Caliciviruses: A major cause of foodborne illness

The public health impact of infections by human caliciviruses (HuCVs) is increasingly being recognized. The Norwalk-like viruses (NLV) are the most common cause of outbreaks of nonbacterial gastroenteritis and the most recognized foodborne viral etiologic agents. Factors that contribute to their high burden of infection are low infectious dose, stability in the environment, the diversity of strains, and the lack of long-term immunity to infection or illness. The recent development of sensitive molecular techniques for diagnosis, quantification, and characterization of these agents has led to the recognition of the importance of NLV infection. Future applications of these approaches to understanding modes of transmission and the effectiveness of control measures holds promise for improved understanding of the epidemiology of HuCVs, as well as important control measures for foodborne transmission. This report reviews what is currently known and understood about human caliciviruses regarding foodborne transmission.