Scioly Disease Detectives 2025

Epidemiology

The study of what causes disease, how disease is distributed, and how we can control the spread of disease.

Classical epidemiology

Population oriented and studies the community origins of health problems related to nutrition, environment, and human behavior.

Clinical epidemiology

Studies patients in health care settings in order to improve diagnosis, treatment, and prognosis.

Infectious Disease Epidemiology

Heavily dependent on laboratory support.

Chronic Disease Epidemiology

Dependent on complex sampling and statistical methods.

Descriptive epidemiology

Considers time/place/person data on a disease to determine trends. Answers questions like who/what/where/when.

Analytic epidemiology

Involves hypothesis testing to determine the cause of disease (causal relations). Answers questions like why/how.

Disease

Infection that results in signs (objective) and symptoms (subjective).

Opportunistic disease

A disease that causes sickness when given the opportunity of a damaged or weakened immune system.

Noscomial disease

An infection that is acquired in a hospital.

Iatrogenic disease

An illness that is caused by medication or a physician.

Chronic infection

An infection where the agent is continuously present and detectable.

Latent infection

An infection where the agent is continuously present, but can remain dormant before reactivation.

Incubation period

Time in between when a person comes into contact with an agent of disease and when they first show symptoms or signs of disease.

Latent period

Time in between when a person comes into contact with a pathogen and when they become infected.

Asymptomatic

Displays no signs or symptoms, but is infected and can carry the disease.

Susceptibility

To what extent a member of a population is able to resist infection.

Susceptible individual

A member of a population at risk of becoming infected by a disease.

Pathogenicity

The property of causing disease following infection.

Virulence

The property of causing severe disease.

Infectivity

The property of establishing infection following exposure.

Morbidity

The rate of disease in a population.

Mortality

The rate of death in a population.

Case fatality rate

The rate of death due to a disease in the diseased population.

Prevalence

The number of existing cases of disease in a given population.

Point prevalence

The number of existing cases of disease in a given population at a given point in time.

Period prevalence

The total number of cases of disease in a given population over a period of time.

Incidence

The rate of new cases of disease in a given population over a period of time.

Attack rate

The number of people infected, divided by the total sample. There should be a high attack rate in those exposed and a low attack rate in those unexposed.

Person-time

The sum of the time during which each individual in a population was at risk for a disease.

Index case

Also known as 'patient zero'; the first case of a disease in a specific setting.

Etiology

The cause of a disease.

Pathology

The science of the study and diagnosis of disease and injury.

Determinant

Any factor that brings about change in a health condition.

Herd immunity

A critical proportion of a population is immune to a disease such that the entire population is protected.

Fulminant

A sudden and severe onset.

Quarantine

When you may have been exposed.

Isolation

When you have been exposed.

Prepare for field work

Research the disease or situation and gather needed supplies and equipment to conduct the investigation.

Establish the existence of an outbreak

Consider severity, potential for spread, public concern, and availability of resources.

Verify the diagnosis

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

Interview several persons who became ill

Gain insight concerning possible cause, source, and spread of disease or problem.

Screen ill persons

Collect clinical and environmental samples and get them tested in order to determine agent.

Construct a working case definition

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

Clinical information about the disease

One of the four components for determining who has the disease or condition.

Characteristics of the affected people

One of the four components for determining who has the disease or condition.

Location or place

One of the four components for determining who has the disease or condition.

Time sequence

One of the four components for determining who has the disease or condition.

Confirmed cases

Lab confirmation combined with signs and symptoms.

Probable cases

Signs and symptoms but no lab confirmation.

Possible cases

Some signs and symptoms, but unclear.

Line listing

A chart of cases which includes identifying information, clinical information, time, person, place, and risk factors.

Find cases systematically

Collect identifying information, demographic information, clinical information, risk factor information, and reporter information for each case.

Perform descriptive epidemiology

Consider the time, place, and person of an outbreak, involving epi curves, spot maps, and case information.

Develop hypotheses

Use the agent/host/environment triad to create a hypothesis.

Evaluate hypotheses epidemiologically

Perform studies (case-control or cohort) to validate a hypothesis.

Reconsider, refine, and re-evaluate hypotheses

Use experimental data to narrow the hypothesis.

Compare and reconcile with laboratory studies

Laboratory evidence is necessary to confirm a hypothesis.

Implement control and prevention measures

Should be performed as soon as possible when the source is known to disrupt the chain of transmission.

Initiate or maintain surveillance

Evaluate the success of control and prevention measures.

Communicate findings

Can include an oral briefing, written report, PSA, etc.

PulseNet

A network of labs across the US that helps epidemiologists identify new foodborne, waterborne, and zoonotic disease outbreaks.

Key premises of PulseNet

Early detection/reporting, and hyper-specific DNA fingerprinting.

Steps of PulseNet surveillance

Sequence of steps that facilitate rapid implementation of specific control and prevention measures.

Clinical laboratory processes

Isolate the bacteria that is making the patient ill, for example, Salmonella.

Salmonella

A type of bacteria that can cause illness.

Pulsed-field gel electrophoresis (PFGE)

A traditional process used to produce a DNA fingerprint of bacteria.

Whole-genome sequencing (WGS)

A modern technique that provides a unique DNA pattern for bacteria, offering higher precision than PFGE.

DNA fingerprint

A unique pattern produced by analyzing the DNA of an organism.

Clusters

Groups of matching DNA patterns that prompt investigations into outbreaks.

Microbiologists

Scientists who study microorganisms, including bacteria.

Epidemiologists

Public health professionals who investigate the causes and spread of diseases.

Next Generation Sequencing (NGS)

Techniques used in WGS to generate a complete DNA fingerprint.

Sanger sequencing

A traditional method of DNA sequencing that is more accurate than NGS.

Surveillance

The systematic collection and analysis of health data to monitor disease patterns.

Data Collection

The first step in surveillance, involving gathering reports, records, and surveys.

Data Analysis

The second step in surveillance, involving the examination of data to identify illness locations.

Data Interpretation

The third step in surveillance, which identifies the person, place, and time of health events.

Data Dissemination (Distribution)

The fourth step in surveillance, involving sharing information with the public and stakeholders.

Link to Action

The fifth step in surveillance, emphasizing the need for action based on collected data.

Passive Surveillance

A type of surveillance where diseases are reported by healthcare providers.

Active Surveillance

A type of surveillance where health agencies actively seek reports from healthcare providers.

CDC

Centers for Disease Control and Prevention, a national public health agency.

Electronic database

A digital system for storing and managing health data.

Illness interviews

Conversations conducted by epidemiologists to gather information from patients.

Health problems

Conditions that affect the physical or mental well-being of individuals.

Public health decisions

Choices made to protect and improve the health of communities.

Control measures

Actions taken to prevent or reduce the spread of diseases.

Health event

An occurrence that impacts the health of individuals or populations.

Active surveillance

A method used during an outbreak or specific epidemiological investigation.

Syndromic surveillance

Monitoring signs of the disease (such as school absences or prescription drug sales) as a proxy for the disease itself, requiring symptoms to be infrequent, severe, and unique.

Sentinel surveillance

Involves professionals selected to represent a specific geographic area or group to report health events to health agencies, used when high-quality data can't be obtained through passive surveillance.

Hill's Criteria for Causation

Nine criteria that must be met to establish a cause-and-effect relationship.

Strength of Association

A criterion where the relationship is clear and the risk estimate is high.

Consistency

A criterion where the observation of association must be repeatable in different populations at different times.

Specificity

A criterion where a single cause produces a specific effect.

Alternative Explanations

A criterion that involves consideration of multiple hypotheses before concluding whether an association is causal.

Temporality

A criterion stating that the cause/exposure must precede the effect/outcome.

Dose-Response Relationship

A criterion where an increasing amount of exposure increases the risk.

Biological Plausibility

A criterion where the association agrees with currently accepted understanding of biological and pathological processes.