Microbiology · 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
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 →
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.
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.
Related
Related conditions
← Back to the group: 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 (World Health Organization (WHO), 2025); Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions (CDC, 2024).
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Representative model, for educational purposes only.