Posted by Yesterday there was a fairly long story from the wire service Canadian Press that wasn’t written by their ace flu reporter, Helen Branswell. It carried the byline of Greg Joyce. I’ll come back to why I mention this at the end of this post, but first, here’s what it was about:
Three of four of the most recent avian flu outbreaks in Canada have broken out in British Columbia’s Fraser Valley but despite years of trying to figure it out, they still can’t explain why the valley attracts the virus.
In the latest outbreak, 60,000 turkeys were culled on an Abbotsford, B.C., farm last week.
Tests so far indicate the virus has not spread to any other poultry producers within a three-kilometre quarantine zone.
That wasn’t the case in the valley’s first outbreak in 2004 when an H7-type flu transformed into a highly contagious strain.
Farm after farm was quarantined until finally about 15 million birds ? almost the entire valley poultry population ? was destroyed.
The second Fraser Valley outbreak in November 2005 saw two duck farms infected with the H5N2 strain of the virus.
In 2007, a highly pathogenic H7N3 strain was found in Saskatchewan on a farm that produced hatching eggs to produce broiler chickens.
Experts have difficulty explaining why the Fraser Valley has been hit so often but there are theories. (Greg Joyce, Canadian Press via Globe and Mail)
The rest of the story is about those theories and their implications. The story quotes two experts, Ron Lewis, chief veterinary officer for British Columbia and Sandra Stephens, veterinary program specialist with the Canadian Food Inspection Agency. Both speculate that the Valley is vulnerable for at least two reasons. The first is that it’s on the Pacific flyway, so virus carrying wild aquatic waterfowl are continually bringing new viruses. They note that infected birds are capable of shedding copious viral particles and various flocks will comingle at either end of their migration paths. The North American flyways are not isolated from other flyways, so the virus can move from one place to another, plausibly even from Asia or Europe. So why the Fraser Valley? That’s the second reason. While any poultry farm can be exposed to wild birds, the Fraser Valley has an unusually dense concentration of some 600 farms.
So those two factors suggest that these areas in Canada are at special risk from any avian influenza virus, including highly pathogenic H5N1. That’s a pretty scary prospect both from the economic and public health perspectives so raising it is itself potentially risky, at least from the political point of view. Don’t worry:
Mr. Lewis [the British Columbia veterinary officer] suggests it’s highly unlikely.
In countries where H5N1 occurred there are very close living conditions between poultry and people, he says.
?We don’t have that kind of proximity to wild and commercial ducks co-habiting in many cases that is present in those countries,? he says.
Moreover, Mr. Lewis says, the intense biosecurity measures introduced in Canada after the 2004 Fraser Valley outbreak are not practised in many of those countries.
?We now have a mandatory biosecurity program in place for all of the commercially-regulated poultry industry,? he says.
?The industry has achieved a very high level of compliance with those biosecurity protocols,? says Mr. Lewis, estimating the compliance rate at about 98 per cent of the industry.
If you think this argument through you’ll see it isn’t exactly coherent. At the least there are some missing pieces. The fact that humans live close to birds in places where highly pathogenic H5N1 is endemic has no bearing on whether it can be brought to Canada via long distance migratory birds. Large concentrations of industrial poultry operations is pertinent, but the Fraser Valley has that. There is perhaps a missing link that says wild birds infected with highly pathogenic H5N1 can’t make a long distance migration, but that is a matter of uncertainty and in any event wasn’t a case made in the story. There seems also to be a statement that wild birds and commercial poultry don’t co-habit in Canada the way they do where H5N1 is endemic, but then the argument about why the Fraser Valley has been hit three times in recent years by avian influenza viruses brought by migrating birds seems to be inconsistent.
For the same reason it is discordant to claim that Canada now has such stringent biosecurity measures for commercially regulated poultry that a problem is very unlikely. Then how come there have been two more, including the most recent. The answer is given at the outset: they don’t know. So how do they know an outbreak with highly pathogenic H5N1 is very unlikely? Same answer. They don’t.
We sometimes comment on reporting here because we like to reward good reporting and gently prod reporting that could be better. We can’t help but feel that if Helen Branswell had written this story it would have been better, for several reasons. Branswell knows the subject thoroughly and would know the questions to ask. That kind of experience doesn’t come over night, so there is time for a reporter like Mr. Joyce to school himself in the subject should he choose. The article is not terrible, by any means, but given the importance of the subject we’d like to have the kind of high level reporting an experienced reporter can bring to it. And Helen Branswell is a superior reporter with a proven track record of accuracy. A scientist can speak to her and be assured his or her comments will be correctly and clearly explained. Helen Branswell does this so effortlessly we often don’t notice the great skill it takes, but it’s noticed by those who deal with her regularly as a source. A consequence is that she probably has one of the best flu scientist rolodexes in journalism. She knows the players so she knows whom to call for what and when she calls they will take her all and answer her questions confident they will be properly reported. In this case we have a longish story based entirely on stenography from two government officials.
I hope Mr. Joyce isn’t discouraged by this criticism. As I said, it’s not such a bad job and I am holding him to a pretty high standard. On the other hand, high standards for reporting are unusually important on this subject. And they don’t get much higher than your colleague Helen Branswell’s work.
February 2, 2009
February 2, 2009
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