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8 Cards in this Set
- Front
- Back
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PATHOGEN
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a microorganism capable of producing pathology in a percentage of normal individuals by avoiding or manipulating the innate immune system
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VIRULENCE
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quantitative measure of pathogenesis
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Infectious Dose 50 (ID 50)
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the dose that will infect 50% of normal individuals;
in lower doses, infection may result without overt disease (subclinical infection) |
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Lethal Dose 50 (LD 50)
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dose required to kill 50% of the test animals
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Determinant of Pathogenesis and Virulence Factors
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components of the pathogen responsible for its ability to cause an infection;
often defined by mutations in virulence genes = lower virulence / ↑ LD50 - virulence genes: exist for the purpose of propagating in the host pathogenesis usually involves numerous determinants of pathogenicity; mutations which result in avirulence often pleiotropic in nature, mapping to a gene involved in reg'n of multiple virulence factors |
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Obligate Pathogens
(Intracellular Obligate Pathogens) |
cannot be found anywhere but in association with its host
can only grow inside of host cells |
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Facultative Pathogens
(Intracellular Facultative Pathogens) |
can grow or survive in the environment as well as in its host
can grow both inside or outside of cells |
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STAGES OF PATHOGENESIS
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* Encounter: breathing, eating, normal body flora
* Entry: lots of body surfaces * Colonization: pili for attachment * Multiplication: become bacteria * Invasion: Type III secretion * Evasion: - avoid being recognized - kill immune cells - live inside immune cells |
