Wastewater surveillance of influenza activity: Early detection, surveillance, and subtyping in city and neighbourhood communities

Abstract

Recurrent epidemics of influenza infection and its pandemic potential present a significant risk to global population health. To mitigate hospitalizations and death, local public health relies on clinical surveillance to locate and monitor influenza-like illnesses and/or influenza cases and outbreaks. At an international level, the global integration of clinical surveillance networks is the only reliable method to report influenza types and subtypes and warn of an emergent pandemic strain. During the COVID-19 pandemic, the demonstrated utility of wastewater surveillance (WWS) in complementing or even replacing clinical surveillance, the latter a resource-intensive enterprise, was predicated on the presence of stable viral fragments in wastewater. We show that influenza virus targets are stable in wastewaters and partitions to the solids fraction. We subsequently quantify, type, and subtype influenza virus in municipal wastewater and primary sludge throughout the course of a community outbreak. This research demonstrates the feasibility of applying influenza virus WWS to city and neighbourhood levels; showing a 17-day lead time in forecasting a citywide flu outbreak and providing population-level viral subtyping in near real-time using minimal resources and infrastructure.

Influenza transmission dynamics quantified from RNA in wastewater in Switzerland

“…Wolfe et al [14] established that influenza A virus (IAV) particles in wastewater correlated well with incidence rates from two wellcharacterized outbreaks on U.S. university campuses. Mercier et al [15] similarly quantified IAV particles in wastewater at the municipality scale in Ottawa, Canada. They established that IAV concentrations in wastewater correlated well with municipal surveillance data when lagged 17 days, meaning wastewater was an early indicator of transmission dynamics in this system.…”

Influenza transmission dynamics quantified from wastewater

“…Wolfe et al (2022) established that influenza A virus (IAV) in wastewater correlated well with incidence rates from two well-characterized outbreaks on U.S. university campuses. Mercier et al (2022) similarly quantified IAV in wastewater at the municipality scale in Ottawa, Canada. They established that IAV concentrations in wastewater correlated well with municipal surveillance data, with the wastewater data evidently leading clinical surveillance data by 17 days.…”