[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/) › Hepatitis A virus

[Microbiology](https://durgical.com/en/microbiology/) · [RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/)

# Hepatitis A virus

- Virus
- Non-enveloped (naked)
- Contact
- Exam priority: high

A virus spread through water or food contaminated with stool. It causes acute hepatitis that almost always clears on its own and never becomes chronic.

Updated 2026-11-01

Also called: HAV

## Key points

- Non-enveloped picornavirus spread faecal-orally
- Never causes chronic hepatitis
- Anti-HAV IgM = acute infection; IgG = immunity
- The virus is shed in stool before jaundice appears

## At a glance

**Shape**
Icosahedral

**Genome**
Single-stranded, positive-sense RNA

**Envelope**
Non-enveloped (naked)

**Family**
Picornaviridae, genus Hepatovirus

**Size**
About 27 to 30 nm

## Morphology

- Naked capsid, highly resistant to acid, moderate heat and the environment
- A single serotype

## Transmission

- Faecal-oral: contaminated water or food (raw shellfish, poorly washed vegetables)
- Close contact, including oral-anal sex
- Outbreaks in day-care centres, institutions and areas without sanitation

**Reservoir:** Humans

### Isolation precautions

What the care team adds to standard precautions.

**Contact**
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.

## Virulence factors

- Replicates in hepatocytes without directly destroying them: cytotoxic T cells cause the injury
- Shed through bile into stool, reaching high titres before jaundice

## Diseases it causes

- Acute hepatitis A, sometimes cholestatic or relapsing; rarely fulminant [Viral hepatitis →](https://durgical.com/en/conditions/viral-hepatitis/)

## Clinical picture

- Incubation 2 to 6 weeks
- Young children are often asymptomatic or anicteric
- Adults: fever, malaise, nausea, right upper quadrant pain, dark urine, jaundice
- Severity and death rise with age; rarely fulminant hepatitis

## Diagnosis

- Anti-HAV IgM: confirms acute infection
- Anti-HAV IgG: past infection or vaccination (immunity)
- Markedly raised transaminases
- RT-PCR in specialized laboratories

## Treatment

There is no antiviral: care is supportive. Alcohol and liver-toxic drugs are avoided; fulminant liver failure is referred to a transplant centre.

Drug class only; doses and regimens are set by the clinician from the current guideline.

## Prevention

- Safe water, basic sanitation and handwashing
- Inactivated vaccine
- Post-exposure prophylaxis with vaccine or immunoglobulin depending on age and risk

**Vaccine:** Inactivated vaccine; Colombia includes it in the PAI as a single dose at one year of age.

## In Colombia

Hepatitis A is endemic in Colombia and notifiable to SIVIGILA; outbreaks are linked to unsafe water and, in recent years, also to sexual spread among young adults.

## Memory aid

A is for "Acute" and "Alimentary": it comes in by mouth and leaves without staying.

## Test yourself

Think of the answer, then tap the question to see it.

## Which serological marker confirms acute hepatitis A?

Anti-HAV IgM.

## Can hepatitis A become chronic?

No. Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease.

## Why is a child with hepatitis A so contagious to the family?

The child sheds large amounts of virus in stool, even before jaundice and even without symptoms.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/hepatitis-a-virus/)

## Related

- [Hepatitis E virus](https://durgical.com/en/microbiology/hepatitis-e-virus/)

## Related conditions

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

**Contact**
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.

**Droplet**
Surgical mask within about a metre; single room.

**Airborne**
N95 respirator and a negative-pressure room.

[← Back to the group: RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Hepatitis A](https://www.who.int/news-room/fact-sheets/detail/hepatitis-a) (World Health Organization (WHO), 2025); [Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions](https://www.cdc.gov/infection-control/hcp/isolation-precautions/appendix-a-type-duration.html) (CDC, 2024).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/hepatitis-a-virus/