ABSTRACT
NO R W A L K virus (NV), the prototype human calicivirus (HuCV), and re-lated HuCVs are the most widely recognized agents of outbreaks of foodborne and waterborne viral gastroenteritis. Early studies estimated that at least 42% of outbreaks of nonbacterial gastroenteritis in the U.S. were caused by such infections (Kaplan et al., 1982a). Currently the CDC estimates that greater than 96% of reported outbreaks of nonbacterial gastroenteritis characterized by nausea, vomiting, diarrhea, and an illness lasting 1-3 days are caused by HuCVs (Fankhauser et al., 1998). Similarly, in the Netherlands, a group of HuCVs, previously called small round structured viruses (SRSVs), were detected in 87% of all outbreaks of gastroenteritis reported to national epidemiologists in 1996, confirming the etiologic significance of SRSVs in outbreaks of gastroenteritis (Vinje et al., 1997). For this review, we wil l refer to NV and related viruses as human caliciviruses (HuCVs). This terminology wil l not distinguish HuCVs that can be separated into different genetic groups (see below).
