Featured Research

from universities, journals, and other organizations

Flu Virus Reported To Resist Drug Envisioned For Pandemic

Date:
October 15, 2005
Source:
University of Wisconsin-Madison
Summary:
An avian influenza virus isolated from an infected Vietnamese girl has been determined to be resistant to the drug oseltamivir, the compound better known by its trade name Tamiflu, and the drug officials hope will serve as the front line of defense for a feared influenza pandemic.

Scientists from the University ofWisconsin-Madison, working with colleagues in Vietnam and Japan, reportin a brief communication in next week's edition (Oct. 20, 2005) of thejournal Nature that a young girl, provided with a prophylactic dose ofthe drug after experiencing mild influenza symptoms, developed a strainof the virus that was highly resistant to the drug.

The findingsuggests that health officials - now stockpiling millions of doses ofthe drug to forestall a global outbreak of influenza and buy time todevelop and mass produce a vaccine - should also consider otheroptions, according to Yoshihiro Kawaoka, an international authority oninfluenza and the senior author of the Nature paper.

Recentreports indicate the federal government may spend billions of dollarsto stockpile as much as 81 million courses of Tamiflu to forestall apossible influenza pandemic. The government has already stockpiled anestimated 12 to 13 million courses.

"This is the first line ofdefense," says Kawaoka, a professor in the UW-Madison School ofVeterinary Medicine who holds a joint appointment at the University ofTokyo. "It is the drug many countries are stockpiling, and the plan isto rely heavily on it."

The drug would be used to slow the spread of influenza until a vaccine is developed, which may take up to six months.

Tamifluis delivered orally and works to impede the spread of the virus bybinding to and inhibiting one of the surface enzymes the virus uses toexit infected cells of a host. Once inside a host cell, the viruscommandeers the cell's reproductive machinery to make new infectiousparticles that go on to take over other cells. When the drug is atwork, Kawaoka explains, "the virus is still able to replicate inside acell, but is unable to get out and infect other cells."

Oseltamivir,which Kawaoka describes as an "amazing drug," is one of three compoundsproven to be effective against influenza. One class, derivatives of thecompound adamantine, would be less effective, as some flu viruses havealready evolved resistance to it. The other drug, zanamivir, which wasdeveloped prior to oseltamivir, is effective, but is formulated as apowder and requires that a clinician provide instructions for use.Thus, it is more cumbersome to administer than the orally deliveredTamiflu.

These flu-fighting drugs, says Kawaoka, are by no meansa replacement or alternative to a vaccine. Effective vaccines canconfer immunity, preventing the virus from gaining a toehold in thebody. But it is unlikely sufficient quantities of a vaccine can beproduced and stockpiled prior to the emergence of a new virus in humanpopulations.

If avian influenza does emerge and becomesinfectious from human to human - and nearly all experts agree that willhappen at some point in the future - an outbreak similar to the 1918influenza pandemic could occur. That pandemic killed as many as 50million people, more than died on all the battlefields of World War I.Scientists and vaccine manufacturers would be in a race against time toproduce enough doses to forestall disaster. Drugs like Tamiflu, used incombination with quarantine, would be intended to slow the spread ofthe disease until a vaccine is produced.

Kawaoka says there maynot be enough Tamiflu to go around even though countries arestockpiling it. The Wisconsin scientist says that will create a risk ofpatients sharing the drug and using smaller doses, which couldaccelerate the emergence of virus resistant to the drug and hamperefforts to contain the spread of the disease.

He says healthofficials should consider stockpiling zanamivir and recommending thatonly the therapeutic dosages of Tamiflu be administered to patients.

"We'vebeen watching for this change (in the virus)," Kawaoka says. "This isthe first, but we will see others. There's no question about it."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. Note: Materials may be edited for content and length.


Cite This Page:

University of Wisconsin-Madison. "Flu Virus Reported To Resist Drug Envisioned For Pandemic." ScienceDaily. ScienceDaily, 15 October 2005. <www.sciencedaily.com/releases/2005/10/051015091647.htm>.
University of Wisconsin-Madison. (2005, October 15). Flu Virus Reported To Resist Drug Envisioned For Pandemic. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2005/10/051015091647.htm
University of Wisconsin-Madison. "Flu Virus Reported To Resist Drug Envisioned For Pandemic." ScienceDaily. www.sciencedaily.com/releases/2005/10/051015091647.htm (accessed August 27, 2014).

Share This




More Health & Medicine News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Predicting Heart Transplant Rejection With a Blood Test

Predicting Heart Transplant Rejection With a Blood Test

Ivanhoe (Aug. 27, 2014) Now a new approach to rejection of donor organs could change the way doctors predict transplant rejection…without expensive, invasive procedures. Video provided by Ivanhoe
Powered by NewsLook.com
Better Braces That Vibrate

Better Braces That Vibrate

Ivanhoe (Aug. 27, 2014) The length of time you have to keep your braces on could be cut in half thanks to a new device that speeds up the process. Video provided by Ivanhoe
Powered by NewsLook.com
Smartphone App Tracks Your Heart Rate

Smartphone App Tracks Your Heart Rate

Ivanhoe (Aug. 27, 2014) A new app that can track your heart rate 24/7 is available for download in your app store and its convenience could save your life. Video provided by Ivanhoe
Powered by NewsLook.com
Stroke in Young Adults

Stroke in Young Adults

Ivanhoe (Aug. 27, 2014) A stroke can happen at any time and affect anyone regardless of age. This mother chose to give her son independence and continue to live a normal life after he had a stroke at 18 years old. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins