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# 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.

Updated Nov 12, 2026

## Key points

- Norovirus: very low infective dose, outbreaks in schools, hospitals, nursing homes and ships; vomiting and watery diarrhoea for two to three days; chronic infection in transplant patients.
- People lacking FUT2 (non-secretors) resist many norovirus strains.
- Rotavirus: most severe in children of six to twenty-four months; kills mature enterocytes; the NSP4 protein contributes; vaccines are less effective where malnutrition is common.
- Adenovirus: paediatric diarrhoea and illness in immunocompromised adults; villous atrophy, rare inclusions.
- SARS-CoV-2 uses ACE2 and TMPRSS2 on enterocytes; gastrointestinal symptoms are frequent.

## 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.

## Memory aid

Noro spreads on ships; rota strikes toddlers; both strip the villus tips.

## 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.

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## Connections

## Related 3

- [Infectious enterocolitis](https://durgical.com/en/general-pathology/infectious-enterocolitis/)
- [Other enteropathies](https://durgical.com/en/general-pathology/other-enteropathies/)
- [Intestinal obstruction](https://durgical.com/en/general-pathology/intestinal-obstruction/)

## Related conditions 3

- [Acute (viral) gastroenteritis](https://durgical.com/en/conditions/acute-gastroenteritis/)
- [Dehydration in children (acute diarrhoeal disease)](https://durgical.com/en/conditions/dehydration-in-children/)
- [Intussusception (children)](https://durgical.com/en/conditions/intussusception/)

## Microorganisms 4

- [Norovirus](https://durgical.com/en/microbiology/norovirus/)
- [Rotavirus](https://durgical.com/en/microbiology/rotavirus/)
- [Adenovirus](https://durgical.com/en/microbiology/adenovirus/)
- [SARS-CoV-2](https://durgical.com/en/microbiology/sars-cov-2/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

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](https://www.ncbi.nlm.nih.gov/books/NBK518995/) (StatPearls (NCBI Bookshelf), 2025); [About Norovirus](https://www.cdc.gov/norovirus/about/index.html) (Centers for Disease Control and Prevention, 2024); [About Rotavirus](https://www.cdc.gov/rotavirus/about/index.html) (Centers for Disease Control and Prevention, 2024).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/viral-gastroenteritis-norovirus-rotavirus-adenovirus-and-sars-cov-2/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/viral-gastroenteritis-norovirus-rotavirus-adenovirus-and-sars-cov-2/