HLTH 4011 FINAL

Which specific persons were mentioned as being vulnerable to this specific outbreak of whooping cough?

• Latino farm workers

• Children/infants under the age of 3 months (latino background)

Which specific places were mentioned as being vulnerable to this specific outbreak of whooping cough?

Fresno County, California (central valley)

Which specific times of the year were mentioned as being vulnerable to whooping cough?

May, July, August (peak season in the summer)

What are the factors impacting the public health importance of the problem for surveillance?

• Volatility (or changes) of incidence/prevalence

• Severity of sequela (or consequences)

• Virulence/mortality

• Communicability

• Potential for outbreak

• Public concern

ability to ______, ______, or ______ the problem.

prevent, control, treat

Capacity of the health system to implement ______ ________ for the problem.

control measures

Disease outbreaks are more likely to be investigated when…

• number of affected persons is large

• health-related event is severe

• control measures exist

• outbreak has the potential to spread

What is the method for documenting or tracking events or persons over time?

Registries

What is the name of the permanent record of persons or events?

Registries

What do diseases registries usually include?

diagnostic, treatment, and outcome information

What are registries of vital events?

birth, marriage, death

what are registries used to track in preventative medicine?

immunizations

Disease-specific registries

blindness, birth defects, cancer, psychiatric cases

Registries of persons at-risk or exposed

atomic bomb survivors, World Trade Center survivors

what is reporting of certain diseases as specified by law, regulation, or agreement that is made to a state or local health agency?

Notification

Reporting/underreporting of notifiable diseases:

For rare, serious diseases of public health importance (e.g., rabies, plague, botulism) reporting approaches 100%

what are other non-life threatening diseases (e.g., shigellosis) can be as low as 9%

• Non-symptomatic

• Did not see a physician

• Not reported to the health department

What does it mean by the CDC MMWR?

CDC Morbidity and Mortality weekly report

The proportion of people with a health condition (i.e., cases) that are correctly identified by a screening or case definition

Sensitivity

What is the ability of surveillance to detect (and exclude) persons not having the health problem (i.e., non-cases) it is intended to detect?

Specificity

Which term in our text/slides refers to the proportion of persons without a health condition (non cases) that are correctly identified by a screening or case definition?

Specificity

What is a true positive, and what cell does it go in?

• A positive test for a person who has the condition

• Cell A

What is a false positive, and what cell does it go in?

• A positive test for a person who actually does not have the condition

• Cell B

What is a false negative, and what cell does it go in?

• A negative test for a person who actually has the condition

• Cell C

What is a true negative, and what cell does it go in?

• A negative test for a person who does not have the condition

• Cell D

What are the treatment implications of a false positive?

Doesn’t have asthma, unnecessary treatment

What are the treatment implications of a false negative?

Has asthma, not getting treated when they should

For a sensitivity rate calculation, what goes in the numerator? denominator?

• numerator - those with the condition who were correctly identified (true positives)

• denominator - all those with the condition, regardless of whether they were identified correctly

• All cases: True positives & False negatives

what is the formula for sensitivity rates?

A/(A+C)

• true positives divided by the sum of true positives and false negatives

what are sensitivity rate ranges?

• Can range between 0% and 100%

• The higher the rate, the more accurate the test is in detecting cases

• Higher sensitivity = fewer false negatives

For a specificity rate calculation, what goes in the numerator? denominator?

• Numerator: those without the condition who were correctly identified (True negatives)

• Denominator: all those without the condition, regardless of whether they were identified correctly

• All non-cases: True negatives & False positives

What is the formula for specificity rates?

D/(B+D)

• True negatives divided by the sum of true negatives and false positives

what are specificity rate ranges?

• Can range between 0% and 100%

• The higher the rate, the more accurate the test is in detecting non-cases

• Higher specificity = fewer false positives

What does it mean when either sensitivity or specificity is 80% or lower?

poor/unacceptable

• Low sensitivity = too many false negatives

• Low specificity = too many false positives

What is the primary way that clusters (suspected outbreaks) are detected?

• Reviewing ________ data.

Surveillance

what is the most important purpose/reason of field investigation?

control the outbreak and prevent additional cases

What are surveillance related changes that should be considered and controlled for in suspected outbreaks (clusters)?

changes in:

• reporting (notification)

• population (size, demographics)

• diagnosis (# tested, type of tests)

• case definition (AIDS in 1993)

analyzing by person:

Age, gender, race/ethnicity, school or workplace, presence of risk factors (e.g., cigarette smoking, recent travel)

analyzing by place:

Spot maps (small outbreaks) and area maps (larger outbreaks), demonstrate clusters and patterns

analyzing by time:

Display in a table by day, week, month, year, decade, etc.

The illustration of a measles outbreak is most consistent with which epi-curve type?

Propagated

What is the type of outbreak that might occur in a point source outbreak?

foodborne outbreaks

what is the example of a continuous common source?

John Snow Study

What disease outbreak is related to propagated (progressive source)?

measles

when calculating relative risk, what is the formula for attack rate exposed? unexposed?

• Ill exposed/Total exposed

• Ill unexposed/Total unexposed

(percent, so multiply by 100)

what is the formula for calculating risk ratio?

Exposed attack rate/Unexposed attack rate (not a percent)

RR = 1

• identical risk among groups (exposed and unexposed)

• Hypothesis about exposure (suspected risk factor) is incorrect

RR > 1

• increased risk for the exposed group (numerator)

• Hypothesis about exposure is correct

RR < 1

• increased risk for the unexposed group (denominator)

• Finding about exposure is the opposite of the hypothesis

Any food/drink item with a Risk Ratio greater than ____ warrants further investigation

2

when to implement control and prevention measures?

As soon as possible (ASAP)

what are control measures usually directed against?

one or more chain of transmission

what is the statistical analysis program used for the project?

SPSS

Categorical variable-types

• Nominal variable (no numerical ranking)

• Ordinal variable (numerically ranked, not necessarily evenly ranked)

• Interval variable (open-ended, assess numeric variables)

What types of questions are nominal?

• Yes/no variables are nominal variables

• For Yes/No questions, it is important to consider whether “not applicable” (N/A) should be an option

what types of questions are ordinal?

• Likert scale variables are ordinal variables

• Assessing behaviors (how often)

  • 1. Never

  • 2. Rarely

  • 3. Sometimes

  • 4. Often

  • 5. Always

what types of questions are interval?

Open-ended questions that assess quantitative (numeric) variables are continuous variables

is this an example of categorical or continuous? What is highest number of drinks you have consumed in a day?

Continuous

What do you do in SPSS when you are addressing missing data?

leave it blank

What survey revision strategies were utilized?

• part 1: added/changed 4 questions based off of existing surveys

• part 2: pilot test in class (feedback)

what are measures of central location?

• mean (average values)

• median (middle value)

• mode (most popular value(s))

what is epidemiological range?

from minimum value to maximum value (11-29)

what is statistical range?

subtract the minimum from the maximum (29-11 = 18)

what is standard deviation?

measure of spread or variability

what did column 1 have in the frequency table?

Response options

what does column 2 have in the frequency table?

frequency

what does column 3 have in the frequency table?

percentage

what are the factors that hindered control/prevention in the AIDS outbreak?

not closing the bathhouses, at the beginning they didn’t know what the disease was, lack of funding, gay stigma, blood banks pushing back (not wanting to test for the disease)

what person and place characteristics increased risk in the AIDS outbreak?

• gay males, Haitian refugees, people with hemophilia

• Miami, New York, Los Angeles, San Francisco

Sensitivity and/or specificity rates mentioned in the movie?

Hepatitis B, 88%

The primary purpose for conducting field investigations is to control the outbreak and prevent additional cases. In addition to this, list another purpose for conducting a field investigation that was mentioned in our slides.

address public concerns, opportunity to learn