Bird Flu in Wild Birds in Canada
Recombinomics Commentary
May 12, 2006
Specialists from Wetlands International, who were deputized by the Food and Agriculture Organization, sampled 7,500 African wild birds last winter in their search for the disease. They found no H5N1, Mr. Hagemeijer said.
The above comments and similar remarks by various wildlife and wetlands conservation groups has been widely quoted as evidence that wild waterfowl play a minor role in the spread of H5N1. H5N1 bird flu was largely limited to China and countries in east and southeast Asia prior to the massive outbreak at Qinghai Lake last May.
After May, 2005 the Qinghai strain of H5N1 spread to Russia, Kazakhstan, Mongolia, and a number of countries in Europe, the Middle East, and Africa. The spread followed migratory bird flyways, but comments by bird conservation groups for the past 12 months have minimized the role of migratory birds.
The chief arguments have been tightly linked to negative data generated by these groups or other government surveillance groups like DEFRA. These groups claim to have screened thousands or tens of thousands of wild birds and H5N1 is reported as non-existent or minimal.
Negative data however, provides little useful information unless it is accompanied by positive data demonstrating that the collection and testing procedures are valid. The positive control for such data is low pathogenic avian influenza (LPAI), which is common in wild waterfowl. The data from DEFRA indicated that only two birds were positive for LPAI, and virus was not isolated from either. These data cast significant doubt on the DEFRA claim that only one bird of 7500 tested was positive for H5N1.
Canada has an ongoing avian influenza surveillance program and results are publicly available. The data for H5, H7, and avian influenza of all serotypes is available by location or species, and the data clearly show why the negative data by DEFRA, government agencies, and bird conservation groups are highly suspect.
In the Canadian study, bird flu was found in 1605 of the 4673 wild birds tested. This is in marked contrast to 3 positives in 7500 birds tested by DEFRA. The wildlife groups have not reported any LPAI detection in their testing. In the Canadian study, LPAI was detected in all species in which 25 or more were tested as indicated below.
These data raise serious questions about the credibility of the negative data on H5N1 in wild birds.
Below are number of birds positive for bird flu over number of birds tested (species with >25 birds tested)
American Black Duck 98/297
American Crow 4/51
American Wigeon 33/101
Blue-winged Teal 107/437
Gadwell 1/36
Green-winged Teal 51/225
Hooded Merganser 7/26
Mallard 1149/2612
Northern Pintail 26/135
Redhead 19/225
Ring-necked Duck 8/51
Rock Dove 2/33
Wood Duck 66/104
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