Hepatitis and Prions

Hepatitis viruses are grouped based on tissue tropism. Where do they infect then?

Liver

Common symptoms of a hepatitis virus include:

fatigue, headache, anorexia, nausea, abdominal pain, jaundice, dark colored urine

Hepatitis A is a…

naked ssRNA virus

Hepatitis A is an enteric virus. What does that mean?

viruses that primarily infect the gastrointestinal tract, often spreading via the fecal-oral route

What characterizes a Hep A infection?

Self-limiting with complete recovery taking months (NO chronic infection with very low mortality rate)

What gives the diagnosis of Hep A?

Demonstration of IgM and IgG to HAV

Hep B is a …

partially dsDNA virus

How is Hep B transmitted??

Bloodborne and body fluids (semen, vaginal fluid, saliva)

Where is the Hep B surface antigen (HBsAg) found?

Circulating in bloodstream

Where is the Hep B core antigen (HBcAg) found?

On virion

Where is the Hep B envelope antigen (HBeAg) found?

On the virion

What does the detection of Anti-HBs show?

Protection through either vaccine or past infection

What does the detection of Anti-HBc show?

The person has been exposed to HBV at some point in their life

What three things for HBV diagnosis?

1. clinical presentation

2. specific markers

3. AST or ALT levels

Ok, HBsAg and HBeAg are the first to appear. They appear either in…

acute or chronic infections

HBsAg sticks around until…

seroconversion

Which HBV antigen is related to infectivity and indicates the number of virions present?

HBeAg

What antibody is used to diagnose an acute HBV infection?

IgM anti-HBc

There is also an IgG anti-HBc that indicates…

a past or current infection

What is the core window?

The period between detecting HBsAg and anti-HBs

Little mnemonic to remember order of appearance

Start at surface, go through earth, reach the core, go back to core, and reach surface again —→ HBsAg, HBeAg, anti-HBc, anti-HBe, anti-HBs

Alright describe the actions of HBsAg and HBeAg

First responders

Describe the action of anti-HBc IgM

First to respond to antigens, rises quick and drops first

Describe the action of anti-HBe

Rises and gradually drops (indicates reduced infectivity)

Describe the action of anti-HBc IgG

Rises and remains high

Describe the action of anti-HBs

Appears after 6 months and remains high

Hep C is a…

enveloped ssRNA

What is the transmission for HCV?

Bloodborne pathogen

Out of HAV, HBV, and HCV, which has the highest mortality rate?

HCV

50% of people infected with HCV become…

long term carriers

20-30% of people with HCV develop…

cirrhosis of the liver

Hep D is a…

circular ssRNA

Why is HDV known as a defective virus?

It requires HBV for replication

What percent of people with chronic HDV develop cirrhosis?

60%

What are the two clinical forms of HDV?

Coinfection and Superinfection

What is HDV coinfection?

Simultaneous infection with HBV

What is HDV superinfection?

Higher risk of rapid onset of liver failure with chronic HBV infection

Hep E is a…

naked ssRNA virus

How is Hep E transmitted?

Same as Hep A - fecal oral route

Transmissible Spongiform Encephalopathies (TSEs) are known as…

Prions

What is a known prion disease in humans?

Kuru and Creutzfeldt-Jakob disease (CJD)

What is the primary prion disease in deer and elk?

Chronic wasting disease

How are prion diseases trasmitted?

Ingestion of infected meat and exposure to infected tissue

Prions are highly resistant to inactivation so instrumentation has to…

destroyed