Posted on 10/14/2005 2:05:41 PM PDT by paulat
Bird flu virus shows signs of evading newest drug
By Maggie Fox, Health and Science Correspondent
1 hour, 22 minutes ago
WASHINGTON (Reuters) - The feared avian influenza virus is showing signs it can evade the drug considered the first line of defense against bird flu, researchers They found so-called resistant strains in a Vietnamese girl who recovered from a bird flu infection after being treated with Tamiflu. They also found evidence she was directly infected by her brother and not by chickens, a rare case of human-to-human transmission of the virus.
When bacteria and viruses develop resistance to a drug, it means higher doses of the drug are needed to eradicate or control an infection. Ultimately it means the drug will stop working.
This has happened with many antibiotics, starting with penicillin, and is common among AIDS drugs.
The finding illustrates the need to find and use other drugs to treat influenza and to work quickly to develop a vaccine, the researchers said.
"I don't think we need to panic based on this finding," Yoshihiro Kawaoka of the University of Wisconsin-Madison, who led the study, said in a telephone interview.
But the report, to be published in the journal Nature next week, is bad news for doctors around the world who already have precious little in the arsenal against bird flu should it become a human disease.
"This is the first line of defense," Kawaoka said. "It is the drug many countries are stockpiling, and the plan is to rely heavily on it."
The H5N1 strain of avian influenza is considered by health experts to be the biggest single disease threat to the world. Since surfacing in Hong Kong in 1997, it has spread in flocks of poultry across Asia and is now in Turkey.
It does not yet move easily from birds to humans but it has infected 117 people in four Asian countries and has killed 60 of them, according to the World Health Organization.
WHO believes it will eventually acquire the ability to move easily from human to human and that when it does, it will cause a pandemic that will sweep the world in weeks or months and kill millions if not tens of millions of people.
STOCKPILING SUPPLIES
Countries are stockpiling supplies of Tamiflu, an antiviral drug known generically as oseltamivir invented by Gilead Sciences and made and marketed by Swiss drug giant Roche Holdings.
They are to a lesser degree buying up supplies of Relenza, developed by Australia's Biota Holdings and marketed by GlaxoSmithKline. Known generically as zanamivir, this drug is also effective against avian flu but is given via the nose and considered less desirable than a pill like Tamiflu.
An older flu drug called amantadine is already considered to be of little use against H5N1 avian influenza. Work is proceeding on a vaccine but flu vaccines take months to make and cannot be formulated until after an epidemic has begun because they must use the precise strain of virus circulating.
Kawaoka, who is also at the University of Tokyo, worked with colleagues in Japan and Vietnam to analyze samples of virus taken from a 14-year-old Vietnamese girl, called "patient 1," who recovered from an H5N1 infection last March.
"Patient 1 had not had any known direct contact with poultry, but had cared for her 21-year-old brother (patient 2) while he had a documented H5N1 virus infection," Kawaoka and colleagues wrote in their report,
She had been given Tamiflu three days before she became ill, and then was treated with the drug when it failed to prevent her infection.
Kawaoka's team found several types of H5N1 virus in the girl's sample, some of which had developed genetic mutations to make Tamiflu virtually worthless against it.
"It is a mixture," he said. "Within the mixture we found virus that is highly, highly resistant. When you look at the virus as a whole, it is partially resistant," Kawaoka said.
"I think what is important here is that the vast majority of H5N1 viruses are still very sensitive to oseltamivir," Kawaoka said.
"Although our findings are based on a virus from only a single patient, they raise the possibility that it might be useful to stockpile zanamivir as well as oseltamivir in the event of an H5N1 influenza pandemic," the researchers wrote.
And it will be important to test the virus regularly to see if it is changing and becoming resistant to drugs, they said.
What flu was going around in late 1972 and early 1973?
My sister was born in January 1973, and a day or two after she and Mom came home from the hospital, Mom came down with the most virulent flu I'd seen (until the one she and Dad caught at Christmas 1999). Are you old enough to remember what strain that was?
Just don't order the fish.
In this case, don't order the chicken... or the duck.
There are some days when I actually appreciate my mutant abilities.
Just don't order the fish.
I liked "Leave it to Beaver's" mom in that movie, as a jive-talker.
I think that was the "Asian Flu" bug.
I'm not sure there's much we can do about it in modern society. Eliminating contact with other people and living in isolation isn't even remotely an option anymore.
...from Googling...I can just guess it was some kind of "Asian" or "Taiwan" flu.
Link please. You may be confusing amantadine with Tamiflu.
My never humble opinion, this scare is way overblown. The 1918 pandemic had the good luck to get going just as the appropriate "host soup" was almost perfectly in place. Hundreds of thousands of troops and hospital cases from the war were sharing very close quarters with at best primitive sanitation. Then just as it got a good start, this brreding ground suddenly dispersed, scattering disease vectors to the four corners of the globe, with the results now noted in history. Given this perfect storm launch, a fairly nasty strain of influenza killed more people than the war had.
Interestingly, this avian flu is now in a near perfect soup, with birds and people packed in together like cordwood in sanitary conditions that would send the average American housewife screaming to the store for cleaners of all sorts. That it has infected so few humans is not a resounding arguement for its inherent danger.
The idea this virus will leap in one iteration to an easily human to human transmissible disease is most unlikely. It is great for global drug companies and beauracracies looking for more money.
Two things strike me. If this bug does the unlikely, restrictions on movement and quaranteen of patients will do more to stop it than any drug. That is what killed the 1918 pandemic. As we have discovered with AIDS, we still don't have a lot in the way of effective treatment for viral pathogens. Vaccines, maybe, cures for active cases, not so much. Treatments, palliatives, stimulus for the body's immune system, but cures, NO.
I would go as far as preparing a plan for travel restrictions if necessary, but I would not spend a plugged nickel to get in line to buy overpriced Tamiflu, a drug of dubious value with a shelf life measurable in months.
Get a grip. Worry about your mortgage, your credit card bills, the war in Iraq, but at this point I worry more about panicky idiots squandering public monies on failed cures for a disease we ain't got than I worry about dying of bird flu.
Nevermind that. I wonder who, who, who wrote the book of love?
Oooh, and it makes me wonder . . . if there's a bustle in your hedgerow, don't be alarmed now!
Hey, speaking of, how's Mason?
...only if you remember to hit yer button...
Yes a hand full may have turned gray, so why does not anyone site the grave yards that is full of people who died from drugs and yes the silver works great for me and others.
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