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12 Cards in this Set
- Front
- Back
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Parasite
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an organism smaller and less highly differentiated that its host, living at the expense of the hose
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Infection
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Habitation of host by a parasite
It does not indicate disease |
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The Host-Parasite rules
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Darwinian selection puts pressure on both host and parasite
Both Host and parasite live only to perpetuate their own species, which leads to co-evolution As the host becomes more sophisticated, so does its parasites They evolve toward mutual benefit and co-existence There is species and tissue specificity Infection occurs (but not disease) Number of parasites is greater than the host Coevolution leads to parasitic degeneration |
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Parasitic degeneration
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As there is coevolution, the parasites lose DNA coding sequences because host takes care of all their needs
Ex: Virus |
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Disease
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Violates the Host-Parasite Rules
Disease and epidemics are accidents Most infections are subclinical Infection is the rule, disease is the exception |
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Species jumping
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When the parasite jumps from its indigenous host to a new host in which is has to start the evolutionary process over again
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Indigenous Biota
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Parasite has co-evolved with its host and underwent parasitic degeneration
It has become essential for our survival/ well-being |
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How much of our body is comprised of bacteria?
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10% of our dry weight are bacteria
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Where do most indigenous biota reside?
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In intestines
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What is the beneficial role of Indigenous biota
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First line of defense in excluding pathogens
Stimulate cross-reactive antibodies Contribute to nutrition of the host Influence organ development |
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What are the harmful effects of indigenous biota
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Initiate endogenous diseases
Potentiate effect of exogenous pathogens Retard growth rate of host Deadly in wrong tissue compartment |
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Vertical transmission
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In order to assure survival of the next generation, mother transmits her indigenous biota to offspring
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