Insights into the Biology of Norovirus: The So-Called “Perfect” Human Pathogen

Noroviruses (NoVs), members of the Family Caliciviridae, are the leading cause of nonbacterial gastroenteritis outbreaks across all age groups worldwide. NoVs also play a major role in sporadic gastroenteritis, being regarded as the most common cause in adults, and second only to rotavirus, among children. Indeed, in countries implementing routine rotavirus vaccination, NoVs are increasingly being identified as the primary cause of viral gastroenteritis among children. The success of NoV as a human pathogen may be attributed to several factors such as its highly transmissible and contagious nature, moderate virulence, rapid and constant evolution resulting in genetic diversity, and induction of limited protective immunity. This chapter aims to provide insights into different aspects of NoV biology with a focus on the viral life cycle, immunopathogenesis, viral evolution, and genetic diversity. Further, the review discusses NoV epidemiology and disease burden, clinical features of NoV infections, as well as current strategies and challenges for diagnosis, prevention, and control of this so-called “perfect” human pathogen.