SURVEILLANCE AND EPIDEMIC OUTBREAK INVESTIGATION

Question 1

Common-vehicle exposure

Answer 1

From a source common to all

Question 2

Single exposure

Answer 2

Exposed only once

Question 3

Multiple exposures

Answer 3

Exposed several times

Question 4

Periodic contamination

Answer 4

Intermittent contamination

Question 5

Continuous contamination

Answer 5

Persistent contamination

Question 6

Clinical disease

Answer 6

Characterized by signs and symptoms

Question 7

Non-clinical disease:

Answer 7

Preclinical, Subclinical, Persistent (Chronic), Latent

Question 8

Preclinical

Answer 8

symptoms not yet apparent but the disease is biologically present and destined to progress to clinical

Question 9

Subclinical

Answer 9

symptoms not yet apparent but seropositive

Question 10

Persistent (Chronic)

Answer 10

manifestation of symptoms for years

Question 11

Latent

Answer 11

no active multiplication of the agent

Question 12

Carrier

Answer 12

Harbors organism, can be asymptomatic and seronegative

Question 13

Incubation period

Answer 13

Interval from receipt of infection to the time of onset of clinical illness

Question 14

Factors that affect incubation period

Answer 14

1. Time of replication
2. Site of replication
3. Dose of infectious agent

Question 15

Quarantine (quarante giorni)

Answer 15

Detention period of animal or human

Question 16

Critical variables in disease investigation:

Answer 16

1. When did the exposure take place?
2. When did the disease begin?
3. What was the incubation period for the disease?

Question 17

A person who acquires the disease from exposure e.g from contaminated food

Answer 17

Primary Case

Question 18

Secondary case

Answer 18

• A person who acquires the disease through exposure to primary case

Question 19

What are the questions to be asked for diseases that occur at more than an endemic level?

Answer 19

• WHO was attacked by the disease?
• WHEN did the disease occur?
• WHERE did the cases arise?

Question 20

Factors such as sex, age, race, and other host characteristics

Answer 20

WHO?

Question 21

question to be asked for certain diseases that occur with a certain periodicity

Answer 21

WHEN?

Question 22

WHERE

Answer 22

question for diseases that are NOT randomly distributed in time or place

Question 23

The occurrence of disease at an unusual or unexpected, elevated

Answer 23

Epidemics (disease outbreaks)

Question 24

Entire process of collecting, analyzing, interpreting, and reporting data on the incidence of death, diseases, and injuries and the prevalence of certain conditions, for promoting and safeguarding public health

Answer 24

Surveillance

Question 25

United States Federal agency responsible for surveillance HQ: Atlanta, Georgia

Answer 25

Centers for Disease Control and Prevention (CDC)

Question 26

Development of surveillance system requires (9):

Answer 26

• Clear objectives • Standardized reporting procedures • Case definition based on clinical findings • Determination of intensity of surveillance (Active vs. passive) • Determination of duration of surveillance (ongoing vs. time-limited) • Types of analysis (e.g.incidence, prevalence, case fatality ratio, etc.) • Plans for information dissemination (internet, publication, broadcast) • Pilot test performed and evaluated first before full system attempt • Continuous evaluation when full system is operational

Question 27

METHODS AND FUNCTIONS OF DISEASE SURVEILLANCE

Answer 27

Passive: Physicians (On going) Active: Surveillance body (As needed)

Question 28

ESTABLISHMENT OF BASELINE DATA

Answer 28

Through regular reporting and surveillance system

Question 29

Continued surveillance

Answer 29

Detect deviations from the usual pattern of data and prompts epidemiologists to explore

Question 30

Secular (Long-term) Trends

Answer 30

• Change in reporting = UNDERESTIMATE incidence • Change in surveillance = OVERESTIMATE prevalence

Question 31

Seasonal Variation

Answer 31

• Exhibited by many infectious diseases • Period of highest incidence depends on route of spread • Should be incorporated into calculations by epidemiologists

Question 32

Calendar year

Answer 32

• From Jan.01 to Dec.31

Question 33

Epidemiologic year

Answer 33

From month of lowest incidence in 1 year to the same month in the next year

Question 34

Epidemic threshold (WHO)

Answer 34

• Critical number or density of susceptible hosts required for an epidemic to occur • Used to confirm the emergence of an epidemic so as to set-up appropriate control measures

Question 35

Syndromic Surveillance

Answer 35

• Technique to rapidly detect epidemics and possible bioterrorism • Goal: characterize “syndromes consistent with bioterrorism agents •To prime the system-to report any such syndromes quickly •Provides early warning of a bioterrorism problem

Question 36

Purpose of evaluation

Answer 36

• To track progress of major interventions • To determine if intended changes were achieved • To gauge the impact of new vaccines,health policies,etc.

Question 37

Failure of a vaccine:

Answer 37

• A lack of change in disease rates • An increase in disease rates after an initial decrease • An increase in disease rates in a recently vaccinated group

Question 38

Importance of post marketing surveillance

Answer 38

• Investigators are able to detect any failure in the system • Measles immunization (2006 recommendations) • First dose:12-15 months old • Second dose: 4-6 years old • Third dose: about the age of 18

Question 39

Current and past data on the patterns of disease can

Answer 39

help governmental and voluntary agencies establish priorities for disease control efforts

Question 40

Epidemics (etymology: Greek “upon the population”)

Answer 40

• Can sometimes refer to just one case of a disease

Question 41

Endemic (etymology: Greek “within the population”)

Answer 41

• Disease occurs regularly at a more or less constant level

Question 42

Epizootic (etymology:Greek “upon the animals”)

Answer 42

• A disease outbreak in animal population

Question 43

Enzootic (etymology: Greek “within the animals”)

Answer 43

Disease deeply entrenched in an animal population but not changing much

Question 44

Attack rate

Answer 44

Proportion of exposed persons that become ill

Question 45

PROCEDURES / STEPS FOR INVESTIGATING AN EPIDEMIC

Answer 45

STEP 1. ESTABLISH DIAGNOSIS STEP 2. ESTABLISH EPIDEMIOLOGIC CASE DEFINITION STEP 3. IS AN EPIDEMIC OCCURRING? STEP 4. CHARACTERIZE EPIDEMIC BY TIME, PLACE, AND PERSON STEP 5. DEVELOP HYPOTHESIS REGARDING SOURCE, PATTERNS OF SPREAD, AND MODE OF TRANSMISSION STEP 6.TEST HYPOTHESIS STEP 7. INITIATE CONTROL MEASURES STEP 8. INITIATE SPECIFIC FOLLOW-UP SURVEILLANCE TO EVALUATE CONTROL MEASURES