Infectious Disease Flashcards
What are the three outcomes of an organism entering the body?
Entry, cleared and NO INFECTION.
Entry, multiply without tissue damage get INFECTION.
Entry, multiply, tissue damage, get INFECTIOUS DISEASE.
What is infectivity?
Ability of an infectious agent to multiply.
What is pathogenicity?
Ability of an infectious agent to cause disease.
Compare pathogenicity to infectivity.
Pathogenicity-Can it cause disease?
Infectivity-Can it multiply?
What are the steps of infection?
- Enter the body. Can do so through lot’s of different ways, but you have to bypass the body’s natural barriers.
- Multiply locally.
- Spread-along the path of least resistance such as along tissue planes, lymphatics, blood.
- Set up focus of infection at distant site.
Acute infectious state
Short term infection with symptoms. Days to weeks.
Chronic infectious states.
Long-term active infection with symptoms. Weeks to years.
Subclinical infectious states.
Infection detectable by tests only.
Latent infectious state
No active growth or organisms, but can reactivate (TB, chickenpox, HIV)
Carrier
Active growth of organisms with or without symptoms.
What is a culture and what is it used for?
Isolation of the pathogen. Bacterial infections.
How does serology work and what type of infections is it used for?
Detecting pathogen specific antibodies in the serum. Bacterial, viral and fungal.
What are Nucleic-acid based tests and what are they used for?
Molecular diagnostics. PCR, transcription mediated amplification, nucleic acid hybridization, etc. Viral and fungal.
Gross inspection vs. Microscopic inspection
Both are observation of organisms/pathologic changes in tissue or other clinical samples.
Gross-resected or autopsy organs.
Microscopic-biopsy or fluids.
What is H&E Staining?
Direct observation of agents or products in hematoxylin and eosin staining. Acid vs. bases.
What does Gram stain identify?
Most bacteria, some yeast
What does acid-fast stain?
Mycobacteria and nocardia.
What does silver stain?
Fungi, legionella and pneumocystis.
What does Mucicarmine stain?
Cryptococci.
What does giemsa stain?
Campylobacteria, helicobacter, leishmaniae, malaria.
What are specific antibody probes.
Raise an antibody against the target. Becomes a colored tag. Used against all classes and common in cancers.
What do special stains do?
Identify organisms on the basis of particular characteristics of their cell wall or coat.
How does host response induce damage?
Immune mechanisms of host result in tissue damage. Our immune response is responsible for most of our symptoms.
What are the mechanisms of damage of enzymes?
Tissue destruction, vascular damage, ischemic injury.
What type of inflammation doe lymphomononuclear and granulomatous fall under?
Chronic.
What causes the cytopathic/proliferative tissue response?
Virus.
What causes necrosis predominant?
WARTS. Clostridium perfringes.
What is cytopathic/cytoproliferative inflammatory response characterized by?
Cell necrosis and/or cellular proliferation. Inflammatory cells are sparse.
Viral inclusions
Aggregation of viral material
Multinucleated cells
Fusion of host cells
What is infective endocarditis?
A serious infection of the heart valves and endocardium caused by bacteria.
(Prescribe prophylatic antibiotics to patients with valve problems.)
What are vegetations?
Globs of material formed by infective endocarditis. Composed of organisms and bits of clot that sit on the heart valve and destroy the underlying cardiac tissues.