Noroviruses : Outbreaks, Control and Prevention Strategies

Norovirus (NoV) are the most common cause of sporadic and epidemic nonbacterial acute gastroenteritis worldwide, with an estimated 21 million cases occurring only in USA annually. NoV disease is characterized by a short duration of the symptoms, which can be severe for people in high risk groups, including children, elderly or immunocompromised patients. In fact, it causes up to 200,000 deaths in children under 5 years of age in developing countries. In addition, after the introduction of rotavirus vaccination programs, NoV are also the most common cause of pediatric gastroenteritis requiring medical care in the high- and middle-income countries. NoV is highly infectious, as even a few particles can cause disease, and infected individuals shed high loads of virus. Transmission occurs primarily through the faecal-oral route, either by consumption of contaminated food or water, or by spreading directly from person to person. Among foods, bivalve shellfish and vegetables are readily vectors due to their mode of consumption raw or slightly cooked. NoV survive for long time on different surfaces and thus, environment may serve as a source of new infections. Therefore, disinfection treatmens of water or foods may help in the prevention of NoV outbreaks. In fact, prevention is currently the key for their control, since no effective treatments or vaccines are available.

All these data are indicative of the importance of noroviruses as human pathogens worldwide, and of the necessity of efforts to develop effective tools for their control and prevention. The purpose of this volume, which presents a compilation of the latest research on these aspects, is to gather together information to help further understand on the prevalence and distribution of genotypes and strains, the potential emergence of new strains of the pathogen, as well as on strategies for the prevention and treatment of Norovirus infections.