7.4 HOST-MICROORGANISM INTERACTIONS - TRANSMISSION

Question 1

✓Most pathogen are acquired from

Answer 1

external sources

Question 2

Pathogens usually exit the infected patient most frequently from the

Answer 2

respiratory tract and gastrointestinal
tract

Question 3

transmission to the new host usually occurs via

Answer 3

airborne respiratory droplets or fecal contamination of food and water

Question 4

Four (4) important portals of entry for pathogenic organisms

Answer 4

GIT, GUT, respiratory tract, integumentary system

Question 5

Mucous membranes of the GIT, GUT, repiratory tract and conjunctiva

DISEASES

Answer 5

conjunctivitis, trachoma, ophthalmia
neonatorum

Question 6

punctures, injections, bites, cuts, wounds, surgery, and splitting of the skin or mucus membrane due to swelling or drying

Answer 6

✓Parenteral route

Question 7

some organisms have many portals of entry

Answer 7

(Yersinia and B. anthracis)

Question 8

ROUTES OF TRANSMISSION

Answer 8

1. Airborne Transmission
2. Transmission by Food and Water
3. Close Contact
4. Cuts and Bites
5. Arthropods
6. Zoonoses

Question 9

Respiratory Spread
→ common
→aerosolized by coughing, sneezing, and talking

Answer 9

Airborne Transmission

Question 10

—inhalation of infectious particles in liquid droplet dxs

Answer 10

TB,
Brucellosis,
Tularemia,
Legionellosis and
Plague

Question 11

→residue from the evaporation of fluid from larger droplets and are light enough to remain airborne for long periods

Answer 11

Droplet Nuclei

Question 12

→infection occurs via the fecal-oral route

Answer 12

Transmission by Food and Water

Question 13

Transmission by Food and Water spp

Answer 13

Enterotoxigenic E. coli (ETEC)
Vibrio cholera

Question 14

Enterotoxigenic E. coli is the common cause of

Answer 14

TRAVELER’S DIARRHEA

Question 15

→enterotoxin that causes the outpouring of fluid from the cells into the lumen of the intestine

Answer 15

Vibrio cholera

Question 16

Preformed toxins [spp] [fecal oral route]

Answer 16

Clostridium botulinum,
Bacillus cereus, and
S. aureus

Question 17

→passage of organisms by salivary, skin, and genital contact

Answer 17

Close Contact

Question 18

→infection by the mouth flora

Answer 18

Cuts and Bites

Question 19

→dog-bite and cat-bite infections

Answer 19

Pasteurella multocida

Question 20

→tick, flea, or mite bite

Answer 20

Arthropods

Question 21

Arthropods dxs

Answer 21

→relapsing fever,
plague,
Rocky Mountain spotted fever,
Lyme disease,
typhus

Question 22

→depends on contact with animals or animal products
→arthropod vectors (plague), contact with secretions (brucellosis), and contact with animal carcasses and products (tularemia, listeriosis)

Answer 22

Zoonoses

Question 23

Respiratory Tract pathogens

Answer 23

Streptococcus pneumoniae
Neisseria meningitides
Haemophilus influenzae
Mycobacterium tuberculosis
Bordetella pertussis
Salmonella typhi
Salmonella enteric
Vibrio cholera
Brucella spp

Question 24

Streptococcus pneumoniae disease

Answer 24

Pneumonia

Question 25

Neisseria meningitides disease

Answer 25

Meningitis (meningococcemia)

Question 26

Haemophilus influenzae disease

Answer 26

Meningitis

Question 27

Mycobacterium tuberculosis disease

Answer 27

Tuberculosis

Question 28

Bordetella pertussis disease

Answer 28

Pertussis (Whooping cough)

Question 29

Salmonella typhi disease

Answer 29

Typhoid fever

Question 30

Salmonella enteric disease

Answer 30

Salmonellosis

Question 31

Vibrio cholera disease

Answer 31

cholera

Question 32

Brucella spp. disease

Answer 32

Brucellosis (Undulant fever)

Question 33

Skin (Integumentary System), Parenteral pathogens

Answer 33

Clostridium perfringens Rickettsia rickettsii

Question 34

Clostridium perfringens disease

Answer 34

Gas gangrene

Question 35

Rickettsia rickettsii disease

Answer 35

Rocky Mountain Spotted Fever

Question 36

Numbers of Invading Microbes

Answer 36

✓ID50 ✓LD50

Question 37

→compare relative virulence under experimental conditions; it is not an absolute value

Answer 37

✓ID50 (Infectious Dose for 50% of a sample population)

Question 38

→potency of a toxin

Answer 38

✓LD50 (Lethal Dose for 50% of a sample population)

Question 39

✓ID50 B. anthracis Cutaneous

Answer 39

10-50 endospores

Question 40

✓ID50 B. anthracis Inhalation

Answer 40

10k-20k endospores

Question 41

✓ID50 B. anthracis Gastrointestinal

Answer 41

250k-1M endospores

Question 42

✓ID50 V. cholerae

Answer 42

108 cells (decreased upon neutralization of stomach acidity or administration of bicarbonates)

Question 43

LD50 Botulinum toxin

Answer 43

0.03 ng/kg

Question 44

LD50 Shiga toxin

Answer 44

250 ng/kg

Question 45

LD50 Staphylococcal enterotoxin

Answer 45

1350 ng/kg

Question 46

Host-microorganism interactions path

Answer 46

Encounter and entry Colonization and entry Invasion and dissemination Outcome

Question 47

Corresponding infection-disease stages

Answer 47

Incubation stage Prodromal stage Clinical stage Stage of decline Convalescent stage

Question 48

Pathogen encounters and colonizes host surface

Answer 48

Encounter and entry

Question 49

Pathogen multiplies and breaches host surface defenses

Answer 49

Colonization and entry

Question 50

Pathogen invades deeper tissues and disseminates, encounters inflammatory and immune responses

Answer 50

Invasion and dissemination

Question 51

Pathogen completes cycle by [outcomes]

Answer 51

Leaves host Destroys host Remains in latent state Is destroyed by host

Question 52

[stage] No signs or symptoms

Answer 52

Incubation stage

Question 53

[stage] First signs and symptoms, pathogen may be highly communicable

Answer 53

Prodromal stage

Question 54

[stage] Peak of characteristic signs and symptoms of infection or disease

Answer 54

Clinical stage

Question 55

[stage] Condition of host deteriorates possibly to death or signs and symptoms begin to subside as host condition improves

Answer 55

Stage of decline

Question 56

[stage] Full recovery of surviving host or chronic infection develops, or death

Answer 56

Convalescent stage