The virus that does not cause chronic liver disease Hepatitis A The virus that does not cause chronic liver disease

Hepatitis A “Infectious Hepatitis” First characterized in 1973 Detected in human feces Hepatovirus genus A reportable infectious disease U.S. rate of infection 4/100,000 Highest among children

Risk Factors Sexual or household contact International travel Men who have sex w/ men (MSM) Intravenous drug abuse (IVDA) Daycare

Transmission Unwitting contact w/ infected person Most cases unknown Primary route is fecal oral either by person to person contact or ingestion of contaminated food or water

Pathogenesis After ingestion, the HAV survives gastric acid, moves to the small intestine and reaches the liver via the portal vein Replicates in hepatocyte cytoplasm Not a cytopathic virus Immune mediated cell damage more likely Once mature the HAV travels through sinusoids and enters bile canaliculi, released into the small intestine and systemic circulation, excreted in feces

Clinical Features Incubation is usually 2 to 4 weeks, rarely 6 weeks Complete recovery within 2 months for > 50% Within 6 months for almost all others

Clinical Features Low mortality in healthy people High morbidity High mortality when older than age 60 High in presence of chronic liver disease High morbidity Around 20% need hospitalization Lost work days Most become jaundiced

Clinical Features Asymptomatic < 2 year old Symptomatic – 5 and older ill about 8 weeks Cholestatic – jaundice lasts > 10 weeks Relapsing w/ 2 or more bouts acute HAV over a 6 to 10 week period Acute liver failure – rare in young. When it occurs, is rapid i.e., within 4 weeks

Signs and Symptoms Prodrome lasts 1-2 weeks: fatigue, asthenia, anorexia, nausea, vomiting, and abdominal pain Less common: fever, cephalgia, arthralgia, myalgia, and diarrhea Dark urine is followed by jaundice and hepatomegaly Less common: splenomegaly, cervical lymphadenopathy

Diagnosis During acute infection, anti HAV IgM appears first HAV IgG antibody appears early in the course of infection and remains detectable for life, providing lifelong immunity

Prevention Immunization All children 12 – 24 months Travelers, occupational exposure risk All patients w/ hepatitis B or C or those awaiting liver transplantation HIV positive patients MSM IVD users

Immunize People w/ clotting factor deficiencies Lab workers handling live hepatitis A vaccine Need for post exposure prophylaxis uncommon. Administration of the vaccine is effective. If needed, administer immune serum globulin within 2 weeks 0.02 ml/Kg IM

Hepatitis A Vaccine The vaccine is inactivated HAV Schedule for 2 – 18 years depends upon the manufacturer: Havirx: 720 EL U/.5mL @ 0, 6-12 mo Vaqta: 25 U.5mL @ 0, 6-18 mo

Hepatitis A Vaccine For those over age 18: Havirx: 1440 EL U/1mL @ 0, 6-12 mo Vaqta: 50 U/1mL @ 0, 6-18 mo Adverse effects: rarely anaphylaxis, injection site induration, erythema, edema, fatigue, mild fever, malaise, anorexia, nausea Twinrix: 720 El U/1mL 0, 1, 6 mo plus 20 mcg HBV