Here, we report the diversity of amantadine-resistant mutants among avian influenza A viruses with pandemic potential (H5, H6, H7, and H9 hemagglutinin subtypes). Drug-resistant variants were not detected among 1979-83 isolates, whereas 31.1% of H5 and 10.6% of H9 strains from Southeast Asia isolated in 2000-04 carried mutations in M2 protein. In North America, resistant variants occurred among H7 viruses only (16.4% of those tested). H6 viruses were amantadine-sensitive. These findings prompt concern regarding the control of pandemic influenza, the possibility that the next pandemic virus will be amantadine-resistant and the need to monitor the use of the drug in poultry. © 2005 Elsevier Inc. All rights reserved.
Ilyushina, N. A., Govorkova, E. A., & Webster, R. G. (2005). Detection of amantadine-resistant variants among avian influenza viruses isolated in North America and Asia. Virology, 341(1), 102–106. https://doi.org/10.1016/j.virol.2005.07.003