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!