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What is pathogenicity in comparison to virulence?
Pathogenicity is a pathogens ability to cause disease and virulence is the extent/degree of pathogenicity
What are 3 portals of entry
mucous membranes, skin, parenteral route
Many organisms gain entry through the mucous membranes, gives examples of mucosal portals of entry
conjunctiva, respiratory tracts, GI tracts, GU tracts
Most organisms cannot penetrate intact skin; how then would pathogens enter a host through this portal of entry
they would enter through the hair follicles and sweat glands on the skin
How and where do pathogens enter the body through the parenteral portal of entry?
they enter in breaks in the skin and mucous membranes; bites, injections and wounds
What function do capsules and M proteins have in common?
They both add to the bacteria's virulence by preventing phagocytosis (M-proteins and capsules are both heat resistant and acid resistant)
Would you expect a bacterium to make coagulase and kinase simultaneously?
No, coagulase are bacterial enzymes that coagulate the fibrinogen in blood and convert it into fibrin and kinase breaks down fibrin.
Why does the influenza vaccine only offer a few months of protection?
antigenic variation; influenza alters its surface antigens so antibodies formed from the previous vaccination do not bind to the new antigens.
Define LD50 and ID50
ID50-Infectious dose for 50% of a sample population; LD50-Lethal dose for 50% of a sample population.
How does E. Coli cause membrane ruffling?
E. Coli releases invasins which alters the host's actin and form ruffling due the the disruption of the cytoskeleton.
What are 6 ways that a pathogen avoids phagocytosis?
M protien, capsules, ability to survive in phagolysosome, opa protien, mycolic acids, biofilms, antigenic variation, inhibit adherance
How would you define cytopathic effects of viruses?
Cytopathic effects are visible signs in a host cell of a viral infection
What are ways viruses cause cytopathic effects in the cell?
stop cell synthesis, cause cell to release lysosomes, create inclusion bodies, fusing cells to create syncytium, chromosomal changes, loss of contact inhibition
Name one virulence factor for fungal, protozoan, helminthic, and algal disease
Fungi: toxins, mycotoxins Protozoan:digesting tissues antigenic variation Helminths: Waste products, size Algae: neurotoxins
proteins produced and secreted by bacteria; soluble in body fluids; gram (+) or (-); can be converted to toxoids; usually effects cell functions; usually destroyed by heat
exotoxins
A-B toxins; membrane-disrupting toxins (leukocidins, hemolysins, streptolysins), genotoxins, superantigens are all endotoxins or exotoxins?
exotoxins
