Bird flu shows resistance to drug

The strain of flu scientists fear could spark a pandemic is showing signs of becoming resistant to an antiviral drug being stockpiled around the world, a warning that drugs being stored by governments might not be as strong a defense as hoped, flu experts say.

Tamiflu is one of just two antiviral medications that appear to be effective against the bird flu strain known as H5N1, which has circulated in Asia for nearly two years. Scientists report in the journal Nature that virus samples taken from a Vietnamese girl in February were found to be resistant to the drug.