Chile said Friday that tests show swine flu has jumped to birds, opening a new chapter in the global epidemic.
Top flu and animal-health experts with the United Nations in Rome and the U.S. Centers for Disease Control and Prevention in Atlanta were monitoring the situation, but said the infected turkeys have suffered only mild effects, easing concern about a potentially dangerous development.
Chile's turkey meat remains safe to eat, the experts said, and so far there have been no signs of a deadly mutation. None of the birds have died from this flu, according to the farms' owner, Sopraval SA.
Chile's health ministry said it ordered a quarantine Friday for two turkey farms outside the port city of Valparaiso after genetic tests confirmed sick birds were afflicted with the same virus that has caused a pandemic among humans. The infected birds are contained within closed buildings, preventing any spread to wild birds, the farms' owner said.
So far, the virus — a mixture of human, pig and bird genes — has proved to be very contagious but no more deadly than common seasonal flu. However, virus experts fear a more dangerous and easily transmitted strain could emerge if it combines again with avian flu, which is far more deadly but tougher to pass along.
‘No mutation at all’
Sopraval alerted the agriculture ministry after egg production dropped at the farms this month. After initial tests on four samples, further genetic testing confirmed a match with the subtype A/H1N1 2009, the agriculture and health ministries announced.
"What the turkeys have is the human virus — there is no mutation at all," Deputy Health Minister Jeannette Vega told Chile's Radio Cooperativa on Friday.
The Health Ministry said it ordered a complete quarantine Friday and alerted the U.N.'s World Health Organization. The U.N.'s Food and Agriculture Organization, meanwhile was working closely with Chilean government scientists, said Dr. Juan Lubroth, the head of infectious diseases for FAO in Rome.
Chile is sending some samples outside the country for more genetic sequencing to confirm that it matches the pandemic strain, Lubroth said. "As a scientist, I want to touch, smell, feel, taste it" before agreeing that it's a match, he said.
There are some encouraging signs that this particular outbreak remains mild. Egg production and water consumption among the birds dropped — prompting the company to take action — but the birds aren't terribly sick, let alone dying in large numbers, Lubroth said.
"My understanding is that with the ones that were sick, it was a very mild disease," Lubroth said. "It's significant in that we don't need to recommend any drastic measures, as far as culling the population of turkeys. Let them go through their illness and recover — seven to 10 days — and if they are sound and healthy, they could enter the food chain."
Sopraval veterinarian Andrea Campos said that won't happen because the outbreak has been limited to birds raised to lay eggs, not those being fattened for meat.
"In all of the birds raised to be fattened to produce meat, we have not found any illness. This is an illness entirely limited within a reproductive group," Campos said.
Lubroth praised the company and the Chilean ministries for the actions they've taken.
"If it were highly virulent then we would recommend stronger measures," Lubroth added.
Containing the outbreak
Chile, meanwhile, is acting to contain the outbreak by limiting the turkeys' contact with people and wildlife, Lubroth said. But given the mildness of this particular outbreak, he said, "I don't see that there is going to be a large risk from what we know today of this type of transmission occurring."
U.S. health officials said they remain wary of the possibility that swine flu will mutate by mixing with bird flu or other forms of influenza. But they haven't received any reports of a dangerous mutation yet, and the fact that the virus can spread to turkeys was not all that surprising, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaking at a Friday news conference in Atlanta.
The Chilean report "did not raise any great concerns among us," Fauci said.
The U.S. Department of Agriculture has a longstanding avian influenza surveillance program that it says would detect any H1N1 virus outbreak in U.S. poultry. The USDA recently infected ducks, chickens, turkeys and quail in lab experiments, and none became clinically ill. Low levels of the virus infected the quail, but the disease did not spread, the agency said this week.
In Chile, the virus has infected at least 12,000 people and killed 128. Throughout the Americas, as of Aug. 14, 105,882 confirmed cases were reported from all 35 countries, including 1,579 deaths in 22 countries.