Overview
Acute viral liver infection transmitted through contaminated food and water. The most common vaccine-preventable travel disease worldwide.
Symptoms
Symptoms | Frequency | Severity | Onset |
|---|---|---|---|
| Abdominal pain | 60% | Moderate | Early |
| Fatigue | 80% | Moderate | Early |
| Fever | 70% | Mild | Early |
| Loss of appetite | 80% | Mild | Early |
| Malaise | 75% | Mild | Early |
| Nausea | 70% | Moderate | Early |
| Headache | 50% | Mild | Early |
| Myalgia | 50% | Mild | Early |
| Vomiting | 40% | Mild | Early |
| Dark urine | 80% | Moderate | Peak |
| Hepatomegaly | 60% | Moderate | Peak |
| Jaundice | 70% | Severe | Peak |
| Itching | 40% | Mild | Peak |
| Weight loss | 30% | Mild | Peak |
| Arthralgia | 15% | Mild | Peak |
| Splenomegaly | 15% | Mild | Peak |
| Rash | 5% | Mild | Peak |
| Diarrhea | 20% | Mild | Any phase |
Transmission
Overview
Highly contagious liver infection caused by the hepatitis A virus.
Overview
Hepatitis A is caused by the Hepatitis A virus (HAV), a non-enveloped RNA virus of the family Picornaviridae. Transmission occurs via the fecal-oral route — through ingestion of contaminated water or food (especially raw shellfish, unpeeled fruits, salads), direct person-to-person contact, or rarely through blood. The virus is highly stable in the environment, surviving weeks on surfaces and resistant to freezing. Unlike hepatitis B and C, hepatitis A does not cause chronic infection; recovery confers lifelong immunity.
Emergency Signs
Seek emergency medical care immediately if:
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Persistent vomiting with inability to keep fluids down
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Severe abdominal pain (especially right upper quadrant)
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Signs of liver failure: confusion, drowsiness, personality changes (hepatic encephalopathy)
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Bruising or bleeding easily (coagulopathy)
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Very dark urine with pale stools and worsening jaundice after initial improvement
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Fever returning after jaundice has appeared
Detailed Symptoms
Most common signs and symptoms
Incubation period: 15–50 days (average 28–30 days). Clinical presentation varies with age:
Children <6 years: Usually asymptomatic (>70% of cases) or mild non-specific illness without jaundice.
Older children and adults — prodromal phase (5–7 days):
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Abrupt onset of fatigue, malaise, and anorexia
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Nausea, vomiting, and abdominal discomfort (right upper quadrant)
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Low-grade fever (38–39°C)
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Myalgia and arthralgia
Icteric phase (2–6 weeks):
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Jaundice (scleral icterus progressing to skin yellowing)
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Dark urine (cola-colored) — often the first sign noticed
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Pale/clay-colored stools (acholic)
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Hepatomegaly with tenderness
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Pruritus (itching) in some patients
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Paradoxical improvement — fever and GI symptoms often resolve as jaundice appears
Recovery phase: Gradual resolution over weeks to months. Fatigue may persist for several months.
Knowing the symptoms is the first step to a quick response.
Course of Disease
Hepatitis A typically resolves within 2-6 months. Rarely, it can cause acute liver failure.
Diagnosis
How this disease is identified
Laboratory confirmation:
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Anti-HAV IgM: Positive at symptom onset, detectable for 3–6 months — confirms acute infection
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Anti-HAV IgG: Appears during convalescence, persists lifelong — indicates past infection or vaccination
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Liver function tests: ALT/AST markedly elevated (often >1,000 IU/L), bilirubin elevated in icteric cases
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HAV RNA (RT-PCR): Available in reference labs; useful for outbreak investigation and genotyping
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Stool HAV detection: Virus shed in stool 1–2 weeks before symptoms through ~1 week after jaundice onset
Differential diagnosis: hepatitis B, C, E; EBV; CMV; leptospirosis; drug-induced liver injury.
Treatment
Available treatment methods
No specific antiviral therapy exists. Management is supportive:
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Rest and hydration: Avoid strenuous activity during acute phase
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Nutrition: Small, frequent meals
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avoid alcohol for ≥6 months after illness (hepatotoxicity risk)
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Symptom relief: Antiemetics for nausea
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cholestyramine for pruritus
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avoid hepatotoxic medications (paracetamol limited to <2 g/day)
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Monitoring: Serial liver function tests in severe cases
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Hospitalization criteria: Persistent vomiting, INR >1.5, encephalopathy signs, inability to maintain hydration
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Fulminant hepatitis (<1% of cases): Requires ICU care
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liver transplantation may be needed
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Most patients recover completely within 2–6 months with no residual liver damage.
Most cases are effectively treated with early diagnosis.
Prevention Details
How to protect yourself
Vaccination (primary prevention):
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Inactivated HAV vaccine: 2-dose schedule — dose 1 provides ~95% protection within 2–4 weeks; dose 2 at 6–12 months for long-term immunity (estimated 25–40+ years, possibly lifelong)
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Combined HAV/HBV vaccine (Twinrix): 3-dose schedule (0, 1, 6 months) or accelerated (0, 7, 21 days + 12-month booster)
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Pre-travel: Vaccinate ≥2 weeks before departure; single dose protects most travelers
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Post-exposure prophylaxis: HAV vaccine within 2 weeks of exposure (for healthy persons 1–40 years); immunoglobulin for <12 months, >40 years, immunocompromised, or chronic liver disease patients
Food and water hygiene:
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Drink only bottled or boiled water; avoid ice
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Eat thoroughly cooked food; peel fruits yourself
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Avoid raw shellfish (filter-feeding shellfish concentrate HAV)
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Strict hand hygiene with soap after toilet use and before eating
Preparation is the best protection.
Travel Advice
Risk to travelers:
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High risk: All destinations in Africa, Asia (except Japan), Central and South America, Eastern Europe, the Middle East
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Hepatitis A is the #1 vaccine-preventable travel infection — vaccinate before ALL travel to endemic regions, regardless of trip duration or accommodation standard
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Luxury resorts and business hotels are NOT protective — HAV outbreaks have occurred in 4-5 star hotels
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Single dose provides rapid protection (2 weeks); schedule dose 2 upon return for long-term immunity
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Combined HAV/HBV vaccine (Twinrix) is efficient for frequent travelers
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Practice strict food and water hygiene even when vaccinated (vaccine is ~95%, not 100% effective)
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Travelers with chronic liver disease should be prioritized for vaccination — hepatitis A superinfection carries high mortality
How common is it?
Statistics and geographic data
Hepatitis A is the most common vaccine-preventable infection in travelers. WHO estimates ~159 million new infections annually (2019 data), with ~39,000 deaths. Prevalence correlates inversely with sanitation:
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High endemicity: Sub-Saharan Africa, South Asia, Central America — nearly universal childhood infection; most adults immune
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Intermediate: Eastern Europe, Middle East, Latin America — shifting epidemiology with rising adult susceptibility
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Low endemicity: Western Europe, North America, Japan, Australia — susceptible adult populations at risk when traveling
Outbreaks occur via contaminated water supplies, food handlers, MSM populations, PWID, and institutional settings. Seroprevalence in returning travelers with acute hepatitis: HAV is the cause in ~40% of cases (GeoSentinel data). Attack rate among unvaccinated travelers to endemic areas: 3–20 per 1,000 person-months of travel.
Risk Factors
Who is most at risk
Traveling to endemic areas, consuming contaminated food or water, poor hygiene practices.
Complications Details
Potential complications
Hepatitis A is generally self-limiting, but complications increase with age and pre-existing liver disease:
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Prolonged/relapsing hepatitis: 10–15% of cases
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symptoms relapse 1–3 months after initial resolution, may last up to 6 months
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Cholestatic hepatitis: Prolonged jaundice (>3 months) with intense pruritus
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excellent prognosis
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Fulminant hepatic failure: <1% overall (higher in patients >50 years and those with chronic hepatitis B or C)
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mortality 50–70% without transplantation
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Autoimmune hepatitis trigger: HAV may trigger autoimmune hepatitis in genetically predisposed individuals
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Extrahepatic manifestations (rare): Vasculitis, arthritis, cryoglobulinemia, acute kidney injury, aplastic anemia, pancreatitis
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Case fatality rate: 0.1% in children <15 years
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0.3% in adults 15–39
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2.1% in adults ≥40 (WHO data)
Recovery & Outlook
Expected outcomes and recovery
Prognosis is excellent with supportive care. Most people recover completely within 2-6 months.
