Viruses that infect pigs are a form of Influenza A and cause regular outbreaks writes DR MUIRIS HOUSTON, Medical Correspondent
THE OUTBREAK of swine flu among a herd of pigs highlights a potential confusion around the original naming of the novel virus which was first identified in humans in April of this year.
Pandemic (H1N1) 2009 – to give the human version its now official WHO definition – is a brand new version of Influenza A.
However, swine flu viruses – those that infect pigs – have been around since 1930. They too are forms of Influenza A and cause regular flu outbreaks among pigs during autumn and winter.
It is a mild respiratory disease in pigs that has occasionally infected humans in the past. These cases occur in people with direct contact with pigs, typically farm workers or children who have petted an infected pig.
The swine flu that originated in Mexico this year – Pandemic (H1N1) 2009 – is a genetic mixture of viruses seen in pigs, birds and people. It was called swine flu because it is structured like a virus that usually infects pigs. But it is now a distinctly recognised human influenza virus that could mutate again.
Researchers now think it was circulating in pigs for about 10 years before it made a mutational jump to people.
The latest flu virus can spread from humans to pigs, as the outbreak in the pig farm in the Republic illustrates. Swine flu can also spread from pigs to humans. But the viruses are quite different in their make up, so that a vaccination for the human H1N1 version is unlikely to protect a person from contracting swine flu from a pig.
What can be said with certainty is that it is impossible for a person to get swine flu from eating pork; it is a respiratory virus that cannot be transmitted by food.