Hepatitis viruses Flashcards
What is the structure of hepatitis A virus?
Non-enveloped positive-sense single-stranded RNA
What is the structure of hepatitis B virus?
Enveloped double-stranded DNA with an RNA intermediate (Baltimore class 7)
What is the structure of hepatitis C virus?
Enveloped positive-sense single-stranded RNA
What is the structure of hepatitis D virus?
Defective, enveloped negative-sense single-stranded RNA
What is the structure of hepatitis E virus?
Non-enveloped positive-sense single-stranded RNA
Which hepatitis viruses have the same structure?
HAV and HEV: non-enveloped +ssRNA
Which hepatitis virus is a DNA virus?
HBV: dsDNA with an RNA intermediate
How is HAV transmitted?
- Fecal–oral route (from contaminated food or water)
- Minor route: sexual transmission, especially in MSM
How is HBV transmitted?
- Blood (from transfusions, injection drug use, needlestick injuries)
- Vertical transmission
- Sexual transmission
- Organ transplantation
- Resulting from hemodialysis
How is HCV transmitted?
- Blood (from transfusions, needlestick injuries, and especially injection drug use)
- Organ transplantation
- Resulting from hemodialysis
- Vertical transmission (to a lesser extent than HBV)
- Sexual transmission (to a lesser extent than HBV)
What is the most common method of HCV transmission?
Blood transmission from injection drug users
How is HDV transmitted?
- Blood (from transfusions, injection drug use, needlestick injuries)
- Vertical transmission
- Organ transplantation
- Resulting from hemodialysis
How is HEV transmitted?
Fecal–oral route (from contaminated food or water)
What is the incubation period of the hepatitis viruses?
- HAV, HEV: a few weeks
- HBV, HCV, HDV: a few months
What are the diseases caused by all the hepatitis viruses?
- Acute hepatitis: jaundice, nausea, vomiting, anorexia, elevated liver enzymes (ALT, AST)
- Fulminant hepatitis (acute liver failure) in a minority of patients, leading potentially to death
- Asymptomatic infection
Which hepatitis virus is most prominently associated with fulminant hepatitis?
HEV in pregnant women or people with chronic protein malnutrition
Which hepatitis viruses can cause chronic infection?
HBV, HCV, and HDV
What are the features and course of chronic infection with hepatitis viruses?
- The viruses continue to be present in the body for more than 6 months
- The infections progresses first to cirrhosis and then to hepatocellular carcinoma
What is the course of infection with HAV and HEV?
The infections either resolve after the acute disease, or lead to death
Which hepatitis viruses are oncoviruses?
HBV, HCV (not HDV as it is defective)
What is the alternative name of HDV?
Delta agent
Which hepatitis virus is needed in addition to HDV to cause infection?
HBV
How are the hepatitis viruses diagnosed?
- HAV: serology—IgM (acute infection or IgG (past infection or vaccination)
- HBV: serology (surface anti-HBV antibody), molecular detection
- HCV: serology, molecular detection
- HDV: serology, molecular detection and confirmation of HBV presence
- HEV: serology
How are the hepatitis viruses treated?
- Acute infection: supportive care
- Chronic HBV: antivirals (nucleoside analogs), interferons
- Chronic HCV: antivirals (direct-acting antivirals; DAAs), interferons
- Chronic HDV: interferons, treatment of HBV
Are there vaccines for the hepatitis viruses?
- HAV: two-dose inactivated vaccine that is highly effective
- HBV: three-dose (given every 3 months) subunit vaccine
- HDV: no vaccine, but vaccination for HBV prevents HDV infection
What is the epidemiology of hepatitis virus infections?
- HBV and HCV have a global incidence of 1.5 million new cases each per year
- 296 million people were living with chronic HBV in 2019
- 58 million people were living with chronic HCV in 2019
