Bird Flu Re-emerges in Turkey
Recombinomics Commentary
February 8, 2007
The ministry said in a statement that a quarantine zone was imposed on an area with a radius of 10 kilometers (6.2 miles) around the village of Bogazkoy, where 170 birds died, covering also two nearby villages.
The authorities were informed of chicken deaths in Bogazkoy on Monday.
"Detailed work is under way to determine the type of the disease," it said.
Veterinary experts have begun slaughtering birds in the village, which number 900 chicken, turkeys and ducks.
The disease is believed to have been brought by migratory birds.
The above comments on culling and linkage to migratory birds strongly indicate that the Qinghai strain of H5N1 has been reported again in Turkey. Turkey was one of the first countries in the region to report H5N1 in October, 2005. It was also the first country to confirm the Qinghai strain of H5N1 in people, in January of 2006.
Therefore, new reports of H5N1 in Turkey at this time of the year are not surprising. Egypt has been reporting H5N1 since September, and recently H5N1 was reported in Hungary, Krasnodar, England, and Pakistan. More reporting in the region is expected in the upcoming days.
The first human cases in Turkey had S227N, which is a change in the receptor binding that increases affinity for human receptors in the upper respiratory tract. Although high levels of H5N1 have been reported previously in the upper respiratory tract of patients in Vietnam and Indonesia, recent data indicates the receptor preference is associated with sneezing in ferrets, which may be related to ease of transmission.
The index case in Turkey was part of a large cluster. Although S227N was not detected in an isolate from the sister of the index case, this failure was likely linked to selection during virus isolation. Recently S227N in a patient in Vietnam was described, although S227N was only detected in one of three clones from that patient, even though all isolates were on dog kidney cells (MDCK).
S227N has also been reported in a patient in Egypt. H9N2 in the Middle East has donor sequences fro the acquisition of S227N, and the report of Qinghai isolates in the region with S227N raises the possibility that S227N will be detected again this season.
Other receptor binding domain changes in Qinghai isolates were detected last season in Iraq ands Azerbaijan, and this season in Egypt. More such changes are expected and are cause for concern.
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