TORONTO (Canadian Press) — A turkey breeding operation in southern Ontario has been hit by the H1N1 virus, the province's chief human and animal health officials reported Tuesday. It is only the second time turkeys have been reported to have been infected with the pandemic virus.
The outbreak likely poses no immediate threat to human health, and in particular should not have an impact on the safety of the food chain, the officials said, noting influenza cannot be contracted from well-cooked meat.
But experts do worry about the possibility that mutations could occur if flu viruses jump from one species to another and back again.
And some also expressed concern that news of the discovery could turn some consumers off turkey, even though in terms of flu transmission people probably pose a bigger risk to livestock right now than the other way around.
"From my perspective as a veterinarian, I see the danger being to the economic well-being of the animal industry that's involved, and in food security — having food," said Dr. David Halvorson, an avian influenza expert at the University of Minnesota.
The finding was announced by Dr. Arlene King, Ontario's chief medical officer of health, and Dr. Deb Stark, the province's chief veterinarian, both of whom refused to identify the affected turkey operation.
But their efforts to shield the company turned out to be futile. An industry group, the Turkey Farmers of Canada, posted a news release on their website announcing the outbreak had been discovered on a farm near Kitchener owned by Hybrid Turkeys.
Later, the company confirmed the report. Dr. Helen Wojcinski, a veterinarian and Hybrid's manager of science and technology, said turkeys in one barn on one farm experienced a drop in egg production — the telltale symptom of influenza infection in turkeys.
The barn, which contained 3,500 turkeys, is under quarantine. Wojcinski said it is expected the outbreak should run its course in about two weeks, at which point a decision will be made about what to do with the turkeys.
The birds are not free-range, meaning they live indoors under high biosecurity conditions. Wojcinski said the most likely source of the infection was a person with access to the barn.
King said local health officials are interviewing 19 people who had contact with the operation, trying to determine who might have brought the infection in to the birds — and if anyone contracted it from them.
So far one person has been identified as having had influenza-like illness, she said, though it's not yet known if the person actually had the pandemic virus. Nor is it clear whether the person's illness predated the outbreak among the turkeys or followed it.
King said the incident serves as a "clarion call" to poultry and other livestock workers that they should get vaccinated with both seasonal and pandemic flu shots in order to lower the risk of flu transmission to the animals with which they have contact.
"We want to limit the amount of circulation (of H1N1) in the human population for obvious reasons and we want to try to avoid or minimize the possibility of transmission between people and animals and back again," King said.
The finding was confirmed by the National Centre for Foreign Animal Diseases in Winnipeg, which compared amino acid sequences from three of the virus's genes to those of the pandemic virus, said Dr. Jim Clark, national manager of disease control for the Canadian Food Inspection Agency's terrestrial animal health division.
Clark said the lab is currently trying to grow virus from samples taken from the turkeys to do a full comparison, but CFIA feels confident the virus that caused the outbreak is the pandemic H1N1.
The finding will be of keen interest internationally. While swine producers in a number of countries have reported finding the new H1N1 virus in pigs, the only other report of infected turkeys came from Chile, in August. Some experts have privately questioned whether that finding was real or the result of contamination of specimens.
Announcement of the outbreak comes just days after the publication of a study that suggested turkeys are not susceptible to the pandemic virus. The work, done by researchers in Italy, was published late last week in the online journal Eurosurveillance.
Well-known influenza researcher Dr. Ilaria Capua and colleagues at the OIE collaborating centre for infectious diseases at the human-animal interface in Venice tried to infect turkeys with the new H1N1 virus. The OIE is the acronym used by the Paris-based World Organization for Animal Health.
Turkeys are generally very susceptible to influenza viruses and one would expect to see illness among birds if they became infected with a flu virus, Capua said in an interview Tuesday.
But while her team exposed turkeys to massive doses of H1N1 virus, they saw no evidence of infection in the birds. Nor did they find any evidence of virus in the lungs, blood or tissues of the turkeys.
Capua said teams of researchers in Britain, Germany and the U.S. have also tried to experimentally infect turkeys, also without success.
She said a lot of questions need to be answered about the new discovery in Ontario, including whether the full genetic sequence of the virus matches the pandemic virus.
"Before we say that this virus can spill into turkeys or into birds, I would really make sure that it's the right virus. And that there's no possible concern about any human error or contamination and that all the internal genes have been sequenced," said Capua.
But unpublished work from Canada suggests turkeys can catch this virus. Clark said scientists at the National Centre for Foreign Animal Diseases were able to infect turkeys with the pandemic virus.
"Since we know that the genetic makeup of the virus does have some avian components to it, it's not surprising to us that we have a poultry flock — a turkey flock — that is infected," he noted.
Halvorson, who said Minnesota has seen swine influenza outbreaks in turkey operations frequently over the last 20 years, said the new pandemic virus is posing real challenges for livestock producers.
While the female turkeys used for breeding purposes have shown themselves to be "exquisitely" sensitive to influenza viruses of both swine and avian origin, there's never before been evidence of the birds being infected with human flu viruses.
"We've never, ever found that or suspected it of happening. So this is kind of new, you know," he said. "For both the turkey industry and the swine industry, it's quite new. How do you protect your animals from a human infection?"