How influenza pandemic control can lead to unpreparedness: modelling the ecotoxicity of pharmaceutical usage

Abstract

The global public health community has closely monitored the unfolding of the 2009 H1N1 influenza pandemic to best mitigate its impact on society. However, little attention has been given to the impact that our response to a pandemic might have on the environment. Antiviral and antimicrobial drugs prescribed to treat influenza and influenza-associated complications are poorly metabolized in vivo. Once ingested, they are subsequently excreted into wastewater in a biologically-active form potentially affecting the functioning of wastewater treatment plants (WWTPs) and contaminating receiving rivers. In order to evaluate this systemic risk we couple a global spatially structured epidemic model that simulate the quantities of drugs used during an influenza pandemic to a wastewater and river flow model applied to the Thames basin in Southern England. The model projects drug concentrations in the WWTPs and receiving rivers during pandemics of varying severity. Projections indicate no ecotoxicologic risk for a situation consistent with the 2009 H1N1 influenza pandemic. In the case of a more severe pandemic, however, between 5% to 40% of the length of the Thames River receiving WWTP effluent is projected to exceed thresholds for microbial growth-inhibition from antibiotics, introducing considerable risks of eutrophication, fish kill, and ultimately the contamination of drinking water abstraction points