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United States Department of Agriculture

Agricultural Research Service

Title: Inactivation of Feline Calicivirus and Adenovirus Type 40 by Ultraviolet Light Radiation

Authors
item Thurston Enriquez, Jeanette
item Haas, Charles - PHILADELPHIA PA
item Jacangelo, Joseph - LOVETTSVILLE VA
item Riley, Kelley - TUCSON AZ
item Gerba, Charles - TUCSON AZ

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2002
Publication Date: January 1, 2003
Citation: Thurston Enriquez, J.A., Haas, C., Jacangelo, J., Riley, K., Gerba, C. 2003. Inactivation of feline calicivirus and adenovirus type 40 by ultraviolet light radiation. Applied and Environmental Microbiology. 69:577-582.

Interpretive Summary: Disinfection is an important treatment barrier between drinking water consumers and viral gastroenteritis since the small size (~25-80 nm) of enteric viruses may permit their passage through conventional filtration processes. Concern for the formation of chlorinated organics and the effectiveness of chemical disinfectants has increased interest by the drinking water and wastewater industries to consider alternative disinfectants. One option that is receiving increased attention and produces few disinfectant by-products is ultraviolet (UV) radiation. Little information regarding the effectiveness of ultraviolet (UV) radiation on the inactivation of caliciviruses and enteric adenoviruses is available. Analysis of human calicivirus resistance to disinfectants is hampered by the lack of animal or cell culture methods which can determine their infectivity. The inactivation kinetics of enteric adenovirus type 40 (AD40), coliphage MS-2 and feline calicivirus (FCV), closely related to the human caliciviruses based on nucleic acid organization and capsid architecture, were determined after exposure to low pressure UV radiation in buffered demand free (BDF) water and groundwater (containing constituents which absorb UV light) at room temperature. Susceptibility to UV light is highest for FCV, followed by MS-2 and AD40 in BDF water and in treated groundwater. In groundwater, the kinetics of AD40 and FCV inactivation were not decreased by this water's constituents. According to this study, at least 99.99% inactivation would occur for FCV at the National Sanitary Foundation recommended dose of 40 mJ/cm2 (for potable water), however, not even 90% inactivation of AD40 would be achieved. This study's results provide a basis for the establishment of drinking water treatment guidelines for proficient application of low pressure UV radiation for calicivirus and adenovirus inactivation in low UV light absorbing waters.

Technical Abstract: Little information regarding the effectiveness of ultraviolet (UV) radiation on the inactivation of caliciviruses and enteric adenoviruses is available. Analysis of human calicivirus resistance to disinfectants is hampered by the lack of animal or cell culture methods which can determine their infectivity. The inactivation kinetics of enteric adenovirus type 40 (AD40), coliphage MS-2 and feline calicivirus (FCV), closely related to the human caliciviruses based on nucleic acid organization and capsid architecture, were determined after exposure to low pressure UV radiation in buffered demand free (BDF) water at room temperature. In addition, UV disinfection experiments were also carried out in treated groundwater with FCV and AD40. AD40 was more resistant than either FCV or coliphage MS-2 in both BDF and groundwater. The doses of UV required to achieve 99 % inactivation of AD40, coliphage MS-2 and FCV in BDF water were 109, 55 and 16 mJ/cm2, respectively. The doses of UV required to achieve 99 % inactivation of AD40, coliphage MS-2 and FCV in groundwater water were slightly less than in BDF water. FCV was inactivated by 99 % by 13 mJ/cm2 in treated groundwater. A dose of 103 mJ/cm2 was required for 99 % inactivation of AD40 in treated groundwater. The results of this study indicate that if FCV is an adequate surrogate for human caliciviruses, then their inactivation by UV radiation is similar to other single-stranded RNA enteric viruses such as poliovirus. In addition, AD40 appears to be more resistant to UV disinfection than previously reported.

Last Modified: 12/22/2014
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