Hepatitis A Infection
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Transcript of Hepatitis A Infection
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
DR.T.V.RAO MD 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 States
DR.T.V.RAO MD 6
A“Infectious”
“Serum”
Viral hepatitis
Entericallytransmitted
ParenterallytransmittedF, G, TTV
? other
E
NANB
B D C
Viral Hepatitis - Historical Perspectives
DR.T.V.RAO MD 7
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
DR.T.V.RAO MD 10
Geographic Distribution of HAV Infection
Geographic Distribution of HAV Infection
Anti-HAV Prevalence
High
Intermediate
Low
Very Low
DR.T.V.RAO MD 11
DENSITY OF HEPATITIS A INFECTION
DR.T.V.RAO MD 12
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
DR.T.V.RAO MD 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 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
DR.T.V.RAO MD 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 feces
DR.T.V.RAO MD 16
• 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
DR.T.V.RAO MD 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 weeks
DR.T.V.RAO MD 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.
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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
DR.T.V.RAO MD 24
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• [email protected]