Correlation between Influenza Cases and Antiviral Drug Concentrations in Environmental Waters

Abstract

Recently, anti-influenza drugs have been widely detected in Japanese water environments, particularly during seasonal influenza period. This article reports and discusses the occurrence and fate of oseltamivir and zanamivir in a sewage treatment plant and the Neya River water in Osaka during the 2010-2011 seasonal influenza using a newly developed solid phase extraction (SPE) method for simultaneous recovery of the drugs. High concentrations of zanamivir (ZH), oseltamivir (OP) and its active metabolite (OC) were detected in wastewater, treated effluent and river water. The observed ZH concentrations were approximately one-third and one-tenth of the OP and OC concentrations, respectively. The results strongly suggest that the drugs were not eliminated by sewage treatment or river water transport. Index values were calculated using reported influenza cases and drug dosing period and excretion time, and were correlated to the drug concentrations. The strong correlation shows that influenza cases can be effective to predict drug presence in environmental waters.