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16 Cards in this Set
- Front
- Back
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What did Fracastoro do?
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Fracastoro was among the first to develop the concept of contagion. Infection is transmitted through transmissions of particles from one person to another. He was the first to enunciate the idea of contaminated particles passing on infection.
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What did Semmelweis do?
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Made everyone wash their hands
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What are the Henle-Koch Postulates for? What are they?
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The Henle-Koch postulates are what need to be satisfied to prove that an organism causes a disease. It is not always possible to establish an animal model of infection, so for ever disease you cannot establish these principles as well as you would hope.
-The organism is regularly found in the lesions of the disease -It can be isolated in pure culture on artificial media -Inoculation of the pure culture into a susceptible animal reproduces the disease -The organism can be recovered from the lesions in the infected animal |
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What is a pathogen? Primary pathogen? Opportunistic pathogen?
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Any microorganism that is capable of causing disease in a susceptible host
Primary pathogens can cause disease regardless of the health of the host. Opportunistic pathogens don’t generally cause infections unless they are given an opportunity. |
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What is colonization?
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Establishment of the ecological niche for an organism, survival and replication without actual tissue invasion
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What is an infection?
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The ability of an organism to invade tissue, replicate, and stimulate an immune response.
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What is intoxication?
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Agents that cause disease by elaboration of toxin sometimes without the presence of bacteria
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What is virulence?
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The severity of the disease caused by the agent
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What is a virulence determinant?
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A bacterial component or product that contributes to the ability of a pathogen to cause disease
-May be chromosomal or on movable genetic elements such as plasmids, transposons, or phages |
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What is the iceberg model of infection?
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In many infections, >90% are asymptomatic
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What are the categories or stage of human infection?
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Asymptomatic
Active: subject with overt disease Incubatory: Subject incubating but without symptoms of disease Latent: Pathogen persists in tissue without symptoms for much of the time |
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What are the host factors that increase susceptibility to infection?
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-Extremes of Age
-Malnutrition -Genetic defects in immunity -Acquired defects in immunity -Medical diseases: diabetes, liver disease -Chemotherapy, immunosuppresive agents -Implantation of prosthetic material -Organ transplantation |
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What is horizontal transmission?
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Transmission by direct physical contact or an infected water supply
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What is vertical transmission?
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From mother to child, one generation to the next
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What is the sequence of steps necessary for the establishment of infection?
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1. Adherence and colonization of host surfaces
2. Evasion of host defense mechanisms such as phagocytosis or intracellular killing 3. Adaptation to the hist environment, ability to undergo change such as antigenic variation -Invasion of tissue both locally or systemically (dissemination) -Host response- often responsible for tissue damage |
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What are some strategies used by pathogens to cause respiratory tract infections?
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-Target specific cellular receptors for adherence
-Interference or evasion of clearance mechanisms -Evasion of phagocytosis -Evade destruction by alveolar macrophages |
