ID 13 Flashcards
HBV transmission mnemonic
Parenteral (blood)
sexual (baby-making)
perinatal (birthing)
HDV transmission
same as HBV
most common HEV source
waterborne
incubation HAV - HBV - HCV - HDV - HEV -
HAV - short (weeks) HBV - long (months) HCV - long HDV - superinfection - short, confection = long HEV - short
HDV superinfection
HDV after HBV
HDV coinfection
HDV with HBV
HAV clinical course
Asymptomatic (usually)
Acute
HV clinical course
Initially like serum sickness (fever, arthralgia, rash); may progress to carcinoma.
HDV clinical course?
similar to HBV
HEV clinical course
fulminant hepatitis in pregnant women
HBV prognosis
Most adults have full resolution; minority have chronic infection.
HDV prognosis?
Superinfection –> worse prognosis
HCV prognosis?
majority develop stable, Chronic hep C
HAV liver biopsy
1) hepatocyte swelling
2) monocyte infiltration
3) councilman bodies
HBV liver biopsy
granular eosinophilic “ground glass” appearance.
HCV liver biopsy
lymphoid aggregates with focal areas of macro vesicular steatosis
HDV liver biopsy
similar to HBV
HEV liver biopsy
patchy necrosis
carrier state with hepatitis?
only seen with HBV and HCV
anti-HAV (IgG) significane
IgG antibody indicates prior HAV infection and/or prior vaccination.
*protects against reinfection.
HBsAg indicates…
infection
Anti-HBs indicates…
immunity
Significance of Anti-HBc
If IgM = acute/recent infection.
If IgG = prior exposure or chronic infection
marker of infection during window period?
1) Anti-HBe
2) IgM anti-HBc (may be sole positive marker of infection during window period).
What is HBeAg
Secreted by infected hepatocyte into circulation. Not part of mature HBV virion.
Significance of Anti-HBe
low transmissibility
Marker during incubation period?
HBsAg
Other marker of alcohol use?
ethyl glucuronide
Markers of prodrome, acute disease
HBsAg
IgM anti-HBc
HBeAg
Markers of Chronic high infectivity HBV?
HBsAg
HBeAg
IgG anti-HBc
Markers of Chronic low infectivity HBV?
HBsAg
Anti-HBe
Anti-HBc IgG
markers during recovery?
Anti-HBs
Anti-HBe
Anti-HBc IgG
markers of immunity?
anti-HBs
HIV envelope proteins?
gp120
gp41
gp120?
docking glycoprotein. attaches to host CD4+ cell
gp41?
transmembrane glycoprotein. fusion and entry
p17?
HIV matrix protein
p24?
HIV capsid protein
origin of gp120 and gp41?
Formed from cleavage of gp160 to form envelope glycoproteins.
what is gag?
codes for p24 + p17
what is pol?
gene that codes for reverse transcriptase + aspartate protease + integrase
virus binding mechanism
Binds CD4 + coreceptor (either CCR5 on macrophages in early infection or CXCR4 on T cells in late infection).
heterozygous CCR5 mutation?
slower course
homozygous CCR5 mutation?
immunity
ELISA characteristics
sensitive, high false positive rate and low threshold. RULE OUT.
Western blot characteristics for HIV
Specific, low false positive rate and high threshold. RULE IN.
AIDS diagnosis
1) CD4 below 200
2) HIV positive with AIDS-defining condition
30 CD4+ percentage lower than 14%
problem with ELISA/Western blot
Often falsely negative in first 1-2 months of HIV infection and falsely positive initially in babies born to infected mothers (anti-gp120 crosses placenta).
What is the window period?
Time between acute infection and recovery.
How can you tell AIDS stage based on surface proteins?
as patients enter the symptomatic period and as immune function declines, peoples’ ability to produce any isotype of antibody declines and thus antibodies to capsid antigen (p24) will decline (can’t class switch due to TH deficiency). Once patients develop AIDS in the final stages of the disease, they’re so deficient in T cells that they can’t undergo class switching. IgM can be made in the absence of TH cells, however, and production of IgM continues against envelope glycoproteins (gp120 and gp41) since those antigens are constantly being altered by the process of random mutation (genetic drift).
AIDS virus type
lentivirus (long latent period)
What is reverse transcriptase?
An RNA-dependent DNA polymerase because it synthesizes cDNA from an RNA template.
