AFD - Possible H1N1 Mutations

[sharon sanders]

Tamiflu Resistant Strain Of Novel H1N1 Detected In Denmark



# 3407


One of our concerns has been with the novel H1N1 virus is, that like its seasonal flu cousin, it could pick up resistance to oseltamivir (Tamiflu).

Seasonal H1N1 went from almost 100% sensitive to the drug, to nearly 100% resistant, in a little over a year.
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Tamiflu is currently one of just two antiviral drugs in our arsenal that work against this pandemic virus. Losing it, and having to rely on Relenza (zanamirvir) alone, would constitute a major problem.

Not only are our stockpiles of Relenza much smaller, it is an inhaled powder, that is difficult for many people in respiratory difficulties to take.
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A couple of hours ago Dutchy on Flutrackers posted a Danish news article, translated to English, with this cryptic story.

caution - google translated

Dane resistant to Tamiflu
29. June 2009
The first case in the world of resistance to influenza drug Tamiflu in people with influenza H1N1 has been found in Denmark.

The person is now healthy, and there is no further evidence of infection with resistant virus, according to Statens Serum Institut.
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In the ensuing two hours we?ve received several confirmations of this report, including this Reuter?s Report.

Roche finds 1st case of H1N1 resistance to Tamiflu
Mon Jun 29, 2009
.
(Adds details)

ZURICH, June 29 (Reuters) - A patient with H1N1 influenza in Denmark showed resistance to Roche Holding AG's (ROG.VX) Tamiflu, the main antiviral flu drug, a company executive said on Monday.

"While receiving the drug, the patient appeared to develop resistance to it," David Reddy, Roche's pandemic taskforce leader, told reporters on a conference call on the Danish case. "This is the first report we have of it in H1N1."

The World Health Organisation has raised its pandemic flu alert on the H1N1 flu virus to phase 6 on a six-point scale, indicating the first influenza pandemic since 1968 is under way.

Common seasonal flu can resist Tamiflu and Reddy said a case of resistance in H1N1 was not unexpected, adding Roche has been working on strategies to counter such a development.
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While the discovery of one case of Tamiflu resistance is worrisome (although hardly unexpected), it doesn?t mean that Tamiflu is no longer an effective treatment for this pandemic virus.

For now at least, in the vast majority of cases, Tamiflu appears to remain effective in reducing the severity of novel H1N1 symptoms (it isn?t a cure).
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This is, however, a not-too-subtle reminder of how quickly an influenza virus can change.

Scientists will be watching closely to see if additional cases of resistance begin to show up.

For now though, this appears to be an isolated case.

 

[sharon sanders]

Re: AFD - Possible H1N1 Mutations

When Flu Strains Collide




# 3409

When two different flu viruses infect the same host at the same time ? and both viruses infect the same cell simultaneously ? they can swap genetic material and create a new `offspring? virus.

This is what is known as reassortment, and it is how new strains of influenza often are created. The novel H1N1 virus that has created our pandemic is a product of multiple reassortments.

The concern that many scientists have is that at some point the highly contagious ? but relatively mild - H1N1 virus will meet up with the hard to transmit ? but very deadly ? H5N1 bird flu and generate a reassortment.

Of course, you could get lucky and end up with a virus that is both mild and hard to transmit . . . but that isn?t the only possibility.
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Today we get a report on these concerns, particularly out of Indonesia, where the bird flu fatality rate is the highest of anywhere in the world.

Comments included are from Dr. C.A. Nidom, no stranger to readers of this blog, who is head of the Avian Influenza lab at Airlangga University in Surabaya and Indonesian Health Minister Supari.

Could swine flu mix with bird flu to create even deadlier strain?

Reuters
Monday, June 29th 2009, 1:48 PM

Tumbelaka/Getty
A hospital staff locks the gate at Sanglah hospital in Denpasar, Bali. Recent cases of H1N1 flu have raised concerns in Asian countries where H5N1 flu, or avian flu, is already entrenched.
What happens when flus collide?

Indonesia?s first cases of the new H1N1 flu, known as swine flu, have raised concerns that if the virus spreads it could combine with the entrenched and deadly H5N1 avian influenza to create a more lethal strain of flu.

Indonesian Health Minister Siti Fadillah Supari, who confirmed six new H1N1 cases on Sunday, said she was concerned about H1N1, widely known as swine flu, "marrying" with H5N1 avian flu.

Influenza viruses not only mutate quickly and unpredictably, but they can swap genes,especially if a person or animal becomes infected with two strains at once. The new H1N1 strain is itself a mixture of various strains, genetic tests show.

Even if this worst-case scenario did not occur, experts say populous, developing countries such as Indonesia, India or Egypt, where healthcare systems can be rudimentary, will suffer more deaths from the new virus.

(Continue . . .)
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This graphic from the FAO shows how two different avian viruses (H10N7 and H7N3) can meet up in a cell and produce a new virus, in this case H7N7.

Any host capable of catching both parent influenzas can become an incubator, or mixing vessel, for a reassortment. Pigs are thought to be particularly good hosts for this sort of mix and matching, although birds, humans, and other mammals are also potential vessels.

Pigs can catch human, avian, and swine influenzas.

How likely any of this is to happen is unknown.

We know it does happen, from time to time, because we can clearly see the results. But it obviously doesn?t happen often.

Otherwise we?d be neck deep in new viruses all the time.

The H5N1 virus has most certainly had opportunities to reassort with seasonal H1N1, along with other flu viruses, and to our knowledge, it hasn?t yet.

That doesn?t mean it can?t or it won?t, but it does suggest there are a lot of factors at play here . . . many of which we don?t completely understand.
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That said, reassortment is a legitimate concern, and something that scientists are constantly on the lookout for.