Chapter 15: epidemiology and nosocomial infections

Question 1

Epidemiology

Answer 1

Study of frequency and spread of disease

Question 2

Etiology

Answer 2

Study of the cause of disease

Question 3

Incidence

Answer 3

Number of new cases in a population in a time period

Question 4

Prevalence

Answer 4

Total number of cases (old and new) in the population in a time period
- provides info about severity of outbreak

Question 5

Endemic

Answer 5

Disease is present at low level all the time with no public health threat
- ex: chicken pox in US

Question 6

Epidemic

Answer 6

Sudden higher than normal incidence of a specific disease

Question 7

Pandemic

Answer 7

Worldwide epidemic, random, unpredictable disease pattern

Question 8

Reservoirs of infection

Answer 8

Site where pathogen can persist and maintain ability to infect

Question 9

Human carrier

Answer 9

Sick person who has recovered from a disease but still harbors the gene
- ex: Typhoid Mary

Question 10

Zoonoses

Answer 10

Animals that can carry disease (Arthropoda, vertebrates)

- ex: rabies from a dog

Question 11

Non-living disease carriers

Answer 11

Water, soil

Question 12

Portals of entry

Answer 12

Pathogen must get from reservoir to person through portal of entry

• skin: broken skin, follicles
• mucus membrane: urinary tract, anus, eyes, ears, nose, placenta
• parenteral sites (injured tissue)

Question 13

Portals of exit

Answer 13

• feces
• body fluids
• skin flakes

Question 14

Challenges in controlling transmission

Answer 14

Carrier status
STDs
Zoonoses
Disease cycles

Question 15

Modes of transmission

Answer 15

• contact: direct body, indirect with fomite. Ex: cough, sneeze, talking
• vehicles: nonliving carrier of pathogen. Ex: air, food
• vectors: living carrier of pathogen (mechanical or biological)

Question 16

Herd immunity

Answer 16

Enough of a population are vaccinated prevent the few that aren’t from becoming sick

Question 17

Controlling acquired disease transmission

Answer 17

Isolation
Quarantine 
Immunization 
Vector control 
Sanitization and hygiene

Question 18

Public health organizations

Answer 18

CDC: us government. In charge of vaccination schedules, best practices
WHO: worldwide. Deal with epidemics and provide healthcare and education to 100 of the poorest countries
Notifiable diseases

Question 19

Nosocomial infections

Answer 19

Infections acquired while in a medical facility

Question 20

Exogenous

Answer 20

Source outside of you

- patient/ doctor

Question 21

Endogenous

Answer 21

Source from inside your own body

- c. Diff may be in microflora, but antibiotics allow it to grow faster

Question 22

Contributing factors to infection

Answer 22

Patient susceptibility
Microbial virulence
Disruption of microflora

Question 23

Controlling transmission

Answer 23

Universal precautions: gloves, face masks
Minimizing invasive procedures
Surveillance: monitoring for pathogens
Antibiotic use: don’t over prescribe

Question 24

Common source outbreak

Answer 24

Due to all coming in contact with a contaminated source

Question 25

Propagated epidemic

Answer 25

Passed from person to person (colds)