COLUMBUS, Ohio Influenza's ability to resist the effects of cheap and popular antiviral agents in Asia and Russia should serve as a cautionary tale about U.S. plans to use the antiviral Tamiflu in the event of widespread avian flu infection in humans, scientists say.
Researchers analyzed almost 700 genome sequences of avian influenza strains to document where and when the virus developed resistance to a class of antiviral drugs called adamantanes and how far resistant strains spread. The analysis suggests that widespread antiviral drug use can accelerate the evolution of drug resistance in viruses, and that resistant strains can emerge and spread rapidly.
The results should serve as a warning to those who consider Tamiflu the next great antiviral medication, the researchers say. Stockpiling Tamiflu has become a standard part of many government, business and health organization plans to prepare for a long-feared pandemic flu outbreak, especially in the event that avian flu mutates enough to infect and be easily transmitted among humans.
"We can't necessarily say what we've seen in adamantanes is predictive of what will happen with Tamiflu. But in the larger dynamic, perhaps it serves as a cautionary tale," said Daniel Janies, senior author of the study and an associate professor of biomedical informatics at Ohio State University.
"Fighting infection is an arms race, and if we're not smart about how we use our arms and understand the evolutionary implications, then we will have ongoing and accelerating problems with drug-resistant microorganisms."
Resistance to adamantanes among strains of seasonal influenza spiked in Asia in 2002, and by 2006 the agents were considered virtually worthless worldwide as a treatment for the flu because more than 90 percent of the strains had developed a resistance to the drugs.
With that knowledge, Janies and colleagues analyzed hundreds of avian flu genomes isolated from
|Contact: Daniel Janies|
Ohio State University