A sub-type (H5N1) of the highly pathogenic avian influenza virus is “readily inactivated” by chlorination of drinking water, according to a new study [1], as first reported September 7 on Effect Measure, a health-related Web site. Researchers from the US Environmental Protection Agency (EPA), the University of Georgia (Athens, GA) and US Department of Agriculture (USDA) found that the maintenance of a free chlorine residual of 0.52 to 1.08 milligrammes per litre (mg/L) was sufficient to inactivate the virus by greater than three orders of magnitude within an exposure time of one minute, according to the study.

Wild waterfowl spread the potentially deadly avian flu virus through their feces to poultry, and surface waters and potentially groundwaters can contain the virus, the researchers noted. The World Health Organization, concerned about its potential to spread to humans, has sought more information about the effectiveness of its inactivation.

[1] Rice, E.W. … [et al.] (2007). Chlorine inactivation of highly pathogenic avian influenza virus (H5N1). Emerging infectious diseases, vol. 13, no. 10. [Epub ahead of print]

Related news: Bird flu: health risks of transmission through water and sewage, Source Weekly, 26 Apr 2007

Contact: Eugene W. Rice, US Environmental Protection Agency, rice.gene@epa.gov

Source: WaterTech online, 10 Sep 2007

Tags: water quality, water-related diseases