Glossary of Terms
Below you will find an alphabetical listing of common terms used in articles in the Special Pathogen Branch web site. These terms occur frequently in epidemiological and health prevention literature.
List of Terms
A fine mist or spray which contains minute particles.
Proteins produced by an organism's immune system to recognize foreign substances.
Any substance that stimulates an immune response by the body. The immune system recognizes such substances as being foreign, and produces cellular antibodies to fight them. Antigen/antibody response is an important part of a person's immunity to disease.
A quantitative or qualitative evaluation, or test, of a substance. Frequently used to describe tests of the presence or concentration of infectious agents, antibodies, etc.
Specific combinations of work practices, safety equipment, and facilities, which are designed to minimize the exposure of workers and the environment to infectious agents. Biosafety level 1 applies to agents that do not ordinarily cause human disease. Biosafety level 2 is appropriate for agents that can cause human disease, but whose potential for transmission is limited. Biosafety level 3 applies to agents that may be transmitted by the respiratory route which can cause serious infection. Biosafety level 4 is used for the diagnosis of exotic agents that pose a high risk of life-threatening disease, which may be transmitted by the aerosol route and for which there is no vaccine or therapy.
A person or animal that harbors a specific infectious agent without visible symptoms of the disease. A carrier acts as a potential source of infection.
The number of cases of a disease ending in death compared to the number of cases of the disease. Usually expressed as a percentage. While deaths from other diseases are often expressed as mortality rates, VSPB normally uses case-fatality proportions. This is due to the fact that rates include a time determinant - for example, 100 deaths per 1000 cases per year. However, the diseases VSPB works with break out sporadically, and occur as brief epidemics.
case-to-infection ratio or proportion:
The number of cases of a disease (in humans) compared to the number of infections with the agent that causes the disease (in humans).
Formally speaking, a disease is the condition in which the functioning of the body or a part of the body is interfered with or damaged. In a person with an infectious disease, the infectious agent that has entered the body causes it to function abnormally in some way or ways. The type of abnormal functioning that occurs is the disease. Usually the body will show some signs and symptoms of the problems it is having with functioning. Disease should not be confused with infection.
ELISA (enzyme-linked-immunosorbent serologic assay):
A technique that relies on an enzymatic conversion reaction. It is used to detect the presence of specific substances, such as enzymes, viruses, antibodies or bacteria.
Disease that is widespread in a given population.
A disease which is constantly present in the animal community, but only occurs in a small number of cases.
The occurrence of cases of an illness in a community or region which is in excess of the number of cases normally expected for that disease in that area at that time.
An outbreak or epidemic of disease in animal populations.
An organism in which a parasite lives and by which it is nourished.
One of many antibodies present in blood serum which is usually indicative of a recent or remote infection. IgG is most prevalent about 3 weeks after an infection begins.
One of many antibodies present in blood serum which is usually indicative of an acute infection.
A type of assay in which specific antigens are made visible by the use of fluorescent dye or enzyme markers.
The entry and development of an infectious agent in the body of a person or animal. In an apparent "manifest" infection, the infected person outwardly appears to be sick. In an inapparent infection, there is no outward sign that an infectious agent has entered that person at all. For example, although humans have become infected with Ebola-Reston, a species of Ebola virus, they have not shown any sign of illness. By contrast, in recorded outbreaks of Ebola hemorrhagic fever caused by Ebola-Zaire, another species of Ebola virus, severe illness followed infection with the virus, and a great proportion of the case-patients died. Infection should not be confused with disease.
An infection occurring in a patient which is acquired at a hospital or other healthcare facility. Commonly called a cross infection.
report of a disease:
An official report that notifies an appropriate health authority of the occurrence of a disease in a human or in an animal. Human diseases usually are reported first to the local health authority, such as a county health department.
Any person, animal, arthropod, plant, soil or substance in which an infective agent normally lives and multiplies. The infectious agent primarily depends on the reservoir for its survival.
RT-PCR (reverse transcriptase polymerase chain reaction):
Powerful technique for producing millions of copies of specific parts of the genetic code of an organism so that it may be readily analyzed. More specifically, RT-PCR produces copies of a specific region of complementary DNA that has been converted from RNA. The technique is often used to help in the identification of an infectious agent.
surveillance of disease:
The ongoing systematic collection and analysis of data and the provision of information which leads to action being taken to prevent and control an infectious disease.
transmission of infectious agents (such as a virus):
Any mechanism through which an infectious agent, such as a virus, is spread from a reservoir (or source) to a human being. Usually each type of infectious agent is spread by only one or a few of the different mechanisms.
There are several types of transmission mechanisms:
A carrier which transmits infective agent from one host to another.
A minute infectious agent.
zoonotic disease or infection:
An infection or infectious disease that may be transmitted from vertebrate animals (such as a rodent) to humans.
|This page last reviewed July 31, 2012|
Content source: Centers for Disease Control and Prevention