THE BASICS

Question 1

Differentiate between mortality and morbidity

Answer 1

Mortality = death/amount of deaths

Morbidity = all other side effects besides death (social, economical, physical illness)

Question 2

What gives “The Black Plague” its name?

Answer 2

The bacteria Yersinia pestis causes the extremities of the body to turn black

Question 3

What is a symptom of Syphilis

Answer 3

Ulcers around the face and mouth

Question 4

What does the Miasma Theory of disease state?

Answer 4

Miasma, or bad air caused diseases.

Question 5

What does the Contagion Theory of disease state?

Answer 5

Contagions, or seeds of cantgiousness were spread across a community. *This theory was supported heavily with superstition.

Question 6

What does the Humoral Theory of disease state?

Answer 6

Disease is caused by an imbalance of the 4 humors

Question 7

What revolutionary concept was determined by the Germ Theory?

Answer 7

That some diseases are caused by the transmission of a microorganism. Preventing the spread of this microorganism would reduce the transmission of disease.

Question 8

Briefly explain Koch’s Postulate

Answer 8

1. Identify an infectious disease
2. Compare bacteria colonies of unhealthy and healthy subjects
3. Isolate the microorganism that causes infection
4. Confirm hypothesis by inoculating the microorganism into healthy subject - it should become unhealthy.
5. The same microorganism should be extracted from secondary subject.

Question 9

Modern Koch’s Postulate suggests that a 6th step should be added; treating unhealthy subjects with antibiotics to confirm microorganism presence. Why might this be problematic?

Answer 9

There many not be an antibiotic available to kill the microorganism.

Question 10

What are some limitations of Koch’s Postulate?

Answer 10

• Microorganisms can not be grown on the plate
• Susceptibility to infection can differ due to genetics
• Pathogenic bacteria can lose their virulence when cultured outside the host

Question 11

What limitation does Penicillin raise when treating diseases? Why is this so?

Answer 11

Penicillin is only effective on Gram Positive pathogens. The penicillin targets peptidoglycan synthesis, and the peptidoglycan is exposed in Gram Positive bacteria only.

Question 12

What are 3 pathogens that can be treated with penicillin? What do they all have in common?

Answer 12

Staphylococcus, Streptococcus, Bacillus diphteriae

They all are gram positive

Question 13

Differentiate between the definitions of disease and infection

Answer 13

Disease is damage to the host, where symptoms will manifest

Infection is the successful colonization of the host, with the possibility of causing damage to the body (disease)

Question 14

True or False: Colonization always leads to disease

Answer 14

False, colonization just means that the microorganism can grow in/on the host - it is not necessarily bad.

Question 15

What allows pathogens to infect hosts with a higher success rate?

Answer 15

Virulence factors

Question 16

What does an opportunist pathogen rely on? Why?

Answer 16

Opportunists rely on the weak immune systems of their hosts (babies, the elderly etc.) because their virulence properties/factors are not high.

Question 17

When is an infection considered an infectious disease?

Answer 17

When the colonization of the pathogen becomes harmful to the host.

Question 18

What is zoonosis?

Answer 18

A non-pathogenic infection for animals that becomes pathogenic when manifested in humans.

Question 19

Why is zoonosis a thing, considering humans and animals have very similar features?

Answer 19

The protein interactions between animals, humans and the virulence factors of the bacteria cause different outcomes; some pathogenic and others commensal

Question 20

What is a mutualistic relationship between bacteria and host?

Answer 20

The bacteria benefits from colonizing in the host as it gains nutrients, but the host also benefits as the bacteria provides a service to optimize growth (ie. bacteria will help digest undigestible material, bacteria will protect the host).

Question 21

What is an asymptomatic relationship between bacteria and host?

Answer 21

The bacteria colonizes the host without initiating damage to the host.

Question 22

What is a pathogenic relationship between bacteria and host?

Answer 22

The bacteria uses the host as nutrients for growth and obtains such nutrients by damaging the host. The bacteria will specifically develop virulence factors to improve its damage strategy.

Question 23

What is an example of a pathogenic relationship?

Answer 23

Staphylococcus has increased its virulence factors to get better at infecting humans

Question 24

What is an example of a commensal-relationship?

Answer 24

Salmonella has reduced its virulence factors over time to obtain equilibrium with the host, so that it colonizes without damage.

Question 25

What is an example of a niche-driven relationship?

Answer 25

A bacterial pathogen may infect an animal and act as a commensal, but once it leaves it niche (animal) and enters a human it becomes pathogenic.

Question 26

What is an example of a genetic trait that can be used to help commensals and pathogens? Explain how.

Answer 26

Fimbriae are finger-like protrusions found in the intestinal tract.
- In commensals they are useful for bacteria to attach and remain in the intestinal tract.
- In pathogens they are useful for feeding deeper into the tract and infecting the blood stream of the host.

Question 27

True or False; only one virulence factor is needed by pathogens to successfully harm the host

Answer 27

False, virulence factors work together to target the host

Question 28

Why do some pathogens have virulence factors that reduce its own virulence?

Answer 28

In order to take full advantage of the host the pathogen will slowly harm the host an collect as much nutrients as it can. Once it is fully developed it will let its severe virulence factors damage the host entirely.

Question 29

Distinguish between disease and infection in relation to transmission and contact.

Answer 29

• In some cases, infections require a single exposure to the pathogen in order for disease to be manifested. Diseases do not require exposure.
• Infections are eradicated when transmission is cut. Diseases do not depend on exposure.
• Changes in behavior of a large group of people (ie. social distancing) can reduce transmission of infection. In some diseases, no matter what the behavior of the masses, it will still remain.

Question 30

What are bacterial pathogens as explained by the DRF (damage response framework)?

Answer 30

Pathogens that cause disease to ANY host. There is no preference to who the disease will manifest in.

Question 31

What are opportunistic pathogens as explained by the DRF?

Answer 31

Pathogens that only target hosts with weak immune systems.

Question 32

What are emerging pathogens as explained by the DRF?

Answer 32

Pathogens that are caused by a changing environment.

Question 33

What are some conditions (3) that trigger of emerging pathogens?

Answer 33

1. Modern technologies that allow for prolonged life expectancy create a larger pool for opportunistic pathogens.
2. Updated virulence factors in bacteria that were commensals or had weak virulence factors.
3. New human behaviors that trigger the growth of pathogens (water systems, mass food production)