Chile Confirms Turkeys Caught Swine Flu from Humans

Health experts fear that a more virulent influenza could result if the swine flu virus mingles with the bird flu virus, which is more deadly but not as easily transmitted.

The Chilean farming agency SAG first detected the H1N1 virus in turkeys at two private turkey plants belonging to the same company near the port city of Valparaiso. The farms, owned by Sopraval SA, were placed under quarantine on August 13 as a precaution. The premises were disinfected but the birds were not treated.

At a Sopraval turkey farm near Valparaiso the birds are kept in enclosed buildings. (Photo courtesy Sopraval)

Dr. Julio Garcia Moreno, who heads the Biomedical Department at the Chilean Institute of Public Health, the national reference laboratory, says after confirming the virus outbreak Chile communicated the finding to the World Health Organization.

A total of 36,585 turkeys were sickened by the H1N1 virus, but no birds died as a result. These turkeys were not raised for consumption but for egg production. The virus was detected because of behavior changes and lower rates of egg laying. As with pigs, there is no risk to people from meat consumption. Twenty days after the beginning of the first event, a recovery in the laying rate was observed.

The source of the outbreak is considered "unknown or inconclusive," but Chilean officials noticed that prior to the appearance of clinical signs, some birds were exposed to people showing respiratory symptoms.

Dr. Moreno said his agency's analysis of the virus conducted Saturday showed close genetic similarity to a California strain and 100 percent similarity to the strains circulating in Chile in human cases. "This week, we will analyze the complete genome," he said.

On June 11, the World Health Organization, WHO, declared global pandemic of the novel H1N1 swine flu. As of this week, more than 182,000 laboratory confirmed cases of the pandemic influenza have been reported in 177 countries and territories. At least 1,799 people have died.

As more and more countries have stopped counting individual cases, particularly of milder illness, the case number is significantly lower than the actual number of H1N1 cases that have occurred, said the world health body.

The appearance of the H1N1 virus in turkeys is a concern, Dr. Moreno said, due to "the possibility that this may happen in Asia or Africa under conditions of co-infection with H5N1 virus."

The Sopraval turkeys recovered. (Photo credit unknown)

The H5N1 virus is avian influenza, the bird flu, which has already caused the deaths of hundreds of millions of poultry and 262 human deaths in 11 countries since the latest outbreak began in December 2003.

Health experts worry that the H5N1 virus – if given enough opportunities – will develop the characteristics it needs to start another influenza pandemic.

The virus has met all prerequisites for the start of a pandemic except one - an ability to spread efficiently and sustainably among humans.

While H5N1 is presently the virus of greatest concern, says WHO, "the possibility that other avian influenza viruses, known to infect humans, might cause a pandemic cannot be ruled out."

The H5N1 virus can improve its transmissibility among humans by what WHO calls a “reassortment” event, in which genetic material is exchanged between human and avian viruses during co-infection of a human or pig.

The World Health Organization warns, "Reassortment could result in a fully transmissible pandemic virus, announced by a sudden surge of cases with explosive spread."

But at the Centers for Disease Control and Prevention in Atlanta, Georgia, officials said they were not concerned by the Chilean report.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said, "It's not surprising we see this infecting turkeys because the bird, swine, human access with influenza is well-established. ... The report of turkeys being affected in Chile, although it's of interest, did not raise any great concerns among us."

Copyright Environment News Service, ENS, 2009. All rights reserved.