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H5 Detected in Saitama Japan
Recombinomics Commentary
August 18, 2005
Several chickens on a farm in Saitama prefecture, west of the capital, tested positive for the H5 type of bird flu, but studies are still being made to determine the subtype.
"We will have to wait for the final results to be certain, but it is unlikely to be the virulent strain of bird flu," an official with the Saitama prefectural government said.
He said the strain was likely to be the same as that reported earlier this year, which was the weak H5N2 strain.
More information on the basis for the statement that the H5 detected is H5N2 would be useful. The H5N2 isolated earlier in Japan was LPAI (Low Pathogenic Avian Influenza) and was closely related to H5N2 found in the Americas. Prior H5N1 isolated in Japan was HPAI (High Pathogenic Avian Influenza). If only antibody was detected, distinguishing the two H's is more difficult. However, if virus was isolated or detected via PCR, the sequence data will readily distinguish H5 from either H5N1 or H5N2.
The sequences of H5N1 from Qinghai Lake clearly show a close relationship with H5N1 isolates from Japan and South Korea. This close relationship was also found in isolates from Chany Lake in Novosibirsk, which involved recombination. Thus, it seems likely that the H5N1 migrating east from either Chany Lake or Qinghai Lake would find its way back to Japan and South Korea. H5N1 has already been detected in Mongolia and as more birds migrate to warmer regions, the likelihood of H5N1 being detected in Japan increases.
Since PCR determinations of the HA cleavage site are now routine lab procedures, it seems likely that Japan already knows if the latest reports are for H5N1 or H5N2. Release of that information would be useful.
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