Calicivirus—An Emerging Contaminant in Water: State of the Art

Abstract

There has been a noteworthy surge of interest with regard to the viruses known as human Caliciviruses (HuCVs) and their impact on water-borne disease. Recent epidemiologic studies in Europe combined with an active waterborne disease surveillance system in the United States has identified the Norovirus, a member of the HuCVs, as a prominent agent of waterborne disease. Current estimates suggest that upwards of 95–96% of nonbacterial gastroenteritis outbreaks of unidentified etiology may be due to HuCV. Moreover, there have been a number of documented waterborne outbreaks of Norovirus both in the United States as well as abroad. It is with the advent of advanced molecular techniques that we have begun to develop a strategy for the detection of this organism in various water matrices. However, because HuCV have not yet been cultured in the laboratory, it is difficult to conduct research on their fate in the environment and their removal or inactivation during water and wastewater treatment processes. Therefore, alternative approaches have included using recombinant Norwalk virus particles, indirect measures of inactivation based on molecular methods, or the culturable Feline Calicivirus as a surrogate. Results from these studies raise concerns about the mobility of HuCV in groundwater and their resistance to chlorine and monochloramine, and suggest that ultraviolet radiation may be an effective inactivation method. Additional research is needed to confirm these results and the methods employed as well as to investigate other treatment processes and environmental conditions.