Scientists to Inquiry Mexican Towns Flu Mystery
Scientists are returning next week to La Gloria, a pig-farming village in the Veracruz mountains where Mexicos earliest confirmed case of swine flu was identified. They hope to learn where the epidemic began by taking fresh blood samples from villagers and pigs, and looking for antibodies that could suggest exposure to previous swine flu infections.
Some experts say its pointless to worry about what happened in La Gloria now that the swine flu virus has spread around the world. But others argue that a thorough investigation could be key to preventing future epidemics.
And Mexico has another reason to care: If it can somehow rule out the possibility that La Glorias pigs infected humans, then it can tell the world it wasnt to blame for the epidemic – that the never-before-seen H1N1 swine flu virus came from somewhere else.
More than half of La Glorias 3,000 residents fell ill with flu symptoms weeks before the new virus was identified. Many found it hard to breathe, burned with fever and ached all over. About 450 of the sickest residents were diagnosed with acute respiratory infections and sent home with antibiotics and masks.
Mexican health officials initially downplayed the outbreak, saying the villagers suffered from regular flu. A 5-year-old boy was the only confirmed swine flu case among 43 villagers whose mucous samples were taken in early April. By then, most other villagers had recovered, and the virus was gone from their systems.
But some disease experts suspect swine flu was circulating more widely in La Gloria.
“I cannot understand it. I could almost bet that there were more infections related to this virus” in La Gloria, Dr. Carlos Arias told The Associated Press. Arias is leading a group of flu detectives from the Biotechnology Institute and the veterinary school of the National Autonomous University of Mexico back to the village at the invitation of the Veracruz state government.
Pigs – like people – get the flu, usually over the winter months. This new swine flu virus is unusual in that it also has infected humans and at this point has become a full-blown human flu.
La Glorias villagers believe they were sickened by the surrounding commercial pig farms, which they accuse of polluting their air and water with pig waste. But the pork industry wants a closer look at pigs raised in the villagers backyards, which may not have been vaccinated or cared for with swine flu-prevention in mind.
Arias said his team also will examine environmental and sanitary conditions in homes where pigs are raised, and make recommendations to the Veracruz government aimed at reducing the potential for human infections.
“It would be very interesting to look at the evolution of this virus and where or how easily the virus originates, reassorts and reassociates genes in an environment like La Gloria,” he said. “But also maybe that would mean that we would have to change the conditions of farming animals.”
Virginia-based Smithfield Foods, Inc., which jointly owns 72 farms in the surrounding La Gloria, said it carefully vaccinates its herd, and has found no signs or symptoms of any kind of swine flu in its herd or its employees anywhere in Mexico.
But those samples were taken weeks after most villagers had recovered from their infections – perhaps too late for the virus to show up. Even after a person or pig recovers, however, antibodies remain in their blood, evidence of the bodys immune response to the infection. And if swine flu antibodies are teased out of pigs in La Gloria, it would suggest, though not definitely prove, that the virus jumped from swine to humans there, Arias said.
Other scientists believe the new strain could have been circulating in humans long before it reached La Gloria. The new strains ancestry has ties to a pig farm in North Carolina where in 1998, scientists discovered that pig, bird and human viruses had combined in pigs to form a new strain of swine flu that also infected a handful of humans.
Most of the current strain can be traced to that combination, about 10,000 generations of the virus ago. At some point along the way, it combined with other flu strains and jumped back into humans – just when and where exactly may never be known, CDC officials have said.
A federal government research team also plans to return to La Gloria, to review health records, interview residents and search for antibodies. The boys positive test result “has to lead us to go back and look closer,” said Dr. Ethel Palacios, deputy director of Mexicos swine flu monitoring effort.
Labs capable of testing for the new swine flu strain have focused on helping sick people rather than find scientific evidence pointing to the starting point of the epidemic, which has now sickened more than 10,000 people around the world and killed 80, mostly in Mexico.