Swine flu source spawns wild theories

LONDON (Reuters) - Dead pigs in China, evil factory farms in Mexico and an Al Qaeda plot involving Mexican drug cartels are a few wild theories seeking to explain a deadly swine flu outbreak that has killed up to 176 people.

Nobody knows for sure but scientists say the origins are in fact far less sinister and are likely explained by the ability of viruses to mutate and jump from species to species as animals and people increasingly live closer to each other.

“The pig has been considered the mixing bowl of influenza viruses. Both avian flu and pig flu viruses have spread via the pig to humans,” Paul Yeo, a virologist at Durham University in Britain, said on Thursday.

“The problem now with this virus is that it has picked up a mixture of elements, now including human elements. It’s a complex virus.”

Twelve countries have confirmed cases of the H1N1 strain, a new infection that has brought the world to the brink of a pandemic.

Related Coverage

Finding the source of a new virus is key for scientists because understanding how it jumped to humans can lead to better drugs and vaccines as well as help prevent future outbreaks.

But one link experts probably won’t be exploring is an Internet report charging that Mexican drug cartels working with al Qaeda unleashed the swine flu.

“The claim of the conspiracy theorists is that this new combination could not have occurred naturally, but this is not true,” the New Scientist’s biology editor Michael Le Page wrote.

“Flu viruses consisting of a mixture of human, swine and bird strains have been found before.”

Sound science, however, is no match for the Internet and unsubstantiated media reports when it comes to providing a forum for ideas that have forced responses from governments and companies alike.

China’s Ministry of Agriculture, for example, on Wednesday denied overseas reports charging that dead pigs found in a south eastern province might be to blame for swine flu, according to an official Xinhua news agency article.

And in Mexico reports in at least two newspapers focused on a factory farm run by a subsidiary of global food giant Smithfield Foods. Some of the rumors mentioned noxious fumes from pig manure and flies -- neither a known vector for flu viruses.

Those reports brought a swift reply from the biggest U.S. hog producer.

“Based on available recent information, Smithfield has no reason to believe that the virus is in any way connected to its operations in Mexico,” the company said in a statement.

Viruses spread much more easily on factory farms where animals are packed together than in the wild but so far there is no evidence that any one particular farm is the source.

Reporting by Michael Kahn; Editing by Maggie Fox and Richard Hubbard