Hepatitis Viruses Flashcards
Acute Viral Hepatitis (2)
Sudden
Followed by complete resolution
Chronic Viral Hepatitis (2)
Prolonged course of active disease with silent asymptomatic or symptomatic infection
Can transmit virus throughout life
Viral Hepatitis Comparison (4)
Source of Virus:
A, E —> Feces
B, C, D —> Blood / body fluids
Transmission route:
A, E —> Fecal-oral
B, C, D —> Percutaneous, Permucosal
Chronic Infection:
A, E —>No
B, C, D —> Yes
Prevention: A, B —> Vaccine C —> Blood donor screening; Behavior modification D —> HBV Vaccine E —> Ensure safe drinking water
Why is Chronic Hepatitis difficult to diagnose?
Often ASYMPTOMATIC with only enlarged tender liver and mildly elevated liver enzymes
HAV- General Characteristics (2)
ssRNA
Non-enveloped
HAV- Clinical Features (3)
Children —> ASYMPTOMATIC
Adults —> MILD
Pregnant —> MORE SEVERE
HAV- Pathogenesis (2)
REPLICATES in DIGESTIVE TRACT then spreads to liver
EXCRETED in STOOLS for TWO WEEKS PRECEDING ONSET of SYMPTOMS
HAV- Complications
FULMINANT HEPATITIS RARE
Where are HAV outbreaks common?
Nurseries
HEV- Case to case transmission??
Uncommon
LARGE INOCULUM needed to establish infection
HEV- Viremia?
Transient (NOT persistent)
HEV- Clinical Features (2)
ACUTE
SELF-LIMITING
HEV- Age?
Young adults
HEV- Immunity
Short-term memory
HEV- Complications
FULMINANT HEPATITIS in PREGNANT
HBV- General Characteristics (2)
ENVELOPED
DOUBLE STRANDED DNA
HBV- Antigens (3)
HBsAg —> SURFACE (COAT) protein
HBcAg —> INNER CORE protein
HBeAg —> SECRETED protein
HBV- Transmission
BODY FLUIDS (blood, semen, vaginal fluids, menstrual blood, saliva)
HBV- Complications (3)
FULMINANT HEPATITIS RARE
CIRRHOSIS
HEPATOCELLULAR CARCINOMA
HBV- Risk
Males > Females
HBV- Window Phase
The period from 24-32 weeks when neither free HBsAg nor its antibody (Anti-HBsAg) can be detected
The failure to detected Anti-HBsAg early in infection is not because of lack of antibodies; instead, they are undetectable because they are complexed with large amount of antigen that is shed from infected cells
HBs
HBsAg
- Live virus and infection
HBsAb
- Recovery and immunity to HBV
- Develops in people successfully vaccinated against HBV
HBe
HBeAg
- Active infection
- Determines how contagious you are
- Used to monitor effectiveness of treatment
HBeAb
- IgG = old infection
HBc
HbcAb
- Appears 1 month after active infection
- Persists for life as they are not protective
- Indicated previous or ongoing infection
- Used by blood banks to screen
IgM = New infection
Acute HBV
HBsAg
HBeAg
Anti-HBcAg (IgM)
Chronic HBV High Infectivity
HBsAg
HBeAg
Anti-HBcAg (igG)
Chronic HBV Low Infectivity
HBsAg
Anti-HBeAg
Anti-HBcAg (IgG)
Recovery
Anti-HBsAg
Anti-HBeAg
Anti-HBcAg (IgG)
Immununized
Anti-HBsAg
HBV- Active Immunization
Serum derived —> Prepared from HBsAg
Recombinant HBsAg —> By genetic engineering in yeasts
HBV- Passive Immunization
Administered to non-immune individuals following exposure to HBV- infected blood
E.g. Needle stick injury
HCV- General Characteristics (2)
ssRNA
Enveloped
HCV- Reservoirs (2)
Humans
Chimpanzees
HCV- Progession (4)
Alcohol consumption
Males
Co-infection with HIV or HBV
Older
HCV- Pathogenesis (2)
Enters bloodstream
Infects hepatocytes
HCV- Clinical Manifestations (3)
Milder than HBV
Most ASYMPTOMATIC
Most PERSISTENT liver infection leading to CHRONIC ACTIVE HEPATITIS
HCV- Diagnosis (2)
IgG —> EXPOSURE NOT INFECTIVITY
RNA —> INFECTIVITY
HDV- General Characteristics (2)
DEFECTIVE virus (can’t replicate on its own) Cannot code for its own surface proteins and so in order to produce more virus particles; it needs a HELPER virus —> HBV
HDV- Acquired
Along with HBV (CO-INFECTION) or as SUPER-INFECTION of an already HBV-INFECTED individual
HDV- Coinfection
- Exacerbates ACUTE disease
- FULMINANT HEPATITIS more likely
HDV- Superinfection
- CHRONIC liver disease accompanied by CIRRHOSIS
