[Source: Antimicrobial Agents and Chemotherapy, full text: (LINK). Abstract, edited.]
The effect of oseltamivir carboxylate consumption on the emergence of drug resistant H5N2 avian influenza virus in mallard ducks
Jenna E. Achenbach 1 and Richard A. Bowen 2,#
Author Affiliations: 1Colorado State University, Fort Collins CO 80523, Departments of Microbiology, Immunology, and Pathology 2Biomedical Sciences
Oseltamivir carboxylate (OC) has been detected in environmental waters at varying levels during recent influenza seasons in humans, reflecting levels of usage and stability of this drug. In consideration of the role of waterfowl as hosts for influenza viruses that may contribute to human infections, we evaluated the effect of consumption of low doses of OC on development of oseltamivir-resistant influenza virus mutants in mallard ducks (Anas platyrhynchos) infected with two different low pathogenic (LP) H5N2 avian influenza viruses (AIV). We detected development of virus variants carrying a known molecular marker of oseltamivir resistance, (neuraminidase E119V) in 4 out of 6 mallards infected with A/Mallard/Minnesota/182742/1998 (H5N2) and exposed to 1,000 ng/L OC. The mutation first appeared as a minor population on days 5-6 and was the dominant genotype on days 6-8. Oseltamivir-resistant mutations were not detected in virus from ducks not exposed to the drug, or in ducks infected with a second strain of virus and similarly exposed to OC. Virus isolates carrying the E119V mutation displayed in vitro replication kinetics similar to wild-type virus, but in vivo, the E119V virus rapidly reverted back to wild-type in the absence of OC, and only the wild-type parental strain was transmitted to contact ducks. These results indicate that consumption by wild waterfowl of OC in drinking water may promote selection of the E119V resistance mutation in some strains of H5N2 AIV that could contribute to viruses infecting human populations.
#corresponding author: Richard.email@example.com
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