What are the likely causes of hepatitis in a patient with a recent travel history to a foreign location, considering their vaccination history and potential high-risk behaviors?

Causes of Hepatitis After Travel

Hepatitis A is the most likely cause of hepatitis in a returned traveler, accounting for the majority of travel-associated viral hepatitis cases and occurring 100 times more frequently than typhoid fever in travelers to developing countries. 1, 2

Primary Etiologies by Transmission Route

Fecal-Oral Transmission (Most Common)

Hepatitis A virus (HAV) is transmitted through contaminated water, food (especially shellfish), or direct contact and represents the most common vaccine-preventable disease acquired during international travel. 1, 2, 3

• Risk is 4-30 cases per 100,000 months of stay in endemic areas for unvaccinated travelers 1
• Approximately 75% of travel-related cases are associated with travel to Mexico, Central America, or South America 1
• Risk persists even among travelers staying in luxury hotels or urban areas who report observing protective measures 1
• Incubation period averages 28 days (range: 15-50 days), so symptoms may appear weeks after return 1

Hepatitis E virus (HEV) is also transmitted fecal-orally and is the most common cause of viral hepatitis in Asia. 1, 4

• More common in travelers returning from South and Southeast Asia 1
• Can cause fulminant hepatitis, particularly in pregnant women 1
• Chronic infection can occur in immunocompromised patients 1

Bloodborne/Sexual Transmission

Hepatitis B virus (HBV) is predominantly transmitted through sexual contact or blood exposure in travelers. 1

• Risk is approximately 10 times lower than hepatitis A in travelers 2
• Consider in travelers with unprotected sexual contact, medical/dental procedures abroad, or tattoo/piercing exposure 5
• Incubation period is longer (45-180 days), so may present months after return 4

Hepatitis C virus (HCV) should be considered with similar exposures to HBV. 4

Clinical Presentation Clues

The clinical syndrome typically includes: 1, 3

• Dark urine (bilirubinuria) - usually the first symptom prompting medical attention 1, 6
• Followed within days by jaundice, clay-colored stools, and tender hepatomegaly 1
• Preceded by 1-7 day prodrome of fever, malaise, anorexia, nausea, and vomiting 1, 3
• Symptoms more likely to be clinically apparent in adults (>70% develop jaundice) versus children <6 years (>90% asymptomatic) 1, 6

Risk Stratification by Travel History

High-Risk Exposures to Investigate:

Food and water exposures: 1, 7

• Raw or undercooked shellfish (HAV can remain stable in contaminated shellfish beds for months) 7
• Untreated water or ice 5
• Food from street vendors or establishments with poor sanitation 1

Sexual and blood exposures: 1, 5

• Unprotected sexual contact with new partners (HBV risk) 5
• Medical or dental procedures abroad 5
• Tattoos, piercings, or injection drug use 1

Specific populations at higher risk: 1

• Immigrants or children visiting friends/relatives in countries of origin (often unvaccinated and engage in higher-risk behaviors) 1
• Men who have sex with men (MSM) - cyclic HAV outbreaks occur 1
• Persons who use injection or non-injection drugs 1

Diagnostic Approach

Order IgM anti-HAV as the first-line test - this confirms acute hepatitis A infection and is the most likely diagnosis in a returned traveler. 6, 3

If IgM anti-HAV is negative, proceed with: 4, 3

• HBsAg and anti-HBc IgM for acute hepatitis B
• Anti-HCV antibody with HCV RNA if positive
• Anti-HEV IgM if travel to endemic areas (Asia)
• Consider other viral causes (EBV, CMV, HSV) if above are negative 4

Critical Pitfalls to Avoid

• Do not assume vaccination status protects - verify actual vaccination records, as many travelers (especially those visiting friends/relatives) remain unvaccinated despite recommendations 1
• Do not dismiss luxury travel as low-risk - HAV transmission occurs even in upscale accommodations 1
• Remember the patient was most infectious 14-21 days BEFORE symptom onset - contact tracing and household prophylaxis may be needed 1, 6
• Consider chronic liver disease as a risk factor for severe outcomes - patients with underlying liver disease who acquire HAV are at increased risk for fulminant hepatitis 7