Pigs Hold Clues to Man-Made Flu

Samples taken from South Korean pigs contain genes from a human flu virus created by scientists in 1933, and one American flu researcher says the sequences could represent a dangerous situation for humans.

The World Health Organization, which monitors the worldwide spread of flu, is remaining mum until researchers finish an investigation of the pig samples.

The presence of a man-made human flu virus in pigs may be worrisome for several reasons. First, a man-made virus has no business in pigs -- did the virus get there naturally, or was it a lab accident? More frighteningly, but less likely, was it bioterrorism? Second, viruses often use pigs as a conduit to humans, who would have little or no immune resistance to this particular strain of flu since no one has been exposed to it.

"In terms of flu, pigs have always represented a danger to humans because these animals act as a mixing vessel for various strains of influenza," said Dick Thompson, a spokesman for the World Health Organization.

But WHO won't be convinced that the data is real -- that the human sequences are not a result of laboratory contamination instead of human virus in a pig -- until more laboratories can verify the samples.

Henry Niman, founder of Recombinomics and a researcher who has sleuthed the spread of bird flu and its changing genetic makeup for two years, says the investigation is moving too slowly. If pigs in Korea are carrying a man-made human flu, authorities should take action immediately to prevent it from spreading.

Sang Heui Seo of Chungnam National University in Daejon, South Korea, entered six genetic sequences from pigs into GenBank in late October. Niman came across the data in late November, and noticed they contained between three and seven genes from the WSN33 virus, which was created in 1933 by a London lab that was researching the 1918 flu pandemic. The London lab found that the virus could infect mice, indicating that it might successfully infect humans, Niman said. He reported the presence of the human WSN33 genes in Seo's samples to WHO officials in early December.

According to a news article in Science, WHO initially dismissed the data as lab contamination based on the fact that a researcher at St. Jude's Children's Hospital in Memphis, Tennessee, said he had shipped samples of WSN33 to Seo's lab. But Seo told Science he never received any WSN33.

St. Jude's declined to comment on the Korean pigs, and Seo did not return e-mails requesting comment.

Seo submitted his pig data to Science for publication, but the journal's editors rejected the research, asking for outside lab testing to verify that the data was valid. Labs in Hong Kong and at the University of Wisconsin-Madison are now verifying the samples. WHO is also waiting for the results to decide whether the pigs might be a danger to humans.

"If there really are WSN33 sequences in pigs -- and probably birds -- on farms in Korea," Niman said, "then there is a very major problem."

Niman says the evidence can likely be explained by one of two possibilities: Either the man-made virus escaped from a lab, or the virus' genes are recombining -- morphing in a way that most flu researchers believe is impossible.

"(WHO doesn't) want to think about the fact that it escaped from some lab, which is most certainly what happened, and they certainly don't want to think about recombination," Niman said.