More H5N1 Media Spin In Korea
Recombinomics Commentary 10:24
April 25, 2008
A Korean soldier who was involved in the culling process of poultry infected with bird flu has been found to be carrying a less deadly variant of avian influenza.
According to the Korea Center for Disease Control and Prevention, the corporal, identified only by his surname Cho, is not likely to be infected with the deadly strain of H5N1.
Authorities are also linking Cho's earlier symptoms of high fever to bacterial pneumonia.
The above comments on the status of the H5 positive soldier with confirmed pneumonia does not make sense scientifically or conceptually. The soldier was a culler of HPAI H5 positive chickens and ducks. To date Korea has described 11 outbreaks this season and all are HPAI H5. Six have been further characterized as HPAI H5N1, which is a deadly strain. The HPAI determination is based on the HA cleavage site. Last season the H5N1 in Korea was clade 2.2 (and was the Uvs Lake version of the Qinghai strain). That clade has an HA cleavage site of GERRRKKR and it is likely that all HPAI, including the strain that infected the soldier, will have GERRRKKR.
Thus, the claim that the H5 is not the deadly strain appears to be based on the quick recovery of the patient. However, similar quick recoveries were seen last season in Egypt. In the spring of 2007, only one in seventeen cases was fatal and most responded quickly to treatment. Moreover, many did not develop pneumonia. Thus, mild cases of clade 2.2 H5N1 have been documented.
If confirmed again, the H5N1 infection would be South Koreas first case meeting the WHO definition. In the past, confirmation of the first case in a country was frequently linked to a cluster. Moreover, the cluster was linked to one of a long series of testing shortfalls.
In 2005 the index case for Cambodia had been collecting dead bird prior to developing a fatal infection. He was never tested, but his sister became ill and was eventually brought to Vietnam for testing. After she died, she was H5N1 confirmed, so she was the first official case for Cambodia.
In 2005 siblings in Hunan China developed symptoms, One died and the other recovered, but initially both tested negative. Eventually a rise in antibody levels was used to show that at least one was H5N1 confirmed.
In 2005 the first case for Indonesia was the father of the index case. Initially samples were not collected from the index case for the cluster. Eventually antibodies were determined for two samples. Both were strong positives (titers of 640 and 1280), but since the second collection was only two fold higher than the first collection, the patient wasn’t an official case (although a early collection or a second collection more than 3 days after the first collection would have created a positive. The third fatality infected sibling was not tested.
In 2006 the first clade 2.2 infected paients were reported. In Turkey the first confirmed cases were siblings, but although three of the four were unconscious by the time they were tested in Van, all four initially tested negative. It was only after the three unconscious sublings began to die that they were declared H5N1 positive. The youngest sibling, who recovered, was never H5N1 confirmed.
The outbreak in Turkey was followed by Iraq. The index cases was said to have symptoms that exactly matched those of the siblings in Iraq. However, initially she was said to have died from a heart problem, a diagnosis that was supported by WHO. When her uncle developed symptoms, both were declared H5N1 positive.
Turkey was followed by Azerbaijan, and the cardiac diagnosis was used on the index case there also. After relatives and a friend began to die, the index case as well as relatives and a friend were declared H5N1 positive.
In 2007 the first H5N1 in Nigeria was reported. However, testing of the index case returned equivocal results, although her daughter was H5N1 positive. The index case was never confirmed.
In 2007, the first cases in Pakistan were brothers. Although one fatal case was confirmed, the index case as well as another brother tested negative by WHO affiliates initially. The other fatal case was never tested. Eventually, two of the brothers were confirmed by antibody tests, because the original samples had degraded and were PCR negative.
Thus, as detailed above, the vast majority of index cases were in clusters, although in most cases at least one of the fatally infected cluster members was not confirmed. However, the case in Korea also has similarities to the H5 infected geese on Prince Edward` Island (PEI) in Canada. Like the soldier, only one positive was reported and the initial report was H5 PCR confirmed. The three dead geese had been on a farm and displayed neurological symptoms. They were dead the following day. Ten days later a news conference was called to announce the H5 positive result. Since H5 rarely kills waterfowl, the likelihood that the geese were H5N1 positive was high. All birds on the farm were culled and the owners offered Tamiflu. However, after the other birds were found to be negative, the national labs in Winnipeg announced that the sample from PEI had degraded and the H5 results could not be confirmed. Consequently, there was no OIE report filed, and Canada and North America remained H5N1 free.
Thus, the history of index cases in a variety of countries remains clouded at best, even in high profile clusters.
More detail on testing results from the H5 infected soldier will be useful.
More media spin will not.
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