quiz 10 Flashcards
Why is it important to identify an infectious agent?
To know how to treat it.
To track its spread.
To monitor its evolution.
To understand its symptoms or complications.
What is checked in sterile vs. non-sterile sites during sample collection?
Sterile sites: Check for any microbial presence.
Non-sterile sites: Look for unusual microbial growth.
What is 16s rRNA PCR used for?
To identify bacterial species based on a conserved ribosomal subunit sequence common across genera.
What are the biosafety levels and their characteristics?
BSL-1: Not known to cause disease.
BSL-2: Moderate hazard, may cause disease.
BSL-3: May cause disease via inhalation.
BSL-4: Dangerous pathogens.
What are common pathogen identification methods?
Staining.
Biochemical tests (e.g., lactose fermentation).
Mass spectrometry (protein profiling).
Nucleic acid assays (PCR, qRT-PCR).
What are the advantages of biochemical tests?
Provide information on bacterial metabolism.
Can differentiate species within a genus.
What are the advantages of PCR for pathogen identification?
16s rRNA sequences are known for most bacteria.
Faster than biochemical tests.
Detects specific virulence genes.
qRT-PCR: Detects viral RNA by converting it to cDNA, then amplifying dsDNA.
How many toxin genes does Clostridium botulinum have, and which are pathogenic?
7 toxin genes (A-G); A, B, E, and F are pathogenic.
How do immunological methods detect pathogens?
Use antibodies to bind pathogen structures or secreted toxins.
Antibody binding indicates the presence of an antigen.
What are common immunological tests and their characteristics?
ELISA: Quantitative plate-based assay.
Immunofluorescence: Qualitative detection.
Immunochromatography: Rapid detection tests.
Define sensitivity and specificity in the context of immunological tests.
Sensitivity: Lower detection limit.
Specificity: Accuracy in detecting the correct antigen.
Define endemic, epidemic, and pandemic.
Endemic: Low level of disease in a population at all times.
Epidemic: Sudden spike in cases in a population.
Pandemic: Spike in cases over a large geographical area.
What is the difference between incidence and prevalence?
Incidence: Number of newly diagnosed cases (reflects disease risk).
Prevalence: Number of active cases at a given time (reflects disease duration).
What is the reproduction number (R0) vs. the effective reproduction number (R)?
R0: Average number of people infected by one individual in a fully susceptible population.
Example: At the start of COVID.
R: Same as R0, but in a population with partial immunity.
Example: Current COVID situation.
If R > 1, the epidemic grows; if R < 1, it eventually stops.
