Disease Detectives Flashcards

Disease

A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.

Detective

a person whose occupation is to investigate and solve problems

Disease

A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.

Detective

a person whose occupation is to investigate and solve problems

Injury

an act or event that causes someone or something to no longer be fully healthy or in good condition

Health

a person's mental or physical condition

Disability

the condition of being unable to do things in the normal way

Food Borne Illness

Illness caused by food contaminated with bacteria, viruses, parasites, or toxins.

Calculator

something used for making mathematical calculations, in particular a small electronic device with a keyboard and a visual display.

Biological agent

a bacterium, virus, protozoan, parasite, or fungus that can be used purposefully as a weapon

Physical agent

source of energy that may cause injury or disease

Investigative Skills

skills that involve getting to the truth or gathering facts

Epidemiology

the branch of medicine that deals with the incidence, distribution, and possible control of diseases and other factors relating to health

Epidemiological Curve

a histogram showing the course of the disease or outbreak to identify the source of the exposure

Hypothesis

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation

Observation

an act or instance of viewing or noting a fact or occurrence for some scientific or other special purpose

Inference

a conclusion reached on the basis of evidence and reasoning

Prediction

a statement about what will happen or might happen in the future

Calculation

an assessment of the risks, possibilities, or effects of a situation or course of action or a mathematical determination of the size or number of something

Conclusion

a judgment or decision reached by reasoning

Observational Studies

study determinants of health problems

Bacteria

a large group of unicellular microorganisms that have cell walls but lack organelles and an organized nucleus, including some that can cause disease

Virus

an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a hos

Parasite

an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense

Protozoa

a large group of one-celled organisms (called protists) that live in water or as parasites

Natural toxins

chemicals that are naturally produced by living organisms. These are not harmful to the organisms themselves but they may be poisonous to other creatures, including humans, when eaten

Pathogenic agents

cowpox, ebola, hepatitis, influenza, and rabies

Pathogen

a bacterium, virus, or other microorganism that can cause disease

Prion

a protein particle that is believed to be the cause of brain diseases such as BSE, scrapie, and Creutzfeldt-Jakob disease

Scientific method

a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses

Chronic diseases

a disease that lasts 3 months or more, generally cannot be prevented by vaccines or cured by medication, and they don't just disappear

Environmental problems

issues with the planet's systems (air, water, soil, etc.) that have developed as a result of human interference or mistreatment of the planet

Behavioral problems

symptomatic expressions of emotional or interpersonal maladjustment especially in children

Infectious diseases

disorders caused by organisms — such as bacteria, viruses, fungi or parasites

Outbreak

more cases of a particular disease than expected in a given area or among a specialized group of people over a particular period of time, more localized

Epidemic

large numbers of people over a wide geographic area affected

Pandemic

an epidemic occurring over a very wide area (several countries or continents) and usually affecting a large proportion of the population

Cluster

an aggregation of cases over a particular period esp. cancer & birth defects closely grouped in time and space regardless of whether the number is more than the expected number

Public Health Surveillance

the systematic collection, analysis, interpretation, and dissemination of health data to gain knowledge of the pattern of disease occurrence in order to control and prevent disease in the community

Proper diagnosis

verify the procedures used to diagnose the problem and check methods used for identifying infectious and toxic chemical agents

Commonality

interview several persons who became ill to gain insight concerning possible cause, source, and spread of disease or problem

Case definition

establish with the 4 components or standard criteria for determining who has the disease or condition

Clinical information

about the disease or condition

Time sequence

specific time during which the outbreak or condition occurred

Identification of specific cases

kind & number - count specific cases

Confirmed

have diagnosis with case definition plus lab verification

Probable

many factors point to diagnosis but may lack lab verification

Possible

some factors point to diagnosis

Line Listing

chart of specific cases including information about each case

Cohort

based upon exposure status whether or not they have outcome (illness) works forward from exposure

Sample Cohort Study; Yes

One day, at a party with 400 people, some people ate salad and became sick. Is this scenario an example of a Food Borne Illness?

Attack rate

the rate that a group experienced an outcome or illness

How to calculate attack rate

For the exposed, use this formula: a ÷ (a+b).

For the unexposed, use this formula:

c ÷ (c + d) Both formulas use variables that are in the table for an example of cohort study. After doing the arithmetic, the results should be in percentage form.

Relative Risk

estimates the extent of the association between an exposure and a disease. It estimates the likelihood of developing the disease in the exposed group as compared to the unexposed group

How to calculate relative risk

[a ÷ (a+b)] / [c ÷ (c+d)]

Relative risk > 1

This indicates a positive association or an increased risk. This risk increases in strength as the magnitude of the relative risk increases.

Relative risk = 1

This indicates that the incidence rates of disease in the exposed group is equal to the incidence rates in unexposed group. Therefore the data does not provide evidence for an association.

Host

agent capable of causing disease & its source host or persons susceptible to agent + environment allowing them to get together

Retrospective

starts at exposure in past & moves forward to outcome

Prospective

starts a present exposure and moves forward in time to outcome

Control group

a selected group who has similar characteristics to the sick group but is not ill

Case-Control

works backward from effect or illness to suspected cause

Sample Case-Control Study

Several patients were diagnosed with Hepatitis A.

Odds Ratio

This is calculated to evaluate the possible agents & vehicles of transmission.

How to calculate odds ratio

Odds of exposure in cases/ Odds of exposure in controls = (a / c) / (b / d) = [a (d)] / [b (c)]

5.8

This means that people who ate at Restaurant A were _ times more likely to develop hepatitis A than were people who did not eat there.

Temporality

cause/exposure must precede effect/outcome

Consistency

observation of association must be repeatable in different populations at different times

Coherence

exposure is always associated with outcome/ outcome is always caused by the specific exposure; (1-1 relationship)

Strength of association

relationship is clear and risk estimate is high

Biological plausibility

biological explanation makes sense

Dose

increasing risk is associated with increasing exposure; aka response or biologic gradient

Oral briefing

inform local health officials or other need-to-know groups as soon as information is available

Written report

usually done in scientific format for future reference, legal issues, and education

Random Error

the divergence due to chance alone, of an observation on sample from the true population value, leading to lack of precision in measurement of association

Bias

systematic error in an epidemiologic study that results in an incorrect estimation of the association between exposure and health-related event

Non-Causal Relationships

Non-Causal Relationships

Confounding

This occurs when the effects of two risk factors are mixed in the occurrence of the health-related event under study. This also occurs when an extraneous factor is related to both disease and exposure.

Math terms

Mean, Median, Mode, Variance, Standard deviation, Standard error, Confidence intervals of means

Mean

the value obtained by dividing the sum of several quantities by their number; an average

Median

denoting the middle term of a series arranged in order of magnitude, or (if there is no middle term) the average of the middle two terms

Mode

the value that occurs most frequently in a given set of data

Variance

the average of the squared differences from the mean

Standard deviation

a measure of how spread out numbers are

Standard error

This is a measure of the statistical accuracy of an estimate, equal to the standard deviation of the theoretical distribution of a large population of such estimates. To find this, you divide the standard deviation by the square root of n, when n is the number of observations.

Confidence intervals of means

an interval estimate combined with a probability statement

Z-test

a statistical test used to determine whether two population means are different when the variances are known and the sample size is large

T-test

an analysis of two populations means through the use of statistical examination

Paired T-test

a statistical technique that is used to compare two population means in the case of two samples that are correlated

Chi-square

relating to or denoting a statistical method assessing the goodness of fit between observed values and those expected theoretically

McNemar test for paired data

a statistical test used on paired nominal data and is applied to 2 × 2 contingency tables with a dichotomous trait, with matched pairs of subjects, to determine whether the row and column marginal frequencies are equal

Fischers exact test

It used when you have two nominal variables. A data set like this is often called an "R×C table," where R is the number of rows and C is the number of columns.

Cochran Mantel-Haenszel summary odds ratio

a technique that generates an estimate of an association between an exposure and an outcome after adjusting for or taking into account confounding

High School: Stuff to do for regionals and state

1. Recognize differences between study designs ,Types of Error, and do Statistical Analysis

2. Calculate measures of risk (e.g. relative risk or odds ratio) when given a description of the study design

3. Calculate measures based on data that is not given but that can be readily extracted.

4. Recognize how gaps in information influence the ability to extend conclusions to the general population.

High School: Stuff to do for nationals

1. Recognize unmentioned factors that may influence results.

2. Recognize Types of Error and do Statistical Analysis

3. Convert between rates with different basic units (e.g. incidence per 10000 persons/year to incidence per 100 persons/week).

4. Propose a means to evaluate the effectiveness of an intervention or control program.

Chain transmission

It is a chain of six factors that can lead to successful transmission. 1. An agent (something that can infect another Ex fungi, virus, bacteria, protozoa). 2. A reservoir- a place where Bacteria can easily multiply and grow (ex: humans, food, animals, insects). 3. A portal of exit. This is a way that germs can easily leave the human body (ex Mouth, intestines, mouth). 4. Transmission. This is when the disease is spread. It can be spread by contact with an infected source. 5. Portal of entry. How the disease enters the body. 6. Susceptible host. A host that can be infected.

Risk

The probability that an individual will be affected by, or die from, an illness or injury within a stated time or age span.

Vector

An animate intermediary in the indirect transmission of an agent that carries the agent from a reservoir to a susceptible host. An organism that transmits the infection as a mosquito transmits the malaria protozoans.

Fomite

A physical object that serves to transmit an infectious agent from person to person. A comb infested with one or more head lice would be a ________ or the dust particles containing infectious cold virus that remain after droplets of infected saliva are coughed into the air.

Zoonosis

An infectious disease that is transmissible from animals to humans.

Surveillance

The systematic, ongoing collection, analysis, interpretation, and dissemination of health data. The purpose of public health surveillance is to gain knowledge of the patterns of disease, injury, and other health problems in a community so that we can work toward controlling and preventing them.