Med Micro 1.1 Flashcards
How does HPV enter the cell?
Receptor mediated endocytosis (common for animal viruses)
In what way s are Koch’s postulates alive and well today? Or are they?
Goal is to establish cause of a disease. Often can’t use animal model due to specificity. Hard to use: isolate bacteria; some diseases caused by many pathogens; can’t inject a human. Use epidemiology.
Epidemiology
Take data from people who have a disease and use this to study a pathogen. ex HIV
Examples of use of Koch’s postulates
HIV, HPV - still used. Unintentional exposure satisfies Koch’s 3rd postulate.
Pathogenesis
steps involved in development of disease
Pathogenicity
ability to cause disease
Pathogen
microorganism capable of causing disease
Pathology
study of structural and functional manifestations of disease
Infectious Disease
diseases caused by microbe and microbes that cause infectious disease are collectively referred to as pathogens
Infection
colonization by a pathogen
Infection vs infectious disease
Disease is an imbalance, displaying symptoms. Infections strictly speaking aren’t imbalances
Virulence factors
Factors that help a virus attach and then cause disease
Fimbrae
used for attachment. contain adhesins.
Why haven’t we been able to eliminate microbes?
We change (immune response), microbes change (selected for).
4 factors that can alter the host-parasite relationship
Stress/lack of sleep; drugs; age; genetics
Hospitals and infectious disease
Infections result from healthcare professionals not washing hands; also the location of overuse of antibiotics so much resistance generated there
Mechanisms of Pathogenicity (parts of infectious disease)
Portals of entry, Penetration or evasion, damage to host cells, portals of exit
Portals of entry
Mucous membranes (respiratory, GI tract, genitourinary tract, conjunctiva), skin, parenteral route (injury bypasses normal defense)
Factors leading to infection
Number of microbes, adherence
Penetration or evasion factors
Penetration is actual entry to actually get into the host. Capsules, cell wall components, enzymes, antigenic variation, invasins, intracellular growth
Damage to host cells caused by…
Siderophores (collect iron, needed for enzymes), direct damage, toxins (exo and endo), lysogenic conversion (ie gene from virus into bacteria), cytopathic effects
Portals of exit
Generally the same as entry. Why? Similar environment (binding)
How have we evolved to deal with such a high level of diversity?
Look at general mechanisms - innate immunity, then adaptive response
Koch’s postulates
Present in all cases, isolate it, able to infect healthy host, and reisolate from new host
