Infectious Diseases 1

Question 1

What is a disease?

Answer 1

a disturbance in normal functioning of an organism

Question 2

What is a zoonotic disease

Answer 2

Can be between animals, or between animals are humans, ex. rabies

Question 3

what is pathgensis

Answer 3

the mech. by which a pathgeon causes disease

Question 4

what is an infection

Answer 4

when a pathgoen replicates inside its host

Question 5

difference between symptoms and signs

Answer 5

signs - quantifiable, diarreha, vomitting
symptoms - hard to quantify- headaches

Question 6

primary pathogen vs opportunisitc pathogen

Answer 6

primary- for sure cuased the disease (ex. anthrax will cause disease if you touch it)

opportunisitc- only in the right conditions (ex. HIV in ppl immunodeficient people, candida albicans causes disease under stress)

Question 7

Virulence

Answer 7

intensity of disease

Question 8

Case to infection ratio (CI)

Answer 8

of ppl with the disease/ total infected

Question 9

measles vs. polio

Answer 9

mealess- 95% CI rate
polio- 1% CI rate (paralytic polio)

Question 10

attenauted are good cadidates for?

Answer 10

vaxx dev

Question 11

virulant strains

Answer 11

once caused disease, but don’t anymore

Question 12

Explain the results of the AK mouse study

Answer 12

disease: persinia pestis
question: does AK enzyme contribute to pathogenisis
- mutated proline to serine
- decreased lethality; mutant was virulent
conclusion: AK involved in pathogenesis of yersinia pestis

Question 13

carrier

Answer 13

person infected, but no symptoms

Question 14

Explain the typhoid mary case

Answer 14

example of carrier
- was a cook, infected with salmonella,
- no symptoms herself, kept infecting people through food,
- 50 ppl infected
quarantined for 20yrs, died

Question 15

How do microbes cause disease

Answer 15

entry, evade, nutrients, virulence factors
- virulence factors is differnece between pathgeonic (e.coli), and nonpathogenic (e.coli)

Question 16

How many viurlence factors do e coli, and neisseria goarrhea have respectively?

Answer 16

4, and 3

Question 17

Host range

Answer 17

the group of pathgeons the pathogen can infect

Question 18

bacteria vs. virus entry

Answer 18

bacteria - use something outside the cell
viruses - protein protein interactions

Question 19

Explain host range and how it expands in response to mutations

Answer 19

FPLV first started at only infecting cats,
- mutated inside a fox

• then became CPV in dogs, only infected dogs (causes diarrhea)
• initially, could only infect dogs, but with time and mutations, developed a wider host range
• became CPV2b - infected dogs, cats, wolves, lions

Question 20

What are the 4 virulene factors that bacteria use?

Answer 20

fibronetic binding proteins

fibriae

capsules

special adherence proteins (Tir, Intimin)

Question 21

What is fibronetic binding protein

Answer 21

large glycoproteins in extracell matrix, and plasma of human hosts, fish,etc

bacteria can bind to it

found everywhere, so good for bacteria

Question 22

What are fimbriae

Answer 22

short hair on bacteir cells, sticky
has protein on tips
it attaches to host cell surface receptor

• gram negative, overcomes electronegativity on surface of host
• sticky ends are targetted by immune sys

-bacteria mutate these tipcs quick

Question 23

What are capsules

Answer 23

made of polysaccarides, have polypetides too
- thick layer around bacteria cell
helped avoid immune sys, and stick to host

Question 24

Explain e.coli’s method of evading detection

Answer 24

• entertic e coli is in the nteistine, causes diarrhea in kids
• type 3 secretion system
  -inserts syringe in host, sends tir and intimin through,
  -forms a pedestal, and causes lesions in the membrane of host
  -forms actin polypeptides

Question 25

Explain virulence factors in nessireaie gonorrheaeie

Answer 25

- uses gram negative fibraie to get into cell - endocyotsis, exocytosis - changes fibrae to evade detection - when it dies, its surface is made of lipopolysaccharide, which contain Lipid A - which is toxic to cell - Lipid A causes hole in cell membrane - it continues to replcate, and releases proteases to cut antibodies

Question 26

How do microbes deliver/release virulence facotrs

Answer 26

salmonella - 2 types of type 3 secretion 1. attach using fibraea, inject through syrine 2 molecules (sipA, SopE), induces phagocytosis (they are engulfed and in a capsule type place called the pagosome) 2. second type 3 secrretion, system prevents fusion of phagosome with lysosome - can replicate freely, and exit via exocytosis, apoptosis of host cell - can be phagocytozied by a macrophage, again, they halt the fusion, replicate in phagosome, exocytosis , apoptosis of macrophage

Question 27

Which element do bacteira need to live?

Answer 27

iron

Question 28

4 strategies in which bacteria survive using iron. How do they get iron?

Answer 28

1. siderophore- STEAL (binds strongly to iron-binding proteins in host cell) 2. Bacterial transport proteins - attack to iron binding protein, change conformation 3. make acidic compounds, make pH acidic, iron falls off (needs low PH for binding) 4. hemolysis (degrade mem of RBCs, causes holes, iron comes out through holes

Question 29

Example of an iron-binding protein

Answer 29

TB - uses all 4 mech -symptoms of TB caused by cytokines, made by human host

Question 30

Why was it fashionable to have tb like symptoms

Answer 30

- pale, coughing blood, thought they were visited by vampires, and since it made them thin, it was considered fashionable -the appearance of vulnerability, and weaknesses (50s)

Question 31

How do pathogens evade host defenses?

Answer 31

antigenic variation - shifting thier surface protein structure ex. trypanosuoma brucie - over 1 mill glycoproteins on surface, 1000 glycoproteins on gene - quickly changes variants to evade immune sys