Ch 15 Epidemiology and Nosocomial Infections

Question 1

epidemiology

Answer 1

the study of factors and mechanisms involved in the frequency and spread of diseases and other health related problems within populations of humans, other animals, or plants.

Question 2

etiology

Answer 2

the cause of an infectious disease

Question 3

morbidity

Answer 3

the relative incidence of disease. Morbidity rate refers to the number of individuals affected by a disease

Question 4

mortality

Answer 4

the state of being subject to death. Mortality rate refers to the number of deaths in a population due to a disease

Question 5

endemic

Answer 5

the state of an infectious disease if it is present continually in a population of a particular area but both the number of reported cases and the severity of the disease remain too low to constitute a public health problem. (mumps)

Question 6

epidemic

Answer 6

arises when a disease suddenly has a higher than normal incidence in a population.

Question 7

Incidence

Answer 7

the number of new cases contracted within a set population during a specific tie period

Question 8

Prevalence

Answer 8

the total number of people infected within the population at any time

Question 9

Reservoirs of infection

Answer 9

sites in which organisms can persist and maintain their ability to infect. Can be either in humans, animals, or non living settings such as water.

Question 10

Zoonois

Answer 10

diseases that can be transmitted under natural conditions to humans from other vertebrate animals

Question 11

Portals of entry to the human body

Answer 11

skin and mucous membranes of the digestive, respiratory, and urogenital systems.

Question 12

Portals of exit to the human body

Answer 12

Nose, mouth (saliva), urethra (urine), mammary glands (milk), anus (feces), broken skin (blood)

Question 13

Disease Transmission

Answer 13

can be broken down into 3 different categories: contact transmission, vehicle transmission, and vector transmission

Question 14

Contact Transmission

Answer 14

transmission of a disease through contact with an infected individual. Can be direct (body contact between individuals), indirect (contact with nonliving organisms that can harbor and transmit an infectious agent from a living organism), and droplet ( when a person coughs, sneezes, or speaks near others)

Question 15

Vehicle Transmission

Answer 15

transmission of disease by vehicles (a non living carrier of an infectious agent that carries it from its reservoir to a host). Common vehicles include water, air, and food. Can also be blood and other body fluids

Question 16

Vector Transmission

Answer 16

transmission of a disease by vectors (living organisms that transmit disease). Can be mechanical (disease is carried on the the outside of the vector’s body) or biological (the infectious agent must complete part of it’s life cycle in the vector before it is transmitted.)

Question 17

Fomite (indirect contact transmission)

Answer 17

nonliving objects that can harbor and transmit an infectious agent

Question 18

aerosol (vehicle transmission)

Answer 18

a cloud of tiny water droplets or fine solid particles suspended in air

Question 19

Herd Immunity

Answer 19

the proportion of individuals in a community or population who are immune to a particular disease

Question 20

How does high herd immunity protect the entire population from an infectious agent, even susceptible individuals?

Answer 20

the disease can only spread among a small number of susceptible individuals in the population, and the likeluhood of transmitting the disease to others is small

Question 21

Methods of controlling disease

Answer 21

isolation, quarantine, immunization, and vector control

Question 22

Isolation

Answer 22

when a patient with a communicable disease is prevented from having contact with the general population

Question 23

quarantine

Answer 23

the separation of healthy human or animal carriers from the general population when they have been exposed to a communicable disease

Question 24

Immunization

Answer 24

an extremely effective means of controlling communicable diseases for which safe vaccines are available

Question 25

Vector Control

Answer 25

an effective means of controlling infectious
diseases if the vector, such as an insect or rodent,
can be identified and its habitat, breeding habits, and
feeding behavior determined.

Question 26

Public Health Organizations

Answer 26

Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO)

Question 27

Nosocomial Infection

Answer 27

an infection acquired in a hospital or other medical facility. Can be exogenous or endogenous .

Question 28

Exogenous Nosocomial Infection

Answer 28

cause by organisms that enter the patient from the environment

Question 29

Endogenous Nosocomial Infection

Answer 29

caused by opportunists among the patient’s own normal microflora

Question 30

Universal Precautions (6)

Answer 30

(1) always wear gloves and a gown
(2) wear protective eye and masks when dealing with blood and body fluid
(3) always wash hands before and after dealing with patients
(4) use disposable mouthpiece/airway for mouth to mouth
(5) discard needles and other sharp objects immediately into nearby special container
(6) clean spills of blood or fluids with gloves, wash with soap and water, and disinfect with bleach and water.

Question 31

Half of all nosocomial infections are caused by

Answer 31

E coli, Pseudomonas, S. aureus, and the Enterococcus species.

Question 32

Most common sites of nosocomial infection

Answer 32

urinary tract, surgical wounds, and respiratory tract