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H5N1 in Japanese Farm Worker
Recombinomics Commentary
December 22, 2004
>>The case confirmed in Japan was of an an employee at Asada Nosan Co.´s Funai Farm in western Kyoto prefecture (state), at the center of Japan´s outbreak in February.
He had a headache that lasted for several days but showed no other symptoms after spending a month spraying disinfectant around the farm from late February, the ministry said.
After the farm was disinfected, the Kyoto government took blood samples from about 86 people, including farm employees, firefighters and local government employees who took part in the operation.
The samples were examined by the National Institute of Infections Diseases in Tokyo.
On Friday, the government said blood samples from five people tested positive for the virus.<<
Although it is still not clear when the employee had symptoms, the case was clearly mild and quite different from H5N1 cases in Vietnam and Thailand. Although H5N1 was widely detected in Asia this year, all of the reported fatal cases have been in Vietnam and Thailand. These isolates, from human and animals, have a number of polymorphisms unique to Vietnam and Thailand. Other H5N1 isolates from Indonesia, Hong Kong, and many provinces in mainland China including Guangdong, Hubei, Jilin, Yunan, amd Hunan are closely related, but lacking the determinants mentioned above.
Unfortunately, sequences from Japan, Korea, and Taiwan have not been made public, even though the outbreaks were 10-12 months ago. Media reports on the Japan isolate indicated it was 97% homologous to a 1996 duck isolate from Guangdong, a full sequence would be much more informative. All of the H5N1 isolates from 2004 are fairly closely related to at least some of the genes from 1997 H5N1 isolates from Hong Kong as well as 2003 human isolates from Hong Kong, but the genes have reassorted and recombined and a pandemic vaccine against the 1997 isolates does not react well with the 2004 isolates.
The new flu season is associated with new infections in Vietnam, Thailand, Indonesia, and Korea, and comparisons between the new sequences and those from representative sequences from all countries with H5 outbreaks in 2004 would be useful.
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H5N1 in Japanese Farm Worker