Download Hepatitis A-E Viruses part ІІ

INFLAMMATON OF THE LIVER
Hepatitis D-C-E Viruses
part ІІ
Dr. Osama AL Jiffri
Hepatitis D (Delta) Virus
Hepatitis D Structure
 Hepatitis D virus is found only in patients
infected with hepatitis B
 Enveloped with SS RNA and forms a small
particle coated with HBsAg 35-40nm
 Only antigen encoded is the delta antigen
Hepatitis D (Delta) Virus
d antigen
HBsAg
RNA
Hepatitis D Virus
Modes of Transmission
• Percutanous xposures
–injecting drug use
• Mucosal exposures
–sex contact
Geographic Distribution of HDV Infection
Taiwan
Pacific Islands
HDV Prevalence
High
Intermediate
Low
Very Low
No Data
Hepatitis D:Pathogenesis
 Pathogenesis
– Immune mediated
– Co-infection- infection with B at the same time
(more severe)
– Superinfection: acquisition of Hep D in
chronically Hep B
Sequelae of hepatitis D virus
Hepatitis D - Clinical Features
• Coinfection
–severe acute disease
–low risk of chronic infection
• Superinfection
–usually develop chronic HDV infection
–high risk of severe chronic liver
disease
Hepatitis D: Diagnosis
 Serology:
 ELISA test (only on research )
Hepatitis D - Prevention
• HBV-HDV Coinfection
Pre or postexposure prophylaxis to prevent HBV
infection
• HBV-HDV Superinfection
Education to reduce risk behaviors among
persons with chronic HBV infection
• Alpha interferon may help reduce hepatocellular
damage
Hepatitis C
Non A -non B HEPATITIS
Hepatitis C
Structure and Classification
 Unclassified virus, Member of the flavivirus
family (other members yellow fever and
dengue)
 Enveloped single stranded RNA virus
 Humans and chimpanzees only known
reservoirs (virus-specific protein in blood)
 6 serotypes (genotypes) and multiple
subtypes based on high variability of
envelope glycoproteins
Exposures Known to Be
Associated With HCV Infection
 Injecting drug use
 Transfusion, transplant from infected donor
 Occupational exposure to blood
– Mostly needle sticks
 Iatrogenic (unsafe injections)
 Birth to HCV-infected mother
 Sex with infected partner
– Multiple sex partners
Sources of Infection for
Persons With Hepatitis C
Injecting drug use 60%
Sexual 15%
Transfusion 10%
(before screening)
Occupational 4%
Other 1%*
Unknown 10%
* Nosocomial; iatrogenic; perinatal
Source: Centers for Disease Control and Prevention
Prenatal Transmission of HCV
 Transmission only from women HCVRNA positive at delivery
– Average rate of infection 6%
– Higher (17%) if woman co-infected with
HIV
– Role of viral titer unclear
 No association with
– Delivery method
– Breastfeeding
HCV: Pathogenesis
 Blood-borne pathogen that infects hepatocytes
 Much like Hep A and B, liver damage and clinical
illness
 Likely cytotoxic T cells that mediate most of the
damage
 Like other chronic liver diseases (Hep B and
chronic alcoholism), can cause hepatocellular ca
(HCC)
Features of Hepatitis C Virus
Infection
Incubation period
Acute illness (jaundice)
Case fatality rate
Chronic infection
Chronic hepatitis
Agerelated
Cirrhosis
Mortality
Average 6-7 weeks
Range 2-26 weeks
Mild (<20%)
Low
60%-85%
10%-70%
<5%-20%
1%-5%
Hepatitis C: Clinical Features
 Acute infection asymptomatic in over 80% of
patients, when present, acute illness usually
mild
– Acute symptoms include jaundice, nausea,
abdominal pain, loss of appetite, dark urine
Chronic Hepatitis C
Factors Promoting Progression or
Severity
 Increased alcohol intake
 Age > 40 years at time of infection
 HIV co-infection
 Other
– Male gender
– Chronic HBV co-infection
Hepatitis C: Diagnosis
 Dose not grow in cell culture
 ELISA-a serological test which is usually positive
within 2-5 months after infection
– 3rd generation assays now 99% specific and sensitive
 Confirmatory testing
– PCR (positive 1-2 weeks post infection) both
quantitative and qualitative (I.e. ye/no) available
– RIBA (recombinant immunoblot assay)- looks for 2 or
more antibodies to HCV viral antigens
 Genotype testing done when treatment anticipated
HCV Infection Testing Algorithm
for Diagnosis of Asymptomatic Persons
Screening Test for AntiHCV
Negative
STOP
Positive
OR
RIBA for Anti-HCV
Negative
STOP
Negative
Indeterminate
Additional Laboratory
Evaluation (e.g. PCR, ALT)
Negative PCR,
Normal ALT
Positive PCR,
Abnormal ALT
Source: MMWR 1998;47 (No. RR 19)
NAT for HCV RNA
Positive
Medical
Evaluation
Positive
Hepatitis C Therapy
 Systemic effects (fatigue, myalgias,
depression, anemia)
 Standard of care is pegylated interferon
alpha and ribavirin
 Overall response rate to treatment is 4050% (higher for non 1 genotypes)
Hepatitis E Virus
Hepatitis E
 Non-enveloped single stranded RNA virus
 Resembles calicivirus or Norwalk agent
 Similar illness to Hep A except high mortality
in pregnant women
Geographic Distribution of Hepatitis E
Hepatitis E - Epidemiology
• Most outbreaks associated with
fecally contaminated drinking water
• Minimal person-to-person transmission
• U.S. cases usually have history of travel
to HEV-endemic areas
Hepatitis E - Clinical Features
• Incubation period:
• Case-fatality rate:
Average 40 days
Range 15-60 days
Overall, 1%-3%
Pregnant women,
15%-25%
• Illness severity:
Increased with age
• Chronic sequelae:
None identified
Hepatitis E Virus Infection
Symptoms
ALT
IgG anti-HEV
Titer
IgM anti-HEV
Virus in stool
0
1
2
3
4
5
6
7
Weeks after Exposure
8
9
1
0
1
1
1
2
1
3
Prevention and Control Measures for Travelers
to HEV-Endemic Regions
• Avoid drinking water (and beverages with
ice) of unknown purity, uncooked
shellfish, and uncooked fruit/vegetables
not peeled or prepared by traveler
• IG prepared from donors in Western
countries does not prevent infection
• Vaccine?
Heptitis viruses
A
B
C
D
E
Virus genome
SSRNA
DSDNA
SSRNA
SSRNA
Unknown
Transmission
faecal- Sex,blood, Blood,other
oral,food congenital
,water
As for
HBV
water-borne,
epidemic
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