Download HEPATITIS

Cheryl Ryan
Renee Baker
 Hepatitis is the inflammation of the liver caused by a
virus .
 The disease targets liver cells, hepatocytes.
 There are currently eleven viruses recognized as
causing hepatitis:
2 are herpesviruses
9 are hepatotropic ( 5 are well characterized: A, B,
C, D, and E)
Taxonomy
 Hepatitis A Virus (HAV) - Picornaviridae, Hepatovirus
 Hepatitis B Virus (HBV) - Orthohepadnavirus,
Hepodnaviridae
 Hepatitis C Virus (HCV) - Flaviviridae
Ecology of the Virus
 Biological vectors – humans, contaminated food and
water, contaminated needles
 HAV- can live outside the body for months, depending
on the environmental conditions.
 HBV - can survive outside the body at least 7 days.
 HCV- can survive outside the body and still transmit
infection for 16 hours, but not longer than 4 days.
Infection Process- Hepatitis A
 HAV enters the gut
 replicates in the
alimentary tract
 spreads to infect the liver
 multiplies in hepatocytes
Infection Process – Hepatitis B & C
 The virus attaches to the
liver cell and is
transported inside.
 Viral particles are
released into the
nucleus.
 The virus is replicated
and then released from
the cell.
Symptoms
 Jaundice
 Fatigue
 Abdominal pain
 Loss of appetite
 Nausea
 Diarrhea
 Fever
 Joint Pain ( HBV)
 Dark Urine (HCV)
Diagnostic Tests
 Serological testing – presence of IgM antibody to HAV
 Blood Tests (HBV and HCV)
Treatments
 HAV – vaccine is the best prevention
 HBV – vaccine
 HCV – there is no vaccine available
 Who should be vaccinated?
 Who should not be vaccinated?
Prevention
 Surest way to prevent transmission is to avoid sexual contact
with infected persons. (HBV and HCV)
 Never inject illegal drugs.
 Do not share personal care items.
 Consider the risks of getting tattoos and piercings.
 Wash hands with soap and water after using the bathroom,
changing a diaper, and before preparing and eating food. (HAV)
Epidemiology
 HAV – Before the vaccine became available there were
35,000 cases per year. Number of new hepatitis A
cases: 5,683 (2004)
 Transmitted by fecal-oral contamination, sexual contact,
illegal drug use, and consumption of contaminated
food.
 As little as 10-100 viral particles are needed to infect the
host.
 1/3 have evidence of past infection.
 Hepatitis E is similar to Hepatitis A.
Epidemiology (cont.)
 HBV – Generally transmitted through body fluids and
sexual contact, illegal drug use and needle sticks, and
healthcare settings.
 As of 1997 more than 80 countries had adopted routine HBV
vaccinations for children.
 The number of new infections per year declined from 260,000
in the 1980’s to about 60,000 in 2004.
 Hepatitis D only occurs when the host is infected with HBV.
 Estimated 1.25 million chronically infected Americans, of
whom 20-30% acquire their infection in childhood.
Epidemiology (cont.)
 HCV – Transmission occurs when contaminated blood
enters the body of a person who is not infected.
 Most infections are due to illegal injection drug use.
 Estimated 4.1 million (1.6%) of Americans have been
infected with HCV.
 The number of new infections has declined from
approximately 240,000 in the 1980’s to about 26,000 in
2004.
 Transfusion associated cases now occur in less than 1 per
2 million transfused units of blood.
Morbidity and Mortality
 HAV – There is no chronic infection.
 About 15% of people infected will have prolonged or
relapsing symptoms over a 6-9 month period.
 HBV -Each year, approximately 600,000 deaths occur
worldwide (2003).
 Death from chronic liver disease occurs in 15-25%
 HCV – 1-5% of infected persons die from chronic liver
disease.
 Leading cause for liver transplants.
Latest Research
 Alpha Interferon which results in sustained remission
in selected patients is the only available therapy for
treatments of persons with chronic hepatitis C.
 Prevention of HCV infection by vaccination is likely to
be challenging if ongoing viral mutations continue.
References
 www.cdc.gov
 www.clinchem.org
 http://www.nlm.nih.gov/medlineplus/hepatitisc.htm
 www.webmd.com
 http://digestive-disorders.health-cares.net/viral
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hepatitis.php
http://web.uct.ac.za/depts/mmi/jmoodie/dihep.html
www.journals.asm.org
www3.niaid.nih.gov
Sherwood, LM, Willey J, Woolverton C. Microbiology. 200