Drug Resistant Bird Flu in Southeast Asia

Resistance to the anti-viral drug amantadine is spreading more rapidly among avian influenza viruses of H5N1 subtype in Southeast Asia than in North America.

Investigators at St. Jude Children’s Research Hospital analyzed sequence data of the so-called M2 protein of avian influenza viruses, or bird flu, from different subtypes isolated in North America and Southeast Asia during 1991-2004, by evaluating the frequency of drug-resistant strains.

Sequence data refers to the makeup of a gene coding for a particular protein — in this case, the M2 protein. A properly functioning M2 protein is key to the virus’ ability to replicate.

The St. Jude researchers demonstrated that the largest proportion of Asian drug-resistant H5 and H9 avian influenza viruses occurred in China. The findings appear in the current online edition of Virology.