Hepatitis A through E

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Hepatitis A through E

• Dr. Kevin Forward
• Departments of Pathology, Microbiology and
  Immunology and Medicine
• 473-4109
• kevin.forward_at_cdha.nshealth.ca

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Hepatitis A virus

• A picornavirus single stranded, naked,
  icosahedral
• Spread is almost always by fecal-oral spread.
• Directly from on individual to another.
• From contaminated food and water.
• Epidemiology correlates with sanitation levels
• Very common in developing countries
  but now fairly rare in Nova
  Scotia.
• Disease occurs on a sporadic and an
  epidemic basis.

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Hepatitis A virus (continued)

• The virus is ingested, replicates in the bowel
  wall and spreads via the blood stream to the
  liver
• The incubation period is 2-4 weeks
• Most cases are asymptomatic therefore, cases of
  jaundice only represent the tip of the iceberg
• It does not produce chronic carrier state and has
  no long term sequelae
• Diagnosis is confirmed by demonstrating the
  appearance of IgM antibodies.

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Geographic Distribution of HAV Infection
Anti-HAV Prevalence
High
Intermediate
Low
Very Low
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Hepatitis A Virus Infection
Typical Serologic Course
Symptoms
Total anti-HAV
Abnormal liver tests
Titer
Fecal HAV
IgM anti-HAV
4
5
6
12
24
0
1
2
3
Months after Exposure
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Prevention of Hepatitis A

• Vaccine
• for travellers
• for individuals at high risk of hepatitis A
  because of occupational or other exposure.
• In outbreak settings
• for those that can afford it
• Immune globulin.
• Post exposure (When you need instant protection)

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Hepatitis B

• A double stranded Hepadnavirus.
• Transmitted by parenteral, perinatal and sexual
  routes
• Most 2/3 are asymptomatic.
• Hepatitis may last for months.
• Patients who become carriers develop chronic
  active or persistent hepatitis.
• 1 die of fulminant hepatitis.
• Very infectious, app 20 of needle sticks result
  in infection in non immune individuals

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Hepatitis B (continued)

• 350,000,000 carriers worldwide.
• 1,000,000,000 have serologic evidence of past
  infection.
• In the US and Canada, 0.1-0.3 are carriers.
• Individual risk reflects ethnic origin and
  lifestyle
• In central Africa and Southeast Asia the carrier
  rate can exceed 8
• Chances of developing the carrier state depend on
  the age on infection (very high for neonates, app
  5 for adults)

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Consequences of chronic hepatitis B

• No/minimal liver injury
• Chronic active hepatitis
• Cirrhosis of the liver
• Liver failure
• Portal hypertension
• Hepatocellular carcinoma

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Geographic Distribution of Chronic HBV Infection
HBsAg Prevalence
?8 - High
2-7 - Intermediate
lt2 - Low
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42 nm Dane particle, infectious form
20 nm spherical particle
filamentous form
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Chronic Hepatitis B Virus Infection Typical
Serologic Course

Acute (6 months)
Chronic (Years)
HBeAg
anti-HBe
HBsAg
anti-HBc
Titer
IgM anti-HBc
Years
0
4
8
12
16
20
24
28
32
36
52
Weeks after Exposure
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Acute Hepatitis B Virus Infection with Recovery
Typical Serologic Course
Symptoms
Titer
anti-HBs
IgM anti-HBc
HBsAg
0
4
8
12
16
24
28
32
52
100
20
36
Weeks after Exposure
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Prevention and treatment of Hepatitis B

• Post exposure prevention HBIG (needle stick)
  vaccination.
• Vaccine
• Universal for kids
• Directed for others
• Health care workers at risk
• Hemodialysis patients
• Recipients of large amounts of blood products
• Sexual contacts of carriers
• Gay males with multiple partners
• Sex trade workers
• Treatment with interferon and lamivdine in
  patients with chronic hepatitis.

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Diagnosis of Hepatitis B

• Detection of surface antigen in patients serum
  (HBsAg)
• Detection of antibodies to hepatitis B surface
  antigen (anti HBs)
• Evidence of old infection
• Evidence of immunity from vaccine
• Liver biopsy to determine the extent of liver
  damage

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Hepatitis C

• Small enveloped RNA virus (Flavivirus).
• Widely distributed.
• Usually parenterally transmitted although less
  infectious than HBV (needle stick risk is 2 vs
  20)
• Approximately 15,000 cases yearly in Canada.
• Approximately 1 of adults are positive.

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Hepatitis C (continued)

• Occurs as sporadic disease in IV drug users and
  others without obvious (or admitted) source.
• Intimate contact rarely transmits disease.
• 75 mild or asymptomatic.
• Incubation period is 2-20 weeks.
• 40-60 may get chronic liver disease (Note that
  this is much higher than for HBV)
• 20 may develop cirrhosis.
• Hepatoma may develop as a long term sequelae.

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Hepatitis C Virus Infection
Typical Serologic Course
anti-HCV
Symptoms
Titer
ALT
Normal
6
1
2
3
4
0
1
2
3
4
5
Years
Months
Time after exposure
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Diagnosis of Hepatitis C

• Antibody test (EIA).
• Polymerase chain reaction (PCR) to detect RNA in
  patients serum (an indicator of disease
  activity).
• Liver biopsy to determine disease activity.

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Prevention and treatment of Hepatitis C

• There is no vaccine and none on the way
• Good public health measures
• Screening of transfused blood products.
• Organ donor screening
• Standard precautions in hospitals
• Needle exchange programs
• Interferon and ribavirin administered over 6-12
  months for chronic infections results a gt60 cure
  rate
• Interferon treatment leads to numerous side
  effects eg Fever, chills, rigors, muscle aches
  and pains

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Hepatitis D

• Rare infection due to an incomplete RNA virus
  that requires presence of hepatitis B.
• Found mostly in IVDUs.
• Infection may occur concurrently or may follow
  hepatitis B infection.
• Concurrent infection (getting both in the same
  needle) may be more severe.

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Hepatitis D (Delta) Virus

? antigen
HBsAg
RNA
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Hepatitis E

• A calicivirus (RNA)
• Almost never seen in North America
• Disease characteristics very similar to
  hepatitis A
• Fecal-oral spread
• Lack of chronicity
• Low fatality rate (except in pregnancy)

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Geographic Distribution of Hepatitis E
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Viral Hepatitis - Overview

Type of hepatitis
A
B
C
D
E
Source of
feces
blood/
blood/
blood/
feces
virus
blood-derived
blood-derived
blood-derived
body fluids
body fluids
body fluids
Route of
fecal-oral
percutaneous
percutaneous
percutaneous
fecal-oral
transmission
permucosal
permucosal
permucosal
Chronic
no
yes
yes
yes
no
infection
Prevention
pre/post-
pre/post-
blood donor
pre/post-
ensure safe
exposure
exposure
screening
exposure
drinking
immunization
immunization
risk behavior
immunization
water
modification
risk behavior
modification