Introduction to Infectious Diseases

Question 1

direct and indirect transmission of infectious diseases

Answer 1

1) direct contact with an affected individual or discharges: airborne, droplet, bloodborne 2) indirect means: vector (animal), famine (inanimate object– virus can live on a doorknob)

Question 2

T/F Infectious diseases make up majority of death in children in the world

Answer 2

true. 64% are due to infectious diseases like malaria, measles, meningitis, pertussis, AIDS, pneumonia

Question 3

most common hospital acquired infections

Answer 3

UTI, pneumonia, and surgical infections. Theres also a breeding ground for antibiotic resistance

Question 4

superbug

Answer 4

highly drug resistant organisms that are created through constant mutation because of our overuse of antibiotics

Question 5

clinical syndrome

Answer 5

the sun of signs of any morbid state, a typical constellation of symptoms, physical findings and diagnostic tests which characterize a primary disease process - a “pattern” of signs and symptoms May be as a result of a number of different underlying primary disease processes (infectious and non-infectious)

Question 6

a clinical syndrome may be systemic or ___

Answer 6

focal: involve a specific organ like hepatitis systemic: many organ systems like influenza like illness

Question 7

infectious causes of hepatitis

Answer 7

viruses (A, B, C) Bacteria (salmonella) Fungi and yeast (Candida) Parasites (malaria)

Question 8

non infectious causes of hepatitis

Answer 8

medications and toxins (acetaminophen, alcohol), autoimmune (lupus) inherited conditions (WD, hemochromatosis) cryptogenic (can’t figure out the cause)

Question 9

contiguous vs hematogenous spread

Answer 9

contiguous: local infection due to breach in natural barriers hematogenous “seeded” from a systemic infection

Question 10

tropism

Answer 10

only certain cells and tissue support the growth of a particular pathogen

Question 11

colonization vs infection

Answer 11

infection: when body site is sterile colonization: when body site isn’t sterile ex/ infection in mouth

Question 12

how does a fever come to be?

Answer 12

1. microorganism releases exogenous pyrogens 2. leukocytes rally but produce endogenous pyrogens 3. hypothalamus releases PGE2 to increase set point. 4. PGEs cause vasoconstriction, shivering, behavioural changes, and increased metabolism which results in fever.

Question 13

example of endogenous and exogenous pyrogens

Answer 13

endogenous: cytokines: ex/ interleukein I, G or TNF alpha can act on the hypothalamus to produce fever via the release of PGE2. exogenous: bacterial endotoxins. they interact with macrophages to activate the cell mediated immune system.

Question 14

cause of rigors during infection

Answer 14

they’re shaking chills. a violent attack of uncontrolled shivering/shaking associated with chills and fever. caused by the effect of PGE2 on peripheral nerves to induce a reflexive shivering phenomena– tense muscles produce heat.

Question 15

4 cardinal signs of local infection

Answer 15

1. warmth 2. erythema 3. edema 4. pain. 5. BONUS: psu. due to dead neutrophils.

Question 16

pathogens that induce pus formation

Answer 16

pyogenic. ex/ streptoccocus pyogenes (strep throat) causes tonsils to become ulcerated.

Question 17

possible infection?

Answer 17

malaria

Question 18

if a person is IgG positive and IgA negative they are likely:

Answer 18

vaccinated or were previosuly infected, but are well now

Question 20

how does Staph aureus permeate into the soft issue/extracellular invasion?

Answer 20

via hyaluronidase (proteases and enzymes allow organism to move deeper into soft tissue)

Question 21

how does listeria infect host?

Answer 21

through intracellular invasion: they survive phagocytosis

Question 22

how does strep pneumo end up causing meningitis?

Answer 22

via dissermination: they pass the innate immune system and get into lymphatics/blood stream and then onto end organ targest.

Question 23

examples of enterotoxin

Answer 23

ehec via shigella toxin

Question 24

how does staph auereus cause toxic shock syndrome?

Answer 24

via exotoxin release of superantigens: causes non-specific stimulation of T cells –> uncontrolled cytokine release.

Question 25

example of an endotoxin

Answer 25

LPS on a cell wall of a gram negative bacteria. can trigger inflammatory response and sepsis but it is inherent to the bacteria– they do not produce it as a toxin.

Question 26

type 1 hypersensitivity reaction (autoimmune response)

Answer 26

anaphylaxis/rash due to IgE response.

Question 27

type II hypersensitivity reponse (immune mediated damage)

Answer 27

apoptosis via cytotoxicity. (ex/ cell necrosis due to Hep B)

Question 28

bacteria-caused Type III immune complexes (autoimmune response to infection)

Answer 28

fever and inflammation: post-streptococcal glomerulonephritis

Question 29

bacteria-caused type IV hypersensitivity immune response (autoimmune response to infection)

Answer 29

delayed type. T cell mediated, causes granulomas or endemic fungii.

Question 30

H. pylori transformation

Answer 30

recall: transformation is the ability for some organisms to favor the development of cancer.

Hpylori is linked to gastric adenocarcinoma

Question 31

How does HIB overtly outsmart the immune system?

Answer 31

Via T cell infeciton– they destroy CD4_ cells.

Question 32

name examples of infections that use capsules to covertly evade the immune system

Answer 32

streptococcus pneumo or pyogenes

haemophilus influenzar

neisseria meningitidis

cryptococcus neoformans

Yes, Some Killer Baceria Have Nice Capsules (yersinia, strep, klebsiella, bacillus, haemophilus, neisseria, cryptococcus neoformans)

Question 33

examples of bacteria that use biofilm production as a method of avoiding the immune system

Answer 33

coagulase negative staphylococci.

Question 34

example of virus that uses antigenic variation to evade the immune system

Answer 34

influenzae. H1N1;H3N2 etc.

Question 35

example of infection that uses mimicry to evade the immune system

Answer 35

shistosoma haemotobium (liver fluke)– coats itself with host antigens to evade the immune repsonse.