2 - Virulence factor - characteristic that enables bacteria...

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Virulence Factors Virulence factor - characteristic that enables bacteria to cause disease - may be common to all bacteria, or a specific genus, species or pathogenic strain - genus or species specific virulence factors provide a survival advantage - strain specific virulence factors are usually acquired through mechanisms of genetic exchange and do not confer a survival advantage Pathogenesis - mechanism or route by which a microbe causes disease - the greater the number of virulence factors, the more pathogenic the organism - pathogenecity is qualitative; virulence is quantitative Definitions Pathogen: any microorganism capable of causing disease Infection: persistence on or within another living organism Disease: end product (damage) resulting from an infectious process Opportunist: an organism that does not normally cause a disease but can become pathogenic under certain circumstances Incubation: time from infection to onset of symptoms / disease Routes of Transmission Horizontal transmission: • Direct contact (secretions, blood, etc.) • Respiratory (aerosol) • Contaminated inanimate objects (fomites) • Insect vector (mosquitoes, ticks, flies) Vertical transmission: • mother to fetus STEPS IN INFECTION Number of invading microbes
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This note was uploaded on 05/09/2010 for the course LMP 232 taught by Professor Crandall during the Spring '10 term at University of Toronto- Toronto.

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2 - Virulence factor - characteristic that enables bacteria...

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