DR.T.V.RAO MD 1

Dr.T.V.Rao MD

HEPATITIS A INFECTION

DR.T.V.RAO MD 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 3

HEPATITISINFLAMMATION OF THE LIVER

• Can have many causes• drugs• toxins• alcohol• viral infections (A, B, C, D, E)• other infections (parasites, bacteria)

• physical damage

DR.T.V.RAO MD 4

VIRAL HEPATITIS5 types:

A: fecal-oral transmission

B: sexual fluids & blood to blood

C: blood to blood

D: travels with B

E: fecal–oral transmission

VaccinePreventable

Adapted from Corneil, 2003

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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 States

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A“Infectious”

“Serum”

Viral hepatitis

Entericallytransmitted

ParenterallytransmittedF, G, TTV

? other

E

NANB

B D C

Viral Hepatitis - Historical Perspectives

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Viral Hepatitis - OverviewViral Hepatitis - Overview

AA BB CC DD EESource ofvirus

feces blood/blood-derived

body fluids

blood/blood-derived

body fluids

blood/blood-derived

body fluids

feces

Route oftransmission

fecal-oral percutaneouspermucosal

percutaneouspermucosal

percutaneouspermucosal

fecal-oral

Chronicinfection

no yes yes yes no

Prevention pre/post-exposure

immunization

pre/post-exposure

immunization

blood donorscreening;

risk behaviormodification

pre/post-exposure

immunization;risk behaviormodification

ensure safedrinkingwater

Type of hepatitis

DR.T.V.RAO MD 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 1

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• Picornavirus (RNA)• Humans are only

natural host• Stable at low pH• Inactivated by high

temperature, formalin, chlorine

HEPATITIS A VIRUS

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Geographic Distribution of HAV Infection

Geographic Distribution of HAV Infection

Anti-HAV Prevalence

High

Intermediate

Low

Very Low

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DENSITY OF HEPATITIS A INFECTION

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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

CholestatichepatitisRelapsing

hepatitis Chronic sequelae: None

Hepatitis A - Clinical Features

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SIGNS AND SYMPTOMS• A few may have specific liver related symptoms initially:

• Pale stool (poo)

• Jaundice (yellowing of the skin or eyes)

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• 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

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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

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• Nausea

• Loss of appetite

• Vomiting

• Fatigue

• Fever

• Dark urine

• Pale stool

• Jaundice

• Stomach pain

• Side pain

HEPATITIS A

A person may have all, some or none of these

• Symptoms

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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

symptomatic

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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 weeks

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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 weeks

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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.

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• 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

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PREVENTIONIMMUNIZATION

• 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

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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

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HEPATITIS A VACCINES• Inactivated whole virus• HAVRIX (GlaxoSmithKline)• VAQTA (Merck Vaccine Division)• Pediatric and adult formulations• Licensed for persons >2 years

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HEPATITIS A VACCINEIMMUNOGENICITY

• 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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• Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in

Developing World

• Email• doctortvrao@gmail.com