Science Olympiad Disease Detectives

Cluster

An aggregation of cases over a particular period closely grouped in time and space, regardless of whether the number is more than the expected number

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.

Epidemic

Large numbers of people over a wide geographical area are affected

Pandemic

An epidemic occurring over several countries or continents and affecting a large proportion of the population.

Surveillance

The systematic and 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 towards their prevention and control.

Plague

A serious, potentially life-threatening infectious disease that is usually transmitted to humans by the bites of rodent fleas. It was one of the scourges of our early history. There are three major forms of the disease: bubonic, septicemic, and pneumonic.

Vector

An animal that transmits disease. For example a mosquito is a vector for malaria.

Fomite

A physical object that serves to transmit an infectious agent from person to person.

Risk

The probability that an individual will be affected by, or die from, an illness or injury within a stated time or age span. Risk of illness is generally considered to be the same as the Incidence (see below) and the terms are used interchangeably. Age-span is not usually a consideration in this usage. Risk of death from a particular illness is expressed as the Case Fatality Rate (Number deaths due to a disease/Number with the disease) or the Cause-specific Mortality Rate (Number deaths due to a disease/Number in population). Age span is a more common consideration in this last usage.

Zoonosis

An infectious disease that is transmissible from animals to humans.

Incubation Period

Time in between when a person somes into contact with a pathogen and when they first show symptoms or signs of disease.

Endemic Disease

Present at a continuous level throughout a population/geographic area; constant presence of an agent/health condition within a given geographic area/population; refers to the usual prevalence of an agent/condition.

Classical Epidemiology

Population oriented, studies community origins of health problems related to nutrition, environment, human behavior, and the psychological, social, and spiritual state of a population. The event is more aimed towards this type of epidemiology.

Clinical Epidemiology

Studies patients in health care settings in order to improve the diagnosis and treatment of various diseases and the prognosis for patients already affected by a disease. These can be further divided into:

Infectious Disease Epidemiology

Heavily dependent on laboratory support

Chronic Disease Epidemiology

Dependent on complex sampling and statistical methods

Incidence

Is the number of new instances of disease in a population over a given time period

Prevalence

Is number of affected persons in the population at any given point in time

Duration

Time of the illness or condition

Environmental Causes of Health Problems

Smoking, air pollution

Flooding and drought

Extreme heat, UV exposure

Pesticides, chemical spills, lead contamination

Water pollutants, heavy metals

Ventilation pollutants

Noise induced hearing loss

Waste and toxic substance

Food contamination

Other pathogenic agents as prions

Foods most associated with food borne illness

Raw meat and poultry

Raw eggs

Unpasteurized milk

Raw shellfish

Raw fruits and vegetables

Unpasteurized fruit juice

Food processing concerns

Foods that mingle the products of several individual animals

A pathogen in one animal can contaminate may contaminate a whole batch of food mingling the products of several animals as bulk raw milk, pooled raw eggs or ground beef

A single hamburger may contain meat from hundreds of animals

A glass of raw milk may contain milk from hundreds of cows.

A broiler chicken carcass can be exposed to the drippings and juices of many thousands of other birds that went through the same cold water tank after slaughter.

Washing fruits and vegetables can decrease but not eliminate contamination

Processing food under less than sanitary conditions can cause outbreaks

Raw sprouts that are eaten without cooking may contain growing microbes

Storage and transport methods for food

Reducing the risk of food borne illness

Cook meat, poultry, and eggs thoroughly

Separate - don't cross-contaminate one food with another

Chill - refrigerate leftovers promptly

Clean - wash produce

Report - suspected food borne illnesses to the local health department

Strength of Association

Relationship is clear and risk estimate is high

Consistency

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

Specificity

A single cause produces a specific effect

Alternative Explanations

Consideration of multiple hypotheses before making conclusions about whether an association is causal or not

Temporality

Cause/exposure must precede the effect/outcome

Dose-Response Relationship

An increasing amount of exposure increases the risk

Biological Plausibility

The association agrees with currently accepted understanding of biological and pathological processes

Experimental Evidence

The condition can be altered, either prevented or accelerated, by an appropriate experimental process

Coherence

The association should be compatible with existing theory and knowledge, including knowledge of past cases and epidemiological studies