Avian flu bug becoming more resistant to drugs
by January 12, 2009 2:55 pm 72 views
Researchers at the University of Colorado at Boulder say the avian flu virus is becoming more resistant to antiviral drugs, a troubling finding especially in a state with a large poultry industry.
According to the university research report, the avian flu (H5N1) is evolving a resistance to a group of antiviral drugs known as adamantanes, one of two classes of antiviral drugs used to prevent and treat flu symptoms.
The rise of resistance to adamantanes is linked to Chinese farmers adding the drugs to chicken feed as a flu preventative, according to a 2008 paper by researchers from China Agricultural University.
First detected in China in 1996, the avian flu has spread throughout Asia and to India, Russia, Pakistan, the Middle East, Africa and Europe by various carriers, including poultry and migratory waterfowl, said Andrew Hill, chief researcher on the UC-Boulder study.
According to the Centers for Disease Control in Atlanta, an avian flu pandemic could kill millions of people in America, infect 15 percent to 35 percent of the population and cost mort than $100 billion in economic damages.
“While H5N1 is not highly communicable to humans from birds or between humans, experts are concerned future evolution of this subtype or other subtypes, or genetic re-assortment between subtypes, could make an avian influenza strain more contagious with the potential to cause a pandemic,” the report noted.
The CU-Boulder study is the first to show H5N1 drug resistance to adamantanes arose through novel genetic mutations rather than an exchange of RNA segments within cells, a process known as re-assortment, Hill said in the report.
“As these adamantanes have gotten into nonhuman vectors like birds, the positive selection for resistance to avian flu is rising,” Hill said. “If Tamiflu is ever used in the manner of adamantanes, we could conceivably see a similar resistance developing through positive selection.”