Course of Infectious Disease

Question 1

what are Koch’s Postulates?

Answer 1

1. pathogen must be present in all diseased individuals but not healthy
   (normal flora can carry pathogens)
2. pathogen must be isolated ad grown in pure culture
   (some are infected by asymptomatic)
3. cultured pathogen should cause disease in healthy host
   (colonization does not equal illness)
4. pathogen must be re-isolated from the infected host
   (TRUE)

Question 2

what are the 5 stages of disease?

Answer 2

1. incubation
   - no symtoms
   - most transmissible
2. prodromal
   - non specific symptoms
   - fever, malaise
3. illness
   - peak symptoms
   - pathognomic signs
4. decline
   -symptoms improve
5. convalescence
   - recovery
   - still possibly contagious

Question 3

what are the 3 types of infection?

Answer 3

1. acute
   - rapid onset
   - short duration
   - ex. flu
2. chronic
   - slow onset
   - long duration
   - ex. TB, HIV
3. latent
   - no symptoms
   - potential reactivation
   - ex. herpes

Question 4

what are the 3 stages of HIV?

Answer 4

1. acute
   - flu like symptoms
   - CD4+ attack
2. chronic
   - slow immune decline
   - mild/asymptomatic
3. AIDS
   - < 200 CD4+ T cells
   - severe infections (TB, pneumonia)

Question 5

what is carrier state?

Answer 5

harbour pathogen without symptoms

still contagious

Question 6

what are some examples of carrier states?

Answer 6

Mary mallon (salmonella typhi)

HSV 1 and 2

chlamidyia

Question 7

what are some causes of emerging infectious diseases? provide an example of a disease.

Answer 7

AIDS
travel
antibiotics
climate change
animal contact

bird flu
- risk increases with human-human transmission

Question 8

what are the 3 types of reservoirs?

Answer 8

1.human
- symptomatic
- asymptomatic carriers (high risk)

2. animals
   - direct (rabies, Lyme disease)
   - indirect (salmonella from poultry)
3. non-living
   - surfaces
   - food
   - water
   - soil

Question 9

what are the 4 modes of transmission?

Answer 9

1. direct contact
   - hands
   - body fluids
   - needle sticks
2. indirect contact
   - medical equipment
   - fomites (doorknobs)
3. droplet (< 1m)
   - flu
   - norovirus
4. airborne (> 1 m)
   - TB
   - measles

Question 10

what are the precautions for droplet infections?

Answer 10

individual room
mask (within 2m of pt)
goggles (within 2 m of pt)
may require gown and gloves
door can be open

Question 11

what are the precautions for airborne infections?

Answer 11

negative pressure room
N95 mask
goggles
anteroom
door always closed

Question 12

what are the precautions for contact infection?

Answer 12

individual room
individual equipment
gown
gloves
mask (if ARI)

Question 13

what are the 3 types of mosquitoes (vector-borne transmission)?

Answer 13

1. culex
   - west nile
   - bites dusk/dawn
2. anopheles
   - malaria
3. aedes
   - dengue
   - zika
   -chikungunya
   - bites during the day

Question 14

what are the 3 interventions for infectious disease?

Answer 14

1. identify mode of transmission
2. undersand pathogenic properties
   - infectious dose
   - stability
3. control spread
   - climate
   - elimination