Hepatitis A Infection

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Hepatitis A Infection

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Hepatitis A Infection

  1. 1. HEPATITIS A INFECTION Dr.T.V.Rao MDDR.T.V.RAO MD 1
  2. 2. WHAT IS HEPATITIS?• Hepatitis means inflammation of the liver • Hepat (liver) + itis (inflammation)= Hepatitis• Viral hepatitis means there is a specific virus that is causing your liver to inflame (swell or become larger than normal)DR.T.V.RAO MD 2
  3. 3. HEPATITIS INFLAMMATION OF THE LIVER• Can have many causes • drugs • toxins • alcohol • viral infections (A, B, C, D, E) • other infections (parasites, bacteria) • physical damageDR.T.V.RAO MD 3
  4. 4. VIRAL HEPATITIS5 types:A : fecal-oral transmissionB : sexual fluids & blood to bloodC : blood to blood VaccineD : travels with B PreventableE: fecal–oral transmissionAdapted from Corneil, 2003 DR.T.V.RAO MD 4
  5. 5. HEPATITIS A • Epidemic jaundice described by Hippocrates • Differentiated from hepatitis B in 1940s • Serologic tests developed in 1970s • Most commonly reported type of hepatitis in the United StatesDR.T.V.RAO MD 5
  6. 6. Viral Hepatitis - Historical Perspectives “Infectious” A E Enterically transmittedViral hepatitis NANB Parenterall “Serum” B D C y transmitted F, G, TTV ? other DR.T.V.RAO MD 6
  7. 7. Viral Hepatitis - Overview Type of hepatitis A B C D ESource of feces blood/ blood/ blood/ fecesvirus blood-derived blood-derived blood-derived body fluids body fluids body fluidsRoute of fecal-oral percutaneous percutaneous percutaneous fecal-oraltransmission permucosal permucosal permucosalChronic no yes yes yes noinfectionPrevention pre/post- pre/post- blood donor pre/post- ensure safe exposure exposure screening; exposure drinking immunization immunization risk behavior immunization; water modification risk behavior DR.T.V.RAO MD modification 7
  8. 8. HEPATITIS A VIRUS • Naked RNA virus • Related to enteroviruses, formerly known as enterovirus 72, now put in its own family: heptovirus • One stable serotype only • Difficult to grow in cell culture: primary marmoset cell culture and also in vivo in chimpanzees and marmosets • 4 genotypes exist, but in practice most of them are group 1DR.T.V.RAO MD 8
  9. 9. HEPATITIS A VIRUS• Picornavirus (RNA)• Humans are only natural host• Stable at low pH• Inactivated by high temperature, formali n, chlorineDR.T.V.RAO MD 9
  10. 10. Geographic Distribution of HAV InfectionAnti-HAV Prevalence High Intermediate Low Very Low DR.T.V.RAO MD 10
  11. 11. DENSITY OF HEPATITIS A INFECTIONDR.T.V.RAO MD 11
  12. 12. Hepatitis A - Clinical Features  Incubation period: Average 30 days Range 15-50 days  Jaundice by <6 yrs, <10% age group: 6-14 yrs, 40%-50% >14 yrs, 70%-80%  Complications: Fulminant hepatitis Cholestatichepatitis Relapsing hepatitis  Chronic sequelae: NoneDR.T.V.RAO MD 12
  13. 13. SIGNS AND SYMPTOMS• A few may have specific liver related symptoms initially: • Pale stool (poo) • Jaundice (yellowing of the skin or eyes) DR.T.V.RAO MD 13
  14. 14. Hepatitis A Virus Transmission • Close personal contact (e.g., household contact, sex contact, child day care centers) • Contaminated food, water (e.g., infected food handlers, raw shellfish) • Blood exposure (rare) (e.g., injecting drug use, transfusion)DR.T.V.RAO MD 14
  15. 15. 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 fecesDR.T.V.RAO MD 15
  16. 16. HEPATITIS A • Symptoms • Nausea • Dark urine • Loss of appetite • Pale stool • Vomiting • Jaundice • Fatigue • Stomach pain • Fever • Side pain A person may have all, some or none of theseDR.T.V.RAO MD 16
  17. 17. HEPATITIS A CLINICAL FEATURES • Incubation period 28 days (range 15-50 days) • Illness not specific for hepatitis A • Likelihood of symptomatic illness directly related to age • Children generally asymptomatic, adults symptomaticDR.T.V.RAO MD 17
  18. 18. CLINICAL FEATURES• Asymptomatic < 2 year old• Symptomatic – 5 and older ill about 8 weeks• Cholestasis – 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 weeksDR.T.V.RAO MD 18
  19. 19. CLINICAL FEATURES• Asymptomatic < 2 year old• Symptomatic – 5 and older ill about 8 weeks• Cholestasis – 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 weeksDR.T.V.RAO MD 19
  20. 20. LABORATORY DIAGNOSIS• Acute infection is diagnosed by the detection of HAV-IgM in serum by EIA.• Past Infection i.e. immunity is determined by the detection of HAV-IgG by EIA.• Cell culture – difficult and take up to 4 weeks, not routinely performed• Direct Detection – EM, RT-PCR of faeces. Can detect illness earlier than serology but rarely performed. DR.T.V.RAO MD 20
  21. 21. Hepatitis A Vaccination Strategies Epidemiologic Considerations• Many cases occur in community-wide outbreaks • no risk factor identified for most cases • highest attack rates in 5-14 year olds • children serve as reservoir of infection• Persons at increased risk of infection • travelers • homosexual men • injecting drug users DR.T.V.RAO MD 21
  22. 22. 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 usersDR.T.V.RAO MD 22
  23. 23. 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 IMDR.T.V.RAO MD 23
  24. 24. HEPATITIS A VACCINES• Inactivated whole virus• HAVRIX (GlaxoSmithKline)• VAQTA (Merck Vaccine Division)• Pediatric and adult formulations• Licensed for persons >2 yearsDR.T.V.RAO MD 24
  25. 25. HEPATITIS A VACCINE IMMUNOGENICITY Adults• 95% seropositive after one dose• 100% seropositive after two doses• >97% seropositive after one• 100% seropositive after 2 doses Children (>2 years) and AdolescentsDR.T.V.RAO MD 25
  26. 26. • Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in Developing World • Email • doctortvrao@gmail.comDR.T.V.RAO MD 26

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