Commentary
Additional
H5N1
Spread To Central Assam Raises Concerns
Recombinomics Commentary
18:48
December 18, 2008
The above comments suggest H5N1 has spread throughout Assam (see updated map). H5N1 has already been confirmed at the northwest and northeast corners, and the above areas fill in the areas in between. Confirmation has been slow, but culling groups are already stretched thin battling H5N1 in regions where H5N1 has already been confirmed.
Included in the confirmations were crows in Assams largest city, Guwahati, and extensive culling in the city is ongoing (see zoomed map). The outbreak in and around the city has led to culling in adjacent regions in Meghalaya.
The testing of wild birds is far from ideal, so the true spread of H5N1 is likely to be markedly greater than the confirmed areas or the areas with unnatural poultry deaths. Wild birds are being tested via cloacal swabs, which generally yield false negatives fro the Qinghai strain (clade2.2), which is the strain previously reported for India and Bangladesh.
The new outbreaks suggest the H5N1 spread has been rapid and will likely spread to the south as the weather cools. Last season most of the spread was in January and February, so more spread to the south is likely.
The confirmation of H5N1 in dead crows in Guwahati is consistent with results in Bangladesh last season, and suggests the hundreds of dead crows in Malda signal the spread of H5N1 to wild birds, which lead to local spread.
Excessive poultry deaths have been reported for areas north of the outbreak in Englishbazar in Malda, and there are rumored deaths to the south in Murshidabad. In addition to these areas in India, Bangladesh has reported multiple outbreaks in the north as well as the area around Dhaka.
Thus, continued spread of H5N1 is expected and this spread may extend to new areas that have not previously reported H5N1.
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