Viral Hepatitis - Historical Perspective Infectious A E Enterically transmitted Viral hepatitis NANB Serum B D F, G,? other C Parenterally transmitted
Before the discovery of hepatitis A virus (HAV) and hepatitis B virus (HBV) during the 1960s and 1970s, patients with viral hepatitis were classified based on epidemiological studies as having either infectious (transmitted person to person by the fecal-oral route) or serum (transmitted by transfusion of blood products) hepatitis.
Six known Hepatitis type A virus (Picornaviridae) Hepatitis type B virus (Hepadnaviridae) Hepatitis type C virus (Flaviviridae) Hepatitis type D virus (viroid, unclassified) Hepatitis type E virus (unclassified) Hepatitis type G virus (Flaviviridae)
Viral Hepatitis - Overview Source of virus A B C D E feces blood/ blood-derived body fluids Type of Hepatitis 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/postexposure immunization pre/postexposure immunization blood donor screening; risk behavior modification pre/post- ensure safe exposure drinking immunization; water risk behavior modification
RNA Picornavirus Single serotype worldwide Acute disease and asymptomatic infection No chronic infection Protective antibodies develop in response to infection - confers lifelong immunity
Hepatitis A is caused by HAV, a 27-nm ribonucleic acid (RNA) agent that is classified as a picornavirus. Only one serotype has been observed among HAV isolates collected from various parts of the world. HAV causes both acute disease and asymptomatic infection. HAV does not cause chronic infection. Total antibody to HAV develops in response to infection and confers lifelong immunity from future HAV infection.
HEPATITIS A - CLINICAL FEATURES Jaundice by <6 yrs <10% age group: 6-14 yrs 40%-50% >14 yrs 70%-80% Rare complications: Incubation period: Chronic sequelae: Fulminant hepatitis Cholestatic hepatitis Relapsing hepatitis Average 30 days Range 15-50 days None
HEPATITIS A VIRUS TRANSMISSION Close personal contact (e.g., household contact, sex contact, child day-care centers) Contaminated food, water (e.g., infected food handlers) Blood exposure (rare) (e.g., injection drug use, rarely by transfusion)
Hygiene (e.g., hand washing) Sanitation (e.g., clean water sources) Hepatitis A vaccine (pre-exposure) Immune globulin (pre- and postexposure)
Hepatitis B
Hepatitis B - Clinical Features Incubation period: Average 60-90 days Range 45-180 days Clinical illness (jaundice): <5 yrs, <10% ³5 yrs, 30%-50% Acute case-fatality rate: 0.5%-1% Chronic infection: <5 yrs, 30%-90% ³5 yrs, 2%-10% carrier state (350m ) Premature mortality from chronic liver disease: 15%-25%
Acute Viral Hepatitis Source: CDC
Hepatitis B Virus
Spherical. enveloped. 42-47nm diameter d/s DNA an RNA-dependent DNA polymerase (i.e. reverse transcriptase) family Hepadnaviridae
When they occur, the signs and symptoms of viral hepatitis can include: Fever Fatigue Loss of appetite Nausea Vomiting Abdominal pain Jaundice Dark urine Clay-colored stool Joint pain
Main Ways to Get Hepatitis B Having sex without condoms with someone who has hepatitis B Sexual Being born to a mother who has hepatitis B Perinatal Sharing needles and syringes Parenteral You can pass hepatitis B to others if you have just gotten the virus (acute hepatitis) or if you are a carrier of the virus (chronic hepatitis).
How does a baby get hepatitis B from mother? If you have hepatitis B and a tiny bit of your blood gets inside your baby at birth.
Passive immunization Hyperimmune hepatitis B immunoglobulin HBIG Active immunization Vaccine HBsAg
Flaviviridae
+strand RNA. Transmission primarily through blood products Sexual transmission can occur Most acute infections are subclinical However, most will develop chronic hepatitis
Features of Hepatitis C Virus Infection Incubation period Average 6-7 weeks Range 2-26 weeks Acute illness (jaundice) Mild (<20%) Case fatality rate Low Chronic infection 60%-85% Chronic hepatitis Age- 10%-70% related Cirrhosis <5%-20% Mortality from CLD 1%-5%
HCV not spread by kissing, hugging, sneezing, coughing, food or water, sharing or drinking glasses, or casual contact Do not exclude from work, school, play, childcare or other settings based on HCV infection status
Screen and test donors Virus inactivation of plasma-derived products Vaccinate against hepatitis A and/or hepatitis B Safe injection and infection control practices Avoid Direct Exposure to Blood
Do not donate blood, body organs, other tissue or semen Do not share items that might have blood on them personal care (e.g., razor, toothbrush) home therapy (e.g., needles) Cover cuts and sores on the skin.
Targets the liver Cause focal necrosis, leading to larger areas of necroses Jaundice If recovery occurs, liver function often returns to normal Substantial damage cannot be reversed HBV and HCV have been associated with hepatocellular carcinomas HBV can cause rash, arthritis, vasculitis and glomerulonephritis Fatality Rates Hep A: <0.5% (increases after age 40) Hep B: 1-2% (chronic in 5-10% of infections) Hep C: 0.5-1% (chronic in 70-90% of infections)