Inactivation of the Avian Influenza Virus (H5N2) in Typical Domestic Wastewater and Drinking Water Treatment Systems

Abstract

A highly pathogenic form of avian influenza of the H5N1 subtype emerged in Hong Kong in 1997, rapidly infecting wild and domesticated birds and spread among these populations to several countries in Asia, Africa, and Europe. This virus also proved capable of infecting humans. It was hypothesized that should human-to-human transmission of such a virus become efficient, domestic wastewater and drinking water treatment systems could become contaminated with the virus, potentially exacerbating the spread of this disease. The objectives of this work were to determine if a surrogate virus, H5N2 avian influenza virus (a virus with no history of infecting humans, hereafter referred to as "H5N2") is inactivated by UV radiation, chlorination, and anaerobic digestion. Infectious H5N2 was not detected in phosphate buffer and wastewater effluent at fluences greater than 10 mJ/cm² and at Ct values, based on free residual chlorine, greater than . In bench-scale anaerobic digesters, H5N2 dropped from an initial concentration of 10^{3.6 EID/mL to undetectable levels after 72 h.}