Norovirus Gastroenteritis Outbreaks, Genomic Diversity and Evolution: An Overview

Area of Science:

• Virology
• Public Health
• Epidemiology

Background:

• Norovirus is the leading cause of acute gastroenteritis outbreaks globally, affecting all age groups.
• Discovered in 1972, it belongs to the genus Norovirus within the Caliciviridae family, which is phylogenetically divided into four genera.
• Noroviruses are highly contagious, with infection possible from approximately twenty virus particles.

Purpose of the Study:

• To review the current prevalence and evolution of norovirus strains in developed and developing countries.
• To outline the general characteristics, genomic diversity, classification, and outbreak status of norovirus gastroenteritis.
• To provide a comprehensive understanding for developing prevention and control strategies.

Main Methods:

• Literature review of various studies on norovirus from different countries.
• Analysis of norovirus detection rates in lower-middle-income countries (LMIC) and low-income countries (LIC) from 1997 to 2018.
• Examination of norovirus genomic diversity, classification into genogroups (GI-GX) and genotypes.

Main Results:

• Norovirus detection rates were 14% in LMIC and 8% in LIC between 1997-2018.
• Noroviruses are classified into ten genogroups (GI-GX) with 49 genotypes, with GII being the most prevalent human genogroup.
• Global norovirus prevalence in different age groups (under-5, ≥5, mixed) was similar, ranging from 16% to 19%.

Conclusions:

• Norovirus strains exhibit significant genomic diversity and evolve continuously, with new strains emerging nationally and globally.
• Infection symptoms include diarrhea, vomiting, fever, headache, and stomach pain, with potential complications like dehydration.
• Prevention strategies focus on hand washing and surface disinfection, as no specific treatment exists.