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Sunday, June 26, 2005

Something To Pray About

Recombinomics has been documenting what seem to be alarming signals that bird flu in Asia (H5N1) seems to be evolving rapidly to a form that is far more contagious among humans. Officials are worried, because human cases have continued to increase over the last few weeks in Vietnam:
"This year, there doesn't appear to be a stop," said Klaus Stöhr, head of WHO's global influenza program in Geneva. "Every human case is worrisome because there is another chance for the virus to [mutate] and a higher chance for a pandemic to occur."

Stöhr said it was unclear why human cases have not receded this summer. It could be better surveillance or more instances of bird-to-human transmission. Or perhaps the virus has become more adept at infecting people.
No kidding. What is even more worrisome is that the virus has changed enough that test developed to detect it are now giving false negatives in Vietnam. We don't really know how many human cases there are:
Today Vietnam has acknowledged that these changes have lead to false negatives and the extent of H5N1 infections is highly than previously acknowledged. The admission in Vietnam suggests that false negatives were also generated in Thailand, since 2005 in Thailand is similar to 2005 isolates in northern Vietnam, where the number of mild human cases has markedly increased.

Since much of this change has only been recorded on western blots, the dramatic increases have not been reflected in the "official" numbers maintained by WHO. WHO has issued a press release indicating that these positives were "research" results and required confirmation by HI tests, which are said to not be possible in Vietnam because of a lack of a BLS-3 facility. The failure to include this data in the official totals, even though the samples were collected in March or early April is yet another example of how scandalously poor the H5N1 surveillance is, even in the country with the highest number of reported H5N1 cases. H5N1 changes not only affect tests designed to detect the virus, but these changes also affect the clinical presentation, which has been used to exclude testing of a large number of patients in Asia with "mysterious" disease.

Thus, at this point WHO has a very incomplete data base on where H5N1 is and isn't and how evolved the virus has become in 2005. These two glaring deficiencies will significantly impact efforts to control the 2005 H5N1 flu pandemic.
We aren't going to stop it; that much is clear from the incidents in China. But the recent data from Vietnam seem to indicate that the disease is becoming milder as it becomes more infectious to humans. If authorities succeed in stopping the chain of transmission for the severer outbreaks, the less fatal forms should be the ones that break out. We can only hope and pray for this outcome.


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