biot3ch31

2 organisms living together in varoious relationships

• one benefits, neither harmed
• both benefit
• one benefits, other harmed

host where parasite gains sexual maturity

organism infected with a parasite that also infects humans

any parasitic organism that causes infectious disease

• primary causes disease by direct interaction with healthy host
• opportunistic is part of normal flora and caueses disease when it gains access to a place it shoudn't be 

ability of a parasite to cause disease

ability to trigger exaggerated immune responses

• # of organisms
• degree of virulence of pathogen
• host's defense

• infectivity- ability to esablish focal point of infection
• invasiveness - ability to spread to adjacent tissues
• pathogenic potential - degree to which pathogen can damage host

• number of pathogens that kill 50% of a group of hosts in a specified time
• same but infect not kill

actively penetrate host's mucous membranes or skin or passivly penetrate through wounds or opening in skin

producing specific products or enzymes

viable bacteria in blood

bacteria or their toxins in blood

bacteria that are able to grow and multiply in various cells of a host

can live within host cells and in the outside environment

can't grow/multiply outside of a host

increase virulence is coded in large segments of DNA that carry virulence genes which alllows for things like e. coli to inject virulence proteins into cytoplasm of eucaryotics hosts

disease that result from a specific toxin produced by bacteria

condition caused by toxins in the blood of host

specific substance that damages host

• usually released as the pathogen grows
• a soluble protein
• travels to other tissues to where it causes damge
• cause antibody produciton (can be bad_

• A subunit is repsonsible for toxic effect
• B subunit binds to target cell

produce and extrmeem immune respononse from the host

target intestinal mucosa

target generall tissues

membrane distrupting exotoxin that can cause hemolytic reactions and kill the cell

beta is complete lysis and alpha is partial

remove charged head groups from phospholipids in host cell plasma membranes which destabilizes the membrane so the cell lyses and dies

• toxins bound to bacterium
• released when organism lyses
• lipid A toxic component
• weaker than exotoxins

• fever
• shock
• blood cogulations
• weakness
• diarrhea
• (all effects are indirect)

• limiting bacteria entry while still remaining functional
• i.e. skin, mucocus membranes with cillia, ph reg

• soluble anti-microbial producst
• host blood and other body fluids contain anti-microbials

• have mechanisms to resist:
• complement system
• phagocytosis
• specific immune responses