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H5N2 In Korean Ducks
Recombinomics Commentary
December 22, 2004
>>About 9,000 ducks have been destroyed at the farm since quarantine officials detected the suspected H5N2 strain of avian influenza on December 1, it said, adding an isolation zone had been set up around the farm.
"It appears to be the first case of the H5N2 virus, although we are still waiting for a test result," a ministry official told AFP. "The area has been sealed off, with inspectors checking nearby farms for possible contamination."<<
The detection of H5N2 in South Korea on Dec 1 brings up several issues related to transparency as well as exchanges of genetic information among various isolates in the area.
The H1N1 and H9N2 WSN/33 related sequences in Korea swine were made public at about the beginning of Dec also, yet it is not clear that these sequences were being actively verified until they were brought to the attention of WHO and there still has been no official comment from WHO, FAO, or any other organization that should be monitoring early avian influenza danger signs.
The detection of H5N2 raises issues regarding reassortment and recombination with these newly discovered isolates. The H1N1 isolates in swine have an N missing the key glycosylation site that allows WSN/33 to sequester plasminogen, facilitating H0 cleavage in many tissue types. Combining this N1 with H5 from H5N2 could lead to a much more virulent strain.
However, sequence information regarding H5 isolates in Korea, Japan, and Taiwan has not been made public. None of these countries have made these sequences available at public data bases such as GenBank or Los Alamos even though the isolates were described almost year ago. These sequences are important in view of the H5 antibodies detected in Japan farm workers as well as the H1N1 and H9N2 sequences detected in swine in Korea (and H9N2 have also been detected in chickens in Korea this year).
The amount of recombination and reasortment of WSN/33 and avian H9N2 genes in swine in Korea has been extensive, leading to concerns regarding additional exchanges of genetic information with other isolates, such as the H5N2 described above.
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