More H5N1 Spread on South Korean Farms
Recombinomics Commentary 13:23
April 18, 2008
a suspected case had been reported at a duck farm in Gongju in South Chungcheong province, 130 km south of Seoul, suggesting the virus is spreading at its fastest rate since the country reported its first case in 2003.
The above comments describe further spread of H5N1 in South Korea (see satellite map). Although the outbreak may be the largest to date, there was no advanced warning. The large number of outbreaks is almost certainly linked to migratory birds returning to northern locations, but neither South Korea nor Japan detected H5N1 when the birds first came into the region, and Japan has not reported cases since the 2004 outbreak.
However, this is the third report in South Korea and all are likely due to wild birds. In 2003/2004 outbreaks were reported in South Korea and Japan. Sequences were closely related and were precursors to the clade 2.2 (Qinghai strain) identified in May, 2005 at Qinghai Lake. Similarly, the outbreak in late 2006 in South Korea were the Uvs Lake strain which is a clade 2.2.3 subclade that developed in the summer of 2006 in Mongolia.
The affected regions in South Korea lie along a migration route between Mongolia and South Korea and samples collected from areas frequented by migratory birds were positive for the Uvs Lake strain. The wild bird link is also supported by the H5N1 detected in Primorie in southeastern Russia, just north of Korea and just west of Japan.
Although Japan has not reported H5N1 since 2004, they have announce plans to use a pre-pandemic vaccine on first responders. Moreover, the possibility of vaccinating 20 million residents is under discussion.
Thus, the threat of H5N1 continues to grow, although surveillance programs continue to fail to detect H5N1 prior to outbreaks in domestic farms.
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