Lecture 11: Virology -Hepatitis Viridae Flashcards
1) Viral hepatitis and liver enzyme elevation 2) Epidemiology, serology, and treatment of Hepatitis A virus 3) Transmission, pathogenesis, serology, and treatment of Hepatitis B virus 4) Transmission, manifestations, diagnosis, and treatment of Hepatitis C virus 5) Hepatitis D, E, and G viruses
Viral Hepatitis
Infection of liver hepatocytes by viruses
5 RNA Hepatitis Viruses
Hep A (HAV) Hep C (HCV) Hep D (HDV) Hep E (HEV) Hep G (HGV)
1 DNA Hepatitis Virus
Hep B (HBV)
Acute Viral Hepatitis
- what?
- ________ incubation period
- symptoms
- enzymes produced
sudden illness with a mild to severe course followed by complete resolution
- variable incubation period
- flu like symptoms
- 1-2 wks later patient develops jaundice
- necrosis of hepatocytes produces enzymes aspartate aminotransferase (AST), alanine aminotransferase, gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase
Chronic Viral Hepatitis
- what?
- which strains?
- why is diagnosis difficult?
prolonged course of active disease or silent asymptomatic infection
- HBV, HCV, & HDV can cause chronic hep
- diagnosis difficult due to patient being asymptomatic with only an enlarged tender liver and mildly elevated liver function enzyme levels
Hepatocytes produce ____ and ____. The cells that line the bile canaliculi produce _______________ and ______.
AST; ALT
alkaline phosphatase; GGT
Cell necrosis results in release of ___ and ____
AST; ALT
Initially there is high ___ and ____ & little elevation in _____________ and _____
AST; ALT
alkaline phosphatase; GGT
As infection worsens, the liver ____ and the canaliculi _________, resulting in a backup of ____________ in the blood
swells; narrows; bilirubin
Hepatitis A Virus
- structure
- family?
- transmission
-naked icosahedral capsid with (+) ssRNA nucleic acid
family picornaviridae
-transmitted by fecal-oral route
Hepatits A Virus
-Epidemiology
- 6000 cases reported each year in the US
- Poor hand washing, persons ingesting fecally contaminated drinking water, close person-to-person contact in institutions such as day care
Hepatitis A Virus
- Serology
- > what part is antigenic?
- > which immuniglobulins?
- > active vs old infection
- HAV capsid is antigenic; host production of anti HAV IgM and later anti-HAV IgG
- Patient with active infection has anti-HAV IgM detectable in the serum
- Anti-HAV IgG indicates old infection, no active disease
Hepatitis A Virus
-Treatment
- inactivated Hepatitis A vaccine recommended for high risk adults
- once exposed, pooled immune serum globulin will prevent or decrease the severity of infection, if given early
Hepatits B Virus
- Structure
- > family
- > size
- > genome
- intact virus is called what? and is composed of?
- Hepadnavirus
- HBV= BIG and BAD
- Big virus (42 nm) with an enveloped icosahedral capsid and circular dsDNA
- intact virus is callled Dane particle composed of an envelope and capsid studded with protein spikes
Hepatitis B Virus
-Viral Proteins
4 viral proteins encoded by viral DNA:
1) Capsid protein (hep B capsid antigen) [HBcAg]
2) Envelope protein (hep B surface antigen) [HBsAg] -anti-HBsAg are protective
3) Multifunctional reverse transcriptase/DNA polymerase
4) Nonstructural regulatory protein, X protein