chapter 16

Question 1

epidemiology

Answer 1

the study of factors and mechanisms that are involved in the frequency and spread of diseases which affect humans animals and plants

Question 2

etiologic agent

Answer 2

the cause of the disease

Question 3

morbidity rate

Answer 3

indicates the number of cases as a percentage of the population

Question 4

mortality rate

Answer 4

measure of deaths in the population

Question 5

prevalence rate

Answer 5

number of people infected at any one time

Question 6

incidence rate

Answer 6

new cases per unit population per unit time period

Question 7

all expressed in

Answer 7

in numbers per 100,000 people per year or as a percent of the population

Question 8

sporadic diseases

Answer 8

only seen occasionally

Question 9

endemic diseases

Answer 9

constantly present

Question 10

epidemic diseases

Answer 10

larger than expected number of cases in a short period of time

Question 11

pandemic diseases

Answer 11

worldwide epidemic

Question 12

propagated epidemics

Answer 12

person to person spread

Question 13

common source

Answer 13

single source for all individuals infected

Question 14

point source

Answer 14

common source operates for a short period of time

Question 15

continuous common source spread

Answer 15

the infection occurs for an extended period of time

Question 16

intermittent common source spread

Answer 16

infections occur for a period, stop and then begin again

Question 17

propagated spread

Answer 17

direct or indirect person to person contact
there is no single source of infection
each individual becomes a source for one or more subsequent individuals

Question 18

observational studies

Answer 18

data are gathered from study participants through measurements

Question 19

experimental studies

Answer 19

Use laboratory or clinical studies in which the investigator manipulates the study subjects to study connections between diseases and potential causative agents

Question 20

modes of disease transmission

Answer 20

contact
vehicle
vector

Question 21

what is a passive carrier

Answer 21

A person who carries and spreads a pathogen without being infected themselves

Question 22

what is an active carrier

Answer 22

A person who is infected and shows symptoms while spreading the disease.

Question 23

what is an asymptomatic carrier

Answer 23

A person who is infected but does not show symptoms, yet can still spread the disease.

Question 24

contact transmission

Answer 24

direct contact
indirect contact
droplets

Question 25

vehicle transmission

Answer 25

transmission is via a medium such as air food liquid these are all things routinely taken into the body they thus serve as vehicles into the body

Question 26

vector transmission

Answer 26

transmission of a pathogen by a living organism that carries and spreads the disease between hosts

Question 27

examples of diseases spread by biological vectors

Answer 27

Malaria – spread by mosquitoes Lyme disease – spread by ticks Plague – spread by fleas

Question 28

examples of diseases spread by mechanical vectors

Answer 28

on insect bodies salmonella E. coli

Question 29

R0

Answer 29

how contagious is an infectious disease

Question 30

R0 depends on 3 factors

Answer 30

duration of infectiousness The probability of infection being transmitted during contact: between a susecptible and infected individuals average rate of contact: between susceptible and infected individuals

Question 31

quarantine

Answer 31

applied to healthy people exposed to a disease during the the incubation period

Question 32

isolation

Answer 32

applies to person already infected limits the movement of such people and not necessarily to precautions during treatment

Question 33

notifiable disease

Answer 33

Infectious diseases that are potentially harmful to public health and must be reported by the physicians

Question 34

emerging infectious diseases

Answer 34

new to the human population or has shown an increase in prevalence in the previous twenty years

Question 35

emerging viruses

Answer 35

viruses that were previously endemic and have been expanded their hoist range to other species

Question 36

reemerging infectious diseases

Answer 36

a disease that is increasing in frequency after a previous period of decline examples: drug-resistant forms of tuberculosis, bacterial pneumonia and malaria

Question 37

herd immunity

Answer 37

Herd immunity is when enough people in a population are immune to a disease (through vaccination or previous infection), so the disease can't spread easily, even to those who aren't immune

Question 38

Common modes of transmission for nosocomial infections

Answer 38

elevator shaft bacteria from other patients ventilation ducts bacteria from outside bacteria from infected patient contamination from equipment bacteria from visitors or hospital personnel bacteria carried by insects

Question 39

disease eradication is difficult

Answer 39

1. available medical expertise is not always applied 2. Infectious agents adapt 3. Unknown or rare diseases become more significant 4. immigration, international travel, commerce

Question 40

how to investigate an outbreak in 7 steps

Answer 40

1. case investigation 2. cause investigation 3. control measures 4. conduct analytic study 5. conclusions 6. continue surveillanve 7. communicate findings