16/3/20091dr. salwa tayel. 16/3/20092dr. salwa tayel viral hepatitis
TRANSCRIPT
16/3/2009 1Dr. Salwa Tayel
16/3/2009 2Dr. Salwa Tayel
Viral Hepatitis
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Acute Hepatitis – Clinical Symptoms
Asymptomatic > Symptomatic > Fulminant Liver Failure > Death
Symptoms (if present) are the same, regardless of cause (e.g., A, B, C, other viruses, toxins)
• Nausea, vomiting• Abdominal pain• Loss of appetite• Fever• Diarrhea• Light (clay) colored stools• Dark urine• Jaundice (yellowing of eyes, skin)
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Infectious hepatitis, epidemic hepatitis, epidemic jaundice.
• Onset is usually sudden with fever followed within few days
by jaundice.
• Complete recovery is the rule (no chronicity).
• The case-fatality rate among persons of all ages is
approximately 0.3%
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It is worldwide
In developing countries, it occurs in endemic and epidemic forms due to:• Poor environmental sanitation• Overcrowding• Lack of personal hygiene.
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Geographic Distribution of HAV Infection
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Hepatitis A Virus Picornavirus (RNA) Stable at low pH Inactivated by high temperature,
formalin, chlorine
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• Human clinical sub-clinical cases incubating carriers
Through anal orifice with faeces.
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1. Fecal-oral route. Close personal contact; house hold contact, sex contact, day care centers.
2.Common vehicle; contaminated water and food; raw shellfish food handlers .
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Through the mouth.
• Susceptibility is general.
• Post infection immunity after the attack probably lasts for life.
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• Incubation period 28 days (range 15-50 days)
• The maximum infectivity is during the
latter half of the incubation period (2
weeks before and 1 week after onset of
jaundice).
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Agent
Susceptible Host Reservoir
Mode of transmission
Cycle of infection
Portal of ExitPortal of Inlet
IP
PC
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Prevention of Hepatitis A
Vaccination Immune globulin Good hygiene (hand washing) Clean water systems; avoidance of food
contamination Food sanitation especially shell fish and
raw eaten food.
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Pre-exposure– travelers to intermediate and high
HAV-endemic regions
Post-exposure (within 14 days)
Routine– household and other intimate contacts
Selected situations– institutions (e.g., day care centers)– common source exposure (e.g.,
food prepared by infected food handler)
Hepatitis A Prevention – Immune Globulin
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Hepatitis A Vaccine
Inactivated whole virus vaccine.
Schedule 2 doses
First dose then booster dose 6 months after first.
The vaccine should be administered intramuscularly.
Site: deltoid muscle.
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A, B, Cs of Viral Hepatitis
• A – fecal-oral spread: hygiene, drug use, travelers,
day care, food – vaccine-preventable
• B – sexually transmitted – – 100x more infectious than HIV– blood-borne (sex, injection drug use, mother-
child, and health care)– vaccine-preventable
• C – blood borne (injection drug use primarily)– 4-5 times more common than HIV – NOT vaccine-preventable!