Immunology Exam 6: Infectious Agents Flashcards
Non-treponemal testing methods for Syphilis
RPR, VDRL
Treponemal testing methods for Syphilis
FTA-ABS
TP-PA
T. pallidum Ab for ELISA
T. pallidum Ab by western blot
What is the purpose of the RPR? How to interpret?
Cardiolipin reacts with Reagin (a non-treponemal antibody) to detect syphilis –> Flocculation assay with charcoal agglutination
Reactive = small tiny dots
Non-reactive = one condensed button that looks like a comet tail
Primary stage of Syphilis
Development of a chancre
Secondary stage of Syphilis
Rashes on soles of feet and palms of hands
Latent stage of Syphilis
Non-infectious state that occurs after untreated secondary syphilis, may last for years
More likely to develop into late-stage syphilis than spontaneous recovery
Tertiary (late) syphilis
Appearance of gummas
Neurodegenerative
What are signs of Congenital syphilis?
Hutchisonian Triad –> deafness, keratitis, hutchinson’s teeth
Early to latent infections are _____ antibody positive
IgM
Late or chronic infections are _____ antibody positive
IgG
Non-treponemal antibodies are a _____ test for syphilis
Screening (RH does this backwards)
Treponemal antibodies are a ______ test for syphilis
confirmatory (RH does this backwards)
Cardiolipin
Lipid made from damaged cells, cholesterol, and lecithin that reacts with Reagin (non-treponemal antibodies)
Limitations of TP-PA
Uses serum and CSF only, cannot differentiate between IgM or IgG
In what stages of Syphilis will the RPR/VDRL (non-treponemal tests) be positive?
Primary and secondary
*Starts to decline during latent stage and tertiary stage
*Untreated infections will be better detected than treated infections after latent stage
In what stages of Syphilis will the Treponemal antibody tests be positive? (TP-PA, FTA-ABS, etc)
All stages of Syphilis, with more patients testing positive the later the stage
What is Syphilis treated with?
Penicillin in early stages
Etiology of Lyme’s disease
Transmission of Borrelia burgdorferi by Ixodes ticks
Diagnosis of Lyme’s disease
Bull’s eye rash,
What group of people may be at increased risk of Lyme disease induced arthritis?
People with HLA DRB104 and DRB102
Possible lab diagnosis of Lyme’s
May be grown using Barbour-Stoenner-Kelly medium
Testing includes serum, skin lesions, and CSF for antibody and PCR methodologies
What is the two-step process of Lyme’s disease diagnosis?
Step 1: positive result on EIA or an IFA
Step 2: if signs or symptoms persist for 30 or more days, perform IgG western blot. If signs or symptoms persist for 30 days or less, perform both IgM and IgG western blot
Explain the diagnosis of Lyme’s disease and the western blot
(+) IgM –> must have 2 of 3 characteristic bands
(+) IgG –> must have 5 of 10 characteristic bands
Reverse vs forward algorithm for Syphilis
Forward: start with non-treponemal Ab, then go to treponemal to confirm
Reverse (what RH does): start with treponemal Ab, then do RPR to confirm
