LMP301 Lecture 16: Viral Hepatitis Flashcards
Causes of hepatitis
- drugs
- toxins
- bacteria
- viruses
- parasites
define: hepatitis
inflammation of the liver
drugs that may cause hepatitis
- anticonvulsants
- corticosteroids
- alcohol
- tylenol/asprin overdose
toxins that may cause hepatitis
- DDT
- mushrooms
bacteria that may cause hepatitis
- thyphoid fever
viruses that may cause hepatitis
- hepatitis A, B, C, D, E, G
- CMV
- EBV
parasites that may cause hepatitis
tapeworm
clinical symptoms of viral hepatitis
- enlarged liver
- elevated liver enzymes
- change colour of urine/feces
- accumulation of biliburin (jaundice)
on a virus particle, what can be used to identify the strain?
- ssDNA or RNA
- surface proteins (HBsAg)
define: antigen (Ag)
a substance (protein) that prompts the generation of antibodies -> immune response
define: antibody (Ab/IgG/IgM)
proteins produced by B-cells which play an immunological role; identify & neutralizes foreign particles through antigens
Which antibody is first released when there is an immune response? Which is released after?
IgM, then IgG
IgM indicates…
primary immune response
__ are produced during the primary immune response
memory lymphocytes
The virus particle is surrounded by…
capsule coat
The genetic material of virus is in the form of…
DNA or RNA (single or double stranded)
what is directly inside the capsule coat?
Viral nucleocapsid (HBcAg)
HBcAg
Viral nucleocapsid
HBeAg
particles associated with nucleocapsid
Where are HBeAg found?
inside the viral capsid (HBcAg)
When does the production change from IgM to IgG?
after mature B cells are formed
What is it called when IgG production begins and IgM production stops?
class-switching
class-switching is….
a stable change in the B-cell’s genome, and is transmitted to all progeny cells
Lifecycle of a virus
- enters hepatocyte (capsule coat removed), viral DNA moves to nucleus of host
- viral dsDNA -> cccDNA -> template for viral mRNA
- viral mRNA transcription & assembly of new viral particles
- viral proteins assemble around DNA core
- new viral particles released from outer membrane of the host
dsDNA -[?]-> cccDNA
cellular enzymes
___ can persist in the hepatocyte during chronic infection
cccDNA
cccDNA is genetic material of…
virus
Steps of viral reproduction
- Uncoating
- Repair (formation of cccDNA)
- Transcription
- Translation
How does release of viral particles determine host cell health?
If a little bit of the particle is released at a time, host lives
if all released, host dies
If the host cell dies, what happens to the viral production cycle?
it halts
Describe the Hep A virus
- small
- ssRNA (single protein core)
- no surface proteins to identify
how is Hep A virus transmitted?
fecal-oral
- person-to-person contact
- contaminated water
- poor hygiene & sanitation
Who is at high risk for Hep A?
- children in daycare
- travelers to places where sanitation is bad
onset of symptoms for Hep A
- very abrupt
- lasts 1 ~ 8 weeks
what is a common clinical symptom of Hep A? How many adults develop this symptom?
jaundice
70-80%
What is responsible for causing Hep A?
HAV
where does HAV replicate?
in liver
how does HAV leave the body?
through stool
when is HAV most infectious (found in stool)?
first 2 weeks of contracting disease, a lot of HAV will be found in the stool
When does [HAV] decline in the stool?
after jaundice appears
what happens to those people who have Hep A?
will recover, and develop immunity to HAV
what is a marker used for diagnosing/confirming recent/acute HAV infection?
anti-HAV IgM + ALT (liver enzyme)
what is a marker that indicates immunity to HAV?
anti-HAV IgG, and the absence of anti-HAV IgM in serum
clinical symptoms of Hep A appears about…
2 weeks after infection, and lasts until week 8 (duration: 6 weeks)