Viral gastroenteritis: norovirus, rotavirus, adenovirus and SARS-CoV-2
- Lesion
Viruses kill the absorbing cells at the tips of the villi, causing short bouts of vomiting and watery diarrhoea.
What it is
Viruses are the commonest cause of acute diarrhoea. They infect mature enterocytes of the small intestine; the villi are repopulated by immature cells that absorb poorly and secrete, so diarrhoea is part secretory and part osmotic. Biopsies are rarely taken and show nonspecific changes. Norovirus now leads overall where rotavirus vaccines are used; rotavirus remains a major cause of child deaths in poorer regions.
Structure
- Mild villous shortening and crypt hyperplasia.
- Increased intraepithelial and lamina propria lymphocytes; some neutrophils.
- Epithelial vacuolization and a damaged brush border with reduced enzymes.
Step by step
- The virus infects mature absorptive enterocytes near the villus tips.
- Infected cells die and are replaced by immature crypt-type cells.
- Absorption of sodium and nutrients falls while secretion continues.
- Unabsorbed sugars add an osmotic component (temporary lactose intolerance).
- Vomiting and watery diarrhoea last a few days until mature cells return.
Clinical notes
- Dehydration is the danger, especially in infants and the elderly; oral rehydration is the mainstay.
- Rotavirus vaccination is in the Colombian national schedule; rotavirus infection and vaccination have been linked to intussusception through lymphoid hyperplasia.
Test yourself
Think of the answer, then tap the question to see it.
Which cells do enteric viruses such as rotavirus destroy?
Mature absorptive enterocytes at the villus tips, which are replaced by immature secretory cells.
Why are some people resistant to norovirus?
They lack functional FUT2, so their mucosal cells do not display the blood-group glycans that the virus binds.
Which age group is most affected by severe rotavirus diarrhoea?
Children between about six and twenty-four months.
Connections
Microorganisms4
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Viral Gastroenteritis (StatPearls (NCBI Bookshelf), 2025); About Norovirus (Centers for Disease Control and Prevention, 2024); About Rotavirus (Centers for Disease Control and Prevention, 2024).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.