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Glossary of Terms

Bacterium (plural: bacteria):
A microscopic one-celled organism. Some bacteria are essential for our survival and others may cause disease.

Diabetes:
The short name for the disease called diabetes mellitus. Diabetes results when the body is unable to maintain healthy levels of blood sugar because insulin levels are too low or the body is not able to use insulin. Insulin is responsible for converting blood sugar into energy. 

Epidemic:
An outbreak of disease that spreads within a specific region and/or country

Immune:
A state of being protected against infectious diseases by either specific or non-specific mechanisms (i.e., immunization, previous natural infection, inoculation, or transfer of protective antibodies)

Immune system:
The body’s very complex system (made of many organs and cells), which defends the body against infection, disease, and foreign substances

Immunity:
The condition of being immune or protected against infection, disease, and foreign substances

Immunization:
A process or procedure that increases an organism’s reaction to antigens, thereby improving its ability to resist or overcome infection

Incubation period:
The period of time after exposure to a disease that it takes for the host to display symptoms of that disease

Infection:
The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment from it.) A person with an infection has another organism (a “germ”) growing within him or her, drawing its nourishment from the person.

Infectious period:
The period of time during which an ill person may pass his or her disease to another

Microbial contamination:
The introduction of microbes into a person’s system

Microorganism:
Living organisms or living things (plants or animals) so small in size that they are only visible by the aid of a microscope

Outbreak:
Spread of disease, which occurs in a short period of time and in a limited geographic location (i.e., neighbourhood, community, school, or hospital)

Pandemic:
An outbreak of disease that spreads throughout the world

Pneumonia:
An infection of the deep, spongy parts of the lungs which can also be caused by viruses. Viral pneumonia causes cough with fever, chills and rapid breathing.

Respiratory system:
The part of the body that includes the organs through which air passes during breathing; also includes the structures which support these organs

Respiratory tract:
The upper respiratory tract includes the nose, sinuses, pharynx (throat), and larynx (voice box). The lower respiratory tract includes the trachea (windpipe), bronchial tubes (two branches from the windpipe), bronchioles (smaller bronchial tubes), and alveoli (tiny sacs in the lungs where the exchange of oxygen and carbon dioxide occurs).

Reye’s Syndrome:
An acute, potentially fatal metabolic disease seen primarily in children and characterized clinically by vomiting, hypoglycemia (low blood sugar), and confusion, which may progress to coma. Effects of the disease include cerebral edema (an accumulation of fluid between cells, causing swelling of the involved area) and fatty infiltration of the liver and other organs. (From Adams et al., Principles of Neurology, 6th ed., p. 1120).

Secretion:
Any liquid substance produced as a result of the activity of a gland, such as the salivary glands which manufacture saliva and secrete it into the mouth

Strain:
A specific biologic version of a microorganism (i.e. bacterium or virus). The identity of a strain is defined by its genetic makeup, or code; changing just one piece of the code produces a new strain.

Symptom:
A sign of disease. Having a fever is a symptom of influenza.

Syndrome:
A set of signs or a series of events occurring together that make up a disease or health problem

Vaccination:
Injection of a weakened or killed microorganism (bacterium or virus) given for the prevention or treatment of infectious diseases

Vaccine:
A product of weakened or killed microoorganism (bacterium or virus) given for the prevention or treatment of infectious diseases

Virus:
A tiny germ that grows and reproduces in living cells


Last Updated: 29 March 2017