Virology: Hepatitis Viruses

Hepatitis

Hepatitis

inflammation of the liver -results in jaundice -results in elevated levels of serum alanine aminotransferase levels (ALT)

Hepatitis: non-infectious causes

bacterial, fungal, parasites

Hepatitis: viral

hepatitis virus yellow fever virus some herpes virus

Hepatitis: types

A, B, C, D, E, & G Predominant types: A, B, C all have acute infections Chronic infections: B, C, G

Hepatitis A: characteristics

+ss RNA virus naked (non-enveloped) human & primate hosts -restricted to humans though

Hepatitis A: Transmission

fecal-oral: restaurants and frozen foods -GI tract --> blood --> liver -can also be found in other tissues (issue for organ transplants)

Hepatitis A: Disease

acute infection only Incubation: 10-50 days -starts w/ flu-like symptoms -dose dependent (higher does --> earlier onset) age effect

Hepatitis A: Age Effect

Children: -subclinical infection (no disease)- 80-95% -clinical infection (disease)- 5-20% -recovery- 99%

Adult -subclinical infection (no disease)- 10-25% -clinical infection (disease)- 75-90% -recovery- 99%

Hepatitis A: treatment

drugs: none

Hepatitis A: vaccine

whole inactivated --> standard for children -previously only given to people traveling to endemic areas

Hepatitis A: passive immunization

works!

Hepatitis A: Prevention

vaccination, good hygiene, sanitation, clean needles

Hepatitis E: characteristics

originally thought to be Hep A +ss RNA virus Naked (non-enveloped) human, primate, and swine hosts

Hepatitis E: transmission

fecal-oral

Hepatitis E: disease

acute infection only Incubation: 10-50 days -starts w/ flu-like symptoms -dose dependent (higher dose-->earlier onset) no age effect Disease a bit more severe than Hep A dangerous to pregnant women (mortality increase as pregnancy progresses)

Hepatitis E: passive immunization

does NOT work

Hepatitis E: vaccine

none

Hepatitis E: treatment

drugs: none

Hepatitis E: prevention

good hygiene, sanitation, cook pork

Hepatitis G: characteristics

aka GBV-C 15% of population is positive (seropositive) +ss RNA virus enveloped same viral family as Hep C human host -infects hepatocytes and lymphocytes -alters HIV infection (decrease HIV replication)

Hepatitis G: transmission

bodily fluids: sex, blood

Hepatitis G: disease

acute and chronic infections no age effect

Hepatitis G: passive immunization

does NOT work

Hepatitis G: vaccine

none

Hepatitis G: treatment

drugs: none

Hepatitis G: prevention

safe sex, clean needles

Hepatitis B: characteristics

ds DNA virus (pseudo retrovirus) enveloped human host

Hepatitis B: transmission

bodily fluids: sex, blood, birth -transmissibility related to viremia levels (viral load) -10% chronically infected mothers will pass it on to their children

Hepatitis B: disease

acute and chronic infections Incubation: 45-160 days Age effect chronic infection: reactivation (carrier state) -latency

Hepatitis B: age effect

Newborns: -acute: 5-10% -chronic: 90-95%

Adults: -acute: 90-95% -chronic: 5-10%

Hepatitis B: chronic disease

cirrhosis, hepatocellular carcinoma

Hepatitis B: infection of non hepatocytes?

liver transplant does not eliminate the virus

Hepatitis B: vaccine

recombinant protein ("virus-like-particle" aka VLP)

Hepatitis B: treatment

drugs: yes (doesn't clear infection)

Hepatitis B: prevention

safe sex, clean needles, screen blood/blood products, decrease viral loads during birth

Hepatitis C: characteristics

AKA non-A, non-B +ss RNA virus enveloped human and primate hosts

Hepatitis C: transmission

bodily fluids: sex, blood

Hepatitis C: disease

acute and chronic infections Incubation: 5-50 days -initial flu-like symptoms no age effect -15-30% acute -70-85% chronic

Hepatitis C: Chronic infection

cirrhosis, hepatocellular carcinoma

Hepatitis C: infection of non-hepatocytes?

liver transplant does not eliminate the virus

Hepatitis C: vaccine

none

Hepatitis C: passive immunization

does NOT work -tremendous genetic diversity (immune resistance)

Hepatitis C: treatement

drugs: yes -cure infection by blocking continuous replication

Hepatitis C: How does chronic infection form?

results from continuous replication, not by latency

Hepatitis C: prevention

safe sex, screen blood/blood products, clean needles

Hepatitis D: characteristics

-ss RNA virus associate virus -defective (encodes no structural proteins) -utilizes Hep B for structural proteins enveloped human hosts

Hepatitis D: transmission

bodily fluids: sex, blood

Hepatitis D: disease

acute and chronic infections -acute- co-infection of B and D -acute or chronic- superinfection of B then D --chronic can result in cirrhosis no age effect

Hepatitis D: vaccine

none

Hepatitis D: treatment

drugs: none

Hepatitis D: prevention

Hep B vaccination -can't get D without B