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Unreported H5N1 Bird Flu in China in 2005
Recombinomics Commentary
July 6, 2005
>> Phylogenetic analysis of these isolates and eight other H5N1 viruses, isolated from poultry markets in Fujian, Guangdong, Hunan and Yunnan provinces during 2005, indicated that the haemagglutinin (Fig. 1a), neuraminidase and nucleoprotein (data not shown) genes of the Qinghai viruses were closely related to the H5N1 virus A/Chicken/Shantou/4231/2003 (genotype V). <<
The above comment from tomorrow's Nature adds considerable evidence to suggestions that H5N1 is widespread in China and not being reported. Although China promptly reported the H5N1 outbreaks in Qinghai and Xinjiang in May and June, the prior OIE report was in the summer of 2004. Thus, prior to the three recent reports, there were no reported cases in China.
However, a report to ProMed asking for help on diagnosing dying geese in Fujian Province suggested many H5N1 infections were not tested and not reported. The symptoms sounding like bird flu. The geese had been dying since the fall of 2003 and replenishment with geese from nearby province produced the same results. It is not certain that the geese were dying from H5N1 because there was no testing, even when bird were dying in 2004 when China did report outbreaks throughout the country.
In view of the geese deaths in Qinghai and Xinjiang province and the genetic link to Shantou Province it seems likely that the untested and unreported geese were H5N1. As noted above, H5N1 was isolated from poultry markets in Fujian, Guangdong, Hunan, and Yunnan provinces in 2005.
Moreover, an upcoming report will describe the isolation of H5N1 from duck meat exported from Shandong Province to Japan in 2003, which is similar to the isolation of H5N1 from duck meat being exported from Shanghai to South Korea in 2001. In both instances multiple isolates were collected and the H5N1 was HPAI based on the sequences of the HA cleavage site and the ability to infect laboratory mice.
Thus, it would appear that much H5N1 is not detected or not reported in China. In addition to endangering the food supply, the under-reporting provides misleading information on China's vaccination program. Vietnam is adopting a program, but the only two countries with vaccine programs, China and Indonesia, have had mixed results. Indonesia has been declared endemic for H5N1 and the unreported outbreaks in China suggest H5N1 may be endemic there also, in spite of an aggressive vaccination program.
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