Australia: Swine Herd Quarantined

 

# 3566

 

 

A bit of a confusing report out of Australia this morning regarding a pig farm that has been placed under quarantine after swine were found to be infected with an A/H1 influenza.

 

The article states that "It's influenza A, not the human swine flu virus 2009”,  but it isn’t entirely clear from the remainder of the article that the novel H1N1 has been ruled out as a cause.  

 

Further tests, they say, are pending.

 

The concern here is that pigs are notoriously good hosts for influenza; the are susceptible to human flu, bird flu, and of course, swine flu. 

 

When a pig is exposed to two different influenza viruses (such as the novel H1N1 and say . . . seasonal H3N2), it can become simultaneously infected with both strains.   

 

Very rarely when that happens both viruses can infect the same cell and – as the graphic below shows – end up swapping gene segments. This is called reassortment, and it is one of the ways new flu viruses come into being.

 

 

If this new reassorted virus is biologically fit (replicates well and is easily transmissible), it can then spread through the herd and sometimes even jump species back to humans.   

 

The novel H1N1 virus we are dealing with now most certainly evolved through a series of reassortments over the years, until it had obtained the right characteristics it needed to spark a pandemic.

 

Which is why there is so much concern over monitoring, and sometimes quarantining, pig herds. 

 

 

Western NSW piggery quarantined

Friday July 31, 2009, 8:24 pm

 

A piggery in central western NSW has been placed under quarantine after testing found it had been infected with a swine flu, most likely introduced by its own staff.

 

Authorities have stepped in to reassure consumers, saying pork products were still safe to eat.

 

The piggery was placed in quarantine after two tests returned positive for the influenza A H1 virus (A H1 virus), after samples were taken from some pigs on Thursday.

 

Authorities were treating it very seriously, a Department of Primary Industries spokesman said.

 

"It's influenza A, not the human swine flu virus 2009, but further testing is being conducted with the results expected next week," he said.

 

The owner and staff at the piggery had previously suffered flu-like symptoms, and are now themselves being tested for human swine flu.

 

It is the first time pigs had been infected with the A H1 virus in Australia, and follows an outbreak of swine flu H1N1 virus at a Canadian piggery in May.

 

"This is the first case of Influenza A H1 in pigs in Australia and at this stage we believe it was likely introduced by people working with the animals," NSW Primary Industry Minister Ian Macdonald said in a statement.

 

The affected 280-sow piggery which is currently housing about 2,000 pigs has been placed in quarantine and strict biosecurity measures are in place to ensure the virus does not spread."

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