OUTBREAK INVESTIGATION

Question 1

8 examples of LEVELS OF DISEASE

Answer 1

1. BASELINE
2. SPORADIC
3. ENDEMIC
4. HYPERENDEMIC
5. EPIDEMIC
6. OUTBREAK
7. CLUSTER
8. PANDEMIC

Question 2

[LEVELS OF DISEASE]

• The amount of a disease that is usually present in a community;
• the observed but not
  necessarily the desired level;
• regarded as the
  expected level of disease

Answer 2

BASELINE

Question 3

[LEVELS OF DISEASE]

• A disease that occurs infrequently and
  irregularly

Answer 3

SPORADIC

Question 4

[LEVELS OF DISEASE]

• The constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area

Answer 4

ENDEMIC

Question 5

[LEVELS OF DISEASE]

• The persistently high levels of disease
  occurrence

Answer 5

HYPERENDEMIC

Question 6

[LEVELS OF DISEASE]

• An increase, often sudden, in the number of
  cases of a disease above what is normally
  expected in that population in that area

Answer 6

EPIDEMIC

Question 7

[LEVELS OF DISEASE]

• Similar to an epidemic but is often used for a
  more limited geographic area

Answer 7

OUTBREAK

Question 8

[LEVELS OF DISEASE]

• An aggregation of cases grouped in place and
  time that are suspected to be greater than the
  number expected, even though the expected
  number maybe unknown

Answer 8

CLUSTER

Question 9

[LEVELS OF DISEASE]

• An epidemic that has spread over several
  countries or continents, usually affecting a large number of people

Answer 9

PANDEMIC

Question 10

three TYPES OF OUTBREAK

Answer 10

1. COMMON SOURCE
2. PROPAGATED EPIDEMIC
3. MIXED EPIDEMIC

Question 11

[TYPES OF OUTBREAK]

• People are exposed continuously or intermittently to a harmful source
• Period of exposure maybe brief or long
• Intermittent exposure often results in an epi curve with irregular peaks that reflect the timing and the extent of exposure

Answer 11

COMMON SOURCE

Question 12

[TYPES OF OUTBREAK]

‘COMMON SOURCE’ examples

Answer 12

A. COMMON POINT SOURCE
B. CONTINUOUS EXPOSURE
C. INTERMITTENT

Question 13

[TYPES OF OUTBREAK]

‘COMMON SOURCE’

• Cases were all exposed to the same source during a brief period of calendar time;
• Typically shows a sharp upward slope and a gradual downward slope
• Is a common source outbreak in which the period of exposure is brief, and all cases occur within one incubation period

Answer 13

COMMON POINT SOURCE

Question 14

[TYPES OF OUTBREAK]

‘COMMON SOURCE’

• Continuous exposure will often cause cases to rise gradually (and possibly to plateau, rather than to peak)

Answer 14

CONTINUOUS EXPOSURE

Question 15

[TYPES OF OUTBREAK]

‘COMMON SOURCE’

• Brief, sporadic exposure period
• Irregular peaks- reflect timing and extent of exposure
• The gaps between the outbreaks might initially suggest person-to-person transmission followed by an incubation period.

Answer 15

INTERMITTENT

Question 16

[TYPES OF OUTBREAK]

• Spread is from person-to-person
• Can last longer than source outbreaks
• Disease agent may replicate in a susceptible host as part of the transmission cycle;
• May have multiple waves
• The classic epi curve for a propagated
  outbreak has progressively taller peaks, one incubation period apart

Answer 16

PROPAGATED EPIDEMIC

Question 17

[TYPES OF OUTBREAK]

• Involve both a single, common exposure to an infectious agent and secondary propagative spread to other individuals (e.g., person to person transmission)
• Either same disease introduced separately or different diseases with different incubation periods introduced around the same time

[Examples:]
Many food borne pathogens (Salmonella, typhoid, Hepatitis A) and airborne organism (M. tuberculosis)

Answer 17

MIXED EPIDEMIC

Question 18

[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]

‘determine the TIME FRAME’

• Acute food poisoning: Staphylococci toxins, C. perfringens
• Heavy metal exposure: cadmium, copper, zinc
• Other poisonings: MSG, mushroom, shellfish poisoning

Answer 18

HOURS

Question 19

[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]

‘determine the TIME FRAME’

• Some food poisonings: Salmonella (1-2 ____), V. cholerae, C. jejuni
• Bacterial infections: Legionnaire’s disease, Mycoplasma pneumoniae
• Viral infections: influenza (1-3 _____), adenovirus (1-5 ____), enteroviral infections (5-6 _____)

Answer 19

DAYS

Question 20

[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]

‘determine the TIME FRAME’

• Common childhood disease: measles, mumps, rubella (2-3 _____)
• Hepatitis A (2-6 ______)

Answer 20

WEEKS

Question 21

[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]

‘determine the TIME FRAME’

• Hepatitis B (2-6 weeks)
• Rabies (0.5-12 _____)

Answer 21

MONTHS

Question 22

[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]

‘determine the TIME FRAME’

• Radiation induced leukemia
• Kuru (1-27 ______)

Answer 22

YEARS

Question 23

[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]

The _______ of susceptible persons who are
_________ to a source of infectious and become
_________.

Answer 23

number, exposed, infected

Question 24

[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]

The period of time over which __________ __________ are exposed to the ________.

Answer 24

susceptible persons, source

Question 25

[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]

The ___________ and ___________ incubation periods for the disease.

Answer 25

minimum, maximum

Question 26

• Type of incidence rate used when the occurrence of disease among a population at risk increases greatly over a short period of time, often related to specific exposure.
• Frequently used to describe the occurrence of
  foodborne illness, infectious disease, and other acute epidemics

Answer 26

ATTACK RATE

Question 27

formula for an attack rate

Answer 27

attack rate = 𝑖𝑙𝑙 / 𝑖𝑙𝑙+𝑤𝑒𝑙𝑙 𝑥100