Hepatitis A Infection

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Hepatitis A Infection

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HEPATITIS A INFECTION:

Dr.T.V.Rao MD 1 Dr.T.V.Rao MD HEPATITIS A INFECTION

What Is Hepatitis?:

What Is Hepatitis? Dr.T.V.Rao MD 2 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)

Hepatitis inflammation of the liver:

Hepatitis inflammation of the liver Dr.T.V.Rao MD 3 Can have many causes drugs toxins alcohol viral infections (A, B, C, D, E) other infections (parasites, bacteria) physical damage

Viral Hepatitis:

Viral Hepatitis Dr.T.V.Rao MD 4 5 types: A : fecal-oral transmission B : sexual fluids & blood to blood C : blood to blood D : travels with B E : fecal–oral transmission Vaccine Preventable Adapted from Corneil, 2003

Hepatitis A:

Hepatitis A Dr.T.V.Rao MD 5 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 States

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A “ Infectious” “ Serum” Viral hepatitis Enterically transmitted Parenterally transmitted F, G, TTV ? other E NANB B D C Viral Hepatitis - Historical Perspectives Dr.T.V.Rao MD 6

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Dr.T.V.Rao MD 7 Viral Hepatitis - Overview A B C D E Source of virus feces blood/ blood-derived body fluids blood/ blood-derived body fluids blood/ blood-derived body fluids feces Route of transmission fecal-oral percutaneous permucosal percutaneous permucosal percutaneous permucosal fecal-oral Chronic infection no yes yes yes no Prevention pre/post- exposure immunization pre/post- exposure immunization blood donor screening; risk behavior modification pre/post- exposure immunization; risk behavior modification ensure safe drinking water Type of hepatitis

Hepatitis A Virus:

Hepatitis A Virus Dr.T.V.Rao MD 8 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 1

Hepatitis A Virus:

Picornavirus (RNA) Humans are only natural host Stable at low pH Inactivated by high temperature, formalin, chlorine Hepatitis A Virus Dr.T.V.Rao MD 9

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Geographic Distribution of HAV Infection Anti-HAV Prevalence High Intermediate Low Very Low Dr.T.V.Rao MD 10

Density of Hepatitis A Infection:

Density of Hepatitis A Infection Dr.T.V.Rao MD 11

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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: None Hepatitis A - Clinical Features Dr.T.V.Rao MD 12

Signs and Symptoms:

Signs and Symptoms Dr.T.V.Rao MD 13 A few may have specific liver related symptoms initially: Pale stool (poo) Jaundice (yellowing of the skin or eyes)

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Dr.T.V.Rao MD 14 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) Hepatitis A Virus Transmission

Pathogenesis:

Pathogenesis Dr.T.V.Rao MD 15 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

Hepatitis A:

Nausea Loss of appetite Vomiting Fatigue Fever Dark urine Pale stool Jaundice Stomach pain Side pain Hepatitis A Dr.T.V.Rao MD 16 A person may have all, some or none of these Symptoms

Hepatitis A Clinical Features:

Hepatitis A Clinical Features Dr.T.V.Rao MD 17 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 symptomatic

Clinical Features:

Clinical Features Dr.T.V.Rao MD 18 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 weeks

Clinical Features:

Clinical Features Dr.T.V.Rao MD 19 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 weeks

Laboratory Diagnosis:

Laboratory Diagnosis Dr.T.V.Rao MD 20 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.

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Dr.T.V.Rao MD 21 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 Hepatitis A Vaccination Strategies Epidemiologic Considerations

Prevention Immunization :

Prevention Immunization Dr.T.V.Rao MD 22 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:

Immunize Dr.T.V.Rao MD 23 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 Vaccines:

Hepatitis A Vaccines Dr.T.V.Rao MD 24 Inactivated whole virus HAVRIX (GlaxoSmithKline) VAQTA (Merck Vaccine Division) Pediatric and adult formulations Licensed for persons > 2 years

Hepatitis A Vaccine Immunogenicity:

Hepatitis A Vaccine Immunogenicity Dr.T.V.Rao MD 25 95% seropositive after one dose 100% seropositive after two doses >97% seropositive after one 100% seropositive after 2 doses Adults Children ( > 2 years) and Adolescents

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Dr.T.V.Rao MD 26 Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in Developing World Email doctortvrao@gmail.com

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