Decoding Norovirus Biology: Insights into Epidemiology, Structural Dynamics, Host Interactions, and Viral Replication

Norovirus is the leading cause of acute infectious gastroenteritis in the world and accounts for a significant proportion of outbreaks at the food-borne and person-to-person levels. Due to their low infectious dose, persistence in the environment, and broad genetic diversity, they can quickly spread and reappear in even the most diverse populations. This review integrates current knowledge on the epidemiology of noroviruses, genomic organization, structural biology, virus–host interactions, and replication mechanisms, with a focus on factors that determine virus evolution and strain dominance. Literature has been systematically searched in the PubMed and Scopus databases to incorporate recent experimental and epidemiological findings. Analysis of global surveillance data indicates ongoing genetic diversification of circulating strains, with periodic replacement of major variants, particularly the GII.4 lineage. Variability of the capsid and recognition of histo-blood Group Antigens strongly affects the host’s susceptibility, viral attachment and immune escape. The capsid consists of most of the viral protein complexes. The structural proteins VP1 and VP2 are responsible for determining the contours of the capsid and antigenic specificity. Non-structural proteins are responsible for coordinating the genome replication and the modification of host cell pathways to favor the production of the virus. Eliminating these gaps by means of integrated genomic surveillance and functional studies will provide insight into the evolution of norovirus and help to develop broadly effective vaccines and antiviral strategies.