Medical Microbiology And Epidemiology

Question 1

Define Pathology

Answer 1

• study of disease

- refers to the disease “process” of a particular pathogen

Question 2

Define Etiology

Answer 2

• studies of the causes of disease

- refers to a specific cause

Question 3

Define Pathogenesis

Answer 3

• development of disease

- refers to all the processes of damage that a microbe does when it establishes an infection

Question 4

Define case

Answer 4

• a person with a specific infection
  
  • can be obvious (Frank Case)
  • not obvious: carrier

Question 5

Define carrier

Answer 5

• a person who doesn’t know they have an infection
  
  • asymptomatic
  • subclinical

Question 6

Define reservoir

Answer 6

• where you expect to find a particular microbes (source)
  
  • Specialists (people)
  • zooonotic (animals)
  • environment (soil)

Question 7

What are portals of entry? Examples?

Answer 7

• ways a pathogen can enter a body
  
  • Respiratory tract (inhalation)
  • gastrointestinal tract (ingestion, sexual)
  • urinary tract (urethra)
  • reproductive system (sexual)
  • skin (wounds, bites)
  • direct contact with mucosa or compromised skin

Question 8

What are portals of exit? Examples?

Answer 8

• How a pathogen gets out of the body
  
  • respiratory secretions
  • gi tract (fecal matter)
  • blood transfusions
  • urogenital tract

Question 9

What is a communicable disease?

Answer 9

• infectious diseases where person to person transmission is possible
  
  • some are easy to transmits (in casual contact)

Question 10

What does contagious mean in terms of transmission

Answer 10

-easy to transmit from person to person

Question 11

What are non communicable diseases

Answer 11

-come fro microflora (displaced microbes) or from environmental reservoir or from zoonotic pathogens

Question 12

What some examples of vehicles? (3)

Answer 12

• water
• food
• air

Question 13

What are fomites?

Answer 13

• inanimate objects that can carry a pathogen

- Examples-latches in a bathroom, stehscopes

Question 14

Types of direct transmittion

Answer 14

• contact: kissing, sex
• droplets: colds, chickenpox
• vertical: HIV syphillis

Question 15

Types of indirect transmission (3)

Answer 15

• formites
• food, water, biological products
• air

Question 16

What are vectors?

Answer 16

• invertebrates animals that can carry pathogens from one host to another
  
  • tick bite

Question 17

What is an infectious dose (ID)?

Answer 17

• # of microbes to establish an infection

- ID 50: dose the infects 50% of lab animals

Question 18

Describe how high/low IDs effect how infectious it is

Answer 18

• Lower ID: more infectious/virulent

- higher ID: less infectious

Question 19

What is the most infectious virus?

Answer 19

Measles: takes 1 virion to be infectious

Question 20

What is the chain of infection?

Answer 20

Organism > Reservoir > transmission > susceptible host

Question 21

What is morbidity?

Answer 21

-disease/ illness

Question 22

What does incidence refer to?

Answer 22

• new cases

- time/100000

Question 23

Define prevalence

Answer 23

-# of existing cases

Question 24

What are the measures of morbidity?

Answer 24

-incidence > prevalence

Question 25

Define remission

Answer 25

- disease is “on hold” - patient has recovered, but pathogen is still present and can cause future relapse -common in viral infections that go latent in the body, then reactivate when host undergoes changes in the body (weak immune system, stress etc)

Question 26

What is seroprevalence?

Answer 26

- rate of positive antibody test in a population vs a pathogen - detects active cases + recovered cases (latent too)

Question 27

Endemic

Answer 27

-Where you expect to find the pathogen/disease

Question 28

Define Sporadic (occurrence)

Answer 28

- diseases that pop up randomly | - timing is inconsistent

Question 29

What is an outbreak?

Answer 29

- sharp increase in cases | - limited to one geographic area

Question 30

What is an epidemic?

Answer 30

-more cases that is not limited to one geographic location

Question 31

Define Pandemic

Answer 31

- when an epidemic crosses one continent to another | - rapid increase in cases in multiple continents

Question 32

Define Latency

Answer 32

-when a person seems to have recovered, but the pathogen is still in the body

Question 33

What is a chronic carrier?

Answer 33

-a person who is either recovered or has mild symptoms but continue to transmit the pathogen

Question 34

Define sequelae

Answer 34

-long term consequences that persist after recovery because of the damage done during the infection

Question 35

What are nosocomial infections?

Answer 35

- aka healthcare associated infections | - infections that people get after they have been admitted in a healthcare facility

Question 36

What are the most common types of nosocomial infections? (3)

Answer 36

- urinary tract (40%): Ecoli, P. Aeruginosa - lower respiratory tracts (18%): S. Aureus, P. Aeruginosa - surgical wounds (17%): Ecoli, P. Aeruginosa

Question 37

What are the causes of Nosocomial infections (healthcare associated infections)? (3)

Answer 37

- microorganisms in healthcare associated environment - chain of transmission (healthcare workers, fomites) - compromised host