H7 Bird Flu Identified in North Korea
Recombinomics Commentary
April 5, 2005
>> "We have a new situation because H7 has so far not occurred in Asia," Hans Wagner, a senior official with the U.N. Food and Agriculture Organization (FAO), told Reuters Television in Beijing after a week-long visit to North Korea.
"We don't know where the virus came from, so we have to trace back ... how did the virus come into the farms," said Wagner, who has played a prominent role in Asia's battle against the deadly H5N1 virus. <<
The detection of H7 in North Korea is cause for concern. Although not reported to FAO, media reports have indicated H7N1 has been detected in Indonesia along with H5N1. This is cause for concern because co-circulation can lead to dual infections by two sub-types resulting in rapid evolution via reassortment and recombination.
Bird flu is spreading in Indonesia, which has relied on vaccination approaches, although it is not clear that the vaccine includes H7N1. However, both H7N1 and H5N1 are spreading in Indonesia. Indonesia reporting to FAO has been mockingly poor. Their FAO reports suggest only a minor bird flu has happened between the end of February and beginning of March. Media reports describe outbreaks in December and a very large outbreak in all months of 2005 in Indonesia. Based on FAO comments, it sounds like they rely more on member reports than media reports, which based on past performance is a very poor choice.
H7 infections are a major concern because they can be efficiently transmitted from human-to-human. The widespread infections require a sensitive assay that involves agglutination of horse red blood cells. H7N7 equine infections have been noted previously, so H7 infections of mammals are not surprising.
In the Netherlands the 2003 H7N7 human infections were mild with only one fatality, but H7N7 was readily transmitted human-to-human. H7N3 infections in poultry in British Columbia last year also produced mild infections in humans. However, there is evidence for an H5N1 flight path that leads to related infections in Korea, eastern China, and Indonesia, raising the possibility of H5N1 and H7N1 co-circulating in all of those countries. In addition there have been H9N2, H3N2, H6N1 detected in South Korean live markets in 2003. The issue of WSN/33 / H9N2 recombinants and reassortants, as demonstrated in GenBank sequences, remains unresolved in South Korea, although these sequences have been in the public domain for over 5 months.
Thus, although H7 has been detected in North Korea, the potential of additional sub-types and novel reassortants and recombinants is quite real, as are the H7N1 Indonesian transmissions widely reported in the media, but not to FAO.
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