Oseltamivir in the Environment Can Induce Resistant Influenza Strains

During a normal influenza season, a considerable amount of oseltamivir is administered to patients. Oseltamivir carboxylate (OC), the active metabolite of oseltamivir, is excreted via the urine into the environment, but it is poorly degradable and accumulates. In Japan, where the consumption of oseltamivir is highest, OC concentrations of 58 to 293 ng/L have been detected in aquatic environments during seasonal influenza outbreaks. Using an animal model, researchers in Europe investigated whether such circumstances could pose a risk for the emergence of oseltamivir-resistant influenza viruses.

Mallard ducks were infected with an avian A/H1N1 influenza strain isolated from a wild duck. Uninfected birds were successively introduced to ensure t…