork
industry and national experts has been established to consider further
investigation and control options now that a provisional diagnosis has been
Tracing of pigs and other risk items on and off the affected farm has been
completed. Six farms have been identified that may have come in direct or
indirect contact with this farm. Results from the tracing will be analysed
within the month but there have been no reports of disease found on any of the
identified farms to date. Once this analysis is completed the TAG will meet
again to decide possible next steps.
"Given that PCV2 and PPV are endemic in New Zealand, MAF needs to
consider the possibility that the conditions for PMWS have been present in New
Zealand for some time. In the meantime the restricted place notice will remain
in place while the investigation is underway," he said.
Mr King said that while PMWS is of concern to the pig industry, the impact on
our trade would be negligible, as the viruses are present in virtually every
pork producing country in the world.
MAF became involved in the investigation in early in September after being
contacted by a veterinarian concerned that weaner pigs had failed to thrive even
after veterinary care and farm management advice.
PMWS 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 high morbidity and mortality and no known treatment.
The New Zealand Food Safety Authority confirms that there are no food safety
issues associated with this disease, which is specific to weaner pigs aged six
to 12 weeks.
To report suspected PMWS please call the MAF Exotic Disease and Pest
Emergency Hotline on 0800 809 966.
For further information contact:
Philippa White MAF Communications Adviser 04 498 9948 or 027 223 1875