May 5, 2009
OIE finds human-to-pig H1N1 infection unsurprising
The first known case of human-to-pig infection of the new H1N1 virus is unsurprising because the virus contains avian, human and swine elements, according to the head of the World Organisation for Animal Health (OIE).
But the outbreak of H1N1 at a Canadian pig farm is a non-severe infection followed by recovery, which shows that the virus is not very pathogenic for pigs, and the infection does not boost the chances of the pathogen mutating or becoming more virulent, said Bernard Vallat, Director General of OIE.
More than 200 pigs in the mid-sized pig farm were found having the symptoms of the flu after a farm worker who recently returned from Mexico infected the herd with the virus.
Canada's outbreak is the first confirmed occurrence among pigs.
None of the pigs died but the infected specimens were to be slaughtered "as a precaution", even though the measure was probably unnecessary as there is no evidence that the virus can be transmitted from pigs to humans, Vallat said.
Vallat added that the potential for human infection could not be tested in a laboratory either.
At least 20 countries worldwide have imposed partial or total bans on imported pork, while Egypt has gone even further by ordering the death of all pigs within its borders.
These measures were totally unjustified and there was no evidence of the virus being transmitted through eating pork, Vallat said.
The new virus, first detected in Mexico, has remained relative benign so far but health officials remain on high alert as the pathogen could become more deadly, as happened during three major pandemics in the 20th century, notably the World War 1-era Spanish flu that killed more than 40 million people.
The worry is that one animal could host several viruses at a time, giving them a chance to exchange genes, which is what happened with the current H1N1 virus that contains genetic components from birds, pigs and humans, said Vallat.
The mixture took place in a living animal, but it is unknown which animal it is, Vallat said.
The World Health Organisation raised its pandemic alert to five on a scale of six last week, and could push it up to the highest level if the virus continues to spread.
