July 31 Flu Update
The bombshell news today is a scientific study that attempted to replicate the mutations it would take for bird flu to become transmissible between people. The results (on ferrets) show that simple genetic changes are not enough. Good news. Of course, it could still happen, it's just not a simple process. And, replicating nature is always tricky. Still, this is important knowledge, because it means we may have more time than we suspected.But at a telephone news conference on Friday, an author of the study, Dr. Jacqueline M. Katz, said the scientists had tested only a few of the many hybrids that could be created. Further studies will examine more.Helen Branswell is on the story (yeah!). Here article gives strong voice to those who are talking about the study's limitations.
To test what might happen in nature, scientists would have to conduct what are called classical reassortment studies, where H5N1 and human flu viruses are allowed to co-mingle in a lab dish, producing naturally occurring offspring viruses. CDC is currently conducting such work with more current H5N1 viruses, Katz said.
The results could be different, said Dr. Frederick Hayden of the World Health Organization's global influenza program.
"We may see surprises and different gene reassortant patterns there. But until you actually do the experiments, that would just be a matter of speculation," said Hayden, who echoed Gerberding in saying this study doesn't offer any insight about how likely or unlikely H5N1 is to cause a pandemic.
CIDRAP also has this report.
The CDC officials were asked whether reassortment "dumbs down" or weakens the virus. Katz replied that the hybrids were less virulent than H5N1, but cautioned that the results apply only to the 1997 strain.
Gerberding commented, "The pandemics of 1957 and 1968 were caused by reassortant viruses. Those were not dumb viruses."
In answering other questions, Katz said some scientists believe the 1918 pandemic virus, unlike the 1957 and 1968 viruses, arose through slowly accumulating mutations in an avian virus rather than through a reassortment event. "We're looking at the approach of the 1957 and 1968 pandemics where there was a more sudden change," she said.
The most important lesson of the research so far, according to Katz, is "the knowledge that this process isn't simple, the procedure for the virus to acquire the properties of transmissibility."
Effect Measure weighs in. He hasn't read the paper yet, but notes that the headlines are racing ahead of the actual science, and that we still don't know much more than we did.
Recombinomics says that there were no results because it isn't reassortment that causes mutations anyway--its recombination.
This virus is capable of amazing parlor tricks and parlor tricks often look impossible until you see how they are done. Then they look simple.
There are now 131 cases "under suspicion" in Thailand.
Thailand (which has often boasted of its bird flu prowess) is blaming Laos for this outbreak.
Thai editorial reminds readers that even with past success, flu requires constant vigilance.
ProMed on Thailand's accusations (and an offer to "help" Laos), and Bulgaria's fear that it will get bird flu from Romania.
CIDRAP on Thailand.
Thai OIE report on bird outbreaks.
Novarax also has successful bird flu news.
UN FAO official says that fighting bird flu in Asia is hampered by a lack of aid.
A second roundtable was held in Rochester NY to prepare for the bird flu.
There is still one region in Russia which has active bird flu.
A Winipeg lab has been named a WHO reference lab.
Iowa is stocking up on Tamiflu.
Dr. Gerberding will give the Oppenhemier lecture at Los Alamos.
Effect Measure uses cuts in substance abuse funding to illustrate his point that fighting flu is all about an overall commitment to a public health infrastrcture.
Bird flu is effecting the quality of shuttlecocks.
posted by Orange @ 8:51 AM
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