infectious disease

Question 1

infectious disease

Answer 1

an illness due to a specific infectious agent or its toxic products that arises through transmission from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector, or inanimate environment

Question 2

features that make infectious diseases different from other diseases

Answer 2

1. a case may also be a risk factor due to contact
2. a case may be a source without being recognized: asymptomatic
3. urgency at a population level
4. preventive measure
5. cause is often known

Question 3

infectious disease epidemiology characteristics

Answer 3

1. deals with 2 or more populations
2. a case is a risk factor
3. case if often known
4. surveillance

Question 4

what is infectious disease epidemiology used for

Answer 4

1. identification of causes of new, emerging infections
2. surveillance of infectious diseases
3. identification of the source of outbreaks
4. studies of routes of transmission and natural history of infections
5. identification of new interventions

Question 5

epidemiologic triad

Answer 5

host
vector
agent
environment

Question 6

environment

Answer 6

could include geography, quality of ari and of life

Question 7

agent

Answer 7

determines the degree of infectivity, virulence, survival, antigenic stability, pathogenicity and immunogenicity

Question 8

modes of transmission

Answer 8

person to person
vector
common vehicle (water, food)
mechanical vectors (toothbrush, door handles)

Question 9

subclinical disease

Answer 9

disease that is not clinically apparent and is not destined to be clinically apparent

Question 10

clinical disease

Answer 10

characterized by signs and symptoms

Question 11

carrier

Answer 11

an individual who harbours the organism but is not infected: can infect others

Question 12

dynamic of infectiousness

Answer 12

infection; latent period; infectious period; non-infectious

Question 13

dynamics of disease

Answer 13

infection; incubation period; symptomatic period; non-diseased

Question 14

incubation period

Answer 14

the interval between the time of contact and/ or entry of agent and onset of illness: time required for the multiplication of microorganisms

Question 15

epidemiology of tuberculosis

Answer 15

exposure; subclinical infection; infectious tuberculosis and non-infectious tuberculosis; death

Question 16

diagnosis criteria for tuberculosis

Answer 16

1. tuberculin skin test (TST): low specificity
2. interferon-gamma release assay (IGRA): high specificity

Question 17

latent tuberculosis infection

Answer 17

people with LTBI have tuberculosis in their bodies, but do not have TB disease and cannot spread the infection to other people

Question 18

agent for HIV

Answer 18

free virus

Question 19

HIV infection stages

Answer 19

primary infection
clinically asymptomatic stage
symptomatic HIV infection
progression from HIV to AIDS

Question 20

latent period

Answer 20

time interval from infection to being infectious

Question 21

infectious period

Answer 21

time during which the host can infect another host

Question 22

symptomatic period

Answer 22

period in which symptoms of the disease are present

Question 23

endemic

Answer 23

habitual presence of a disease in a given geographic area

Question 24

epidemic

Answer 24

the occurrence of a group of illnesses of a similar nature within a given community or region over normal expectancy and derived from a common or a propagated source

Question 25

pandemic

Answer 25

a worldwide epidemic

Question 26

herd immunity

Answer 26

resistance of a group to an attack by a disease to which a large proportion of members of the group are immune

Question 27

virulence

Answer 27

severity of the disease produced by the organism

Question 28

how is virulence expressed as

Answer 28

number of cases of overt infection/ number of total cases

Question 29

attack rate

Answer 29

attack rate = number of people at risk who develop disease/ number of people at risk during a specified period of time

Question 30

individualistic R0

Answer 30

number of infections an infected person would generate throughout their infection if everyone they encountered were susceptible

Question 31

population R0

Answer 31

the average force for the growth of infection in a population where everyone is susceptible

Question 32

force of infection

Answer 32

the risk of being infected

Question 33

equation for R0

Answer 33

R0= p x c x d
p= transmission probability per exposure
c= number of contact per unit time
d= duration of infectious period