H5N1 Isolated in Illinois and Michigan
Recombinomics Commentary
November 21, 2006
The updated table of H5N1 positive samples in the United States indicates H5N1 has been isolated in from mallard duck samples collected October 19, 2006 in St Claire, MI and October 21, 2006 in Grundy, IL. This positives data is in marked contrast to the multiple isolates failures a week later in Grundy or failures four days earlier in Tuscola, MI.
The updated table indicates all positives since September 24 have been in hunter killed birds and most isolation attempts have failed. These failures raise question about the reliance on hunter killed birds and the failure to detect any H5N1 (low or high path) in dead or dying birds.
Isolation failures are likely to be linked to collection/transport/and testing procedures, and not be due to "dead" H5N1 at the time of collection, as had been indicated in earlier press releases..
Moreover, the failure to detect H5N1 in any dead or dying birds appears to be related to a lack of testing. The breakdown of samples tested shows that almost 35,000 live or hunter killed birds have been tested, but the number of dead or dying birds is less than 1000.
The failure to detect Qinghai H5N1 in live or hunter killed birds is not unexpected. Such detection has been rare and largely confined to areas of widespread infections in poultry, such as southern Siberia. Most countries in Europe did not find H5N1 until the beginning of this year, months after Qinghai H5N1 had migrated into the area. Moreover, the detection was in dead wild birds, not live or hunter killed birds.
In the United States there have been massive die-offs of waterfowl, which have largely been attributed to avian botulism. However, these die-offs have been in locations, such as the Great Lakes region, where multiple samples from live or hunter killed birds have tested positive for low path H5N1.
The failure to detect low path H5N1 in dead birds clearly demonstrates the limitations of a program that tests fewer than 1000 birds throughout the Continental United States, Alaska, and Hawaii.
The focus on birds that are unlikely to be H5N1 positive, and the very limited testing of dead and dying birds is cause for concern. This represents a fundamental failure to interpret the data generated in Europe and Africa, where H5N1 has been detected in poultry and fatal human infections, but detection of H5N1 in live or hunter killed wild birds has been extremely rare.
In Africa, media reports indicated over 15,000 wild birds were tested, and all were negative for H5N1, yet Qinghai H5N1 has been isolated and sequenced from birds and/or people from Egypt, Djibouti, Sudan, Nigeria, Niger, and Ivory Coast. Similarly, the vast majority of countries in Europe have only found H5N1 in dead wild birds or poultry.
On Prince Edward Island, only one of the four dead farm geese was tested, even though all four geese had symptoms of Qinghai H5N1 infection, including sudden death. H5 was confirmed by PCR, but the size of the insert was withheld.
The failure to test significant numbers of dead or dying wild birds in the United Sates and Canada remains a cause for concern.
Media sources
Phylogenetic Trees