Emerging & Re-emerging Infectiious Diseases
National Institute of Allergy and Infectious Diseases Home
skip navigation Main Getting Started Teacher's Guide Student Activities About NIH and NIAID
Glossary stack of books
skip glossary links glossary terms beginning with the letter A B C D E F G H I K L M N O P R S T V W

source: Location or object from which a pathogen is immediately transmitted to a host.

specific immune response: Collection of several immunological events in which lymphocytes recognize the presence of a particular antigen and act to eliminate it.

spirillum: Rigid, spiral-shaped bacterium.

spirochete: Flexible, spiral-shaped bacterium.

sporadic disease: Disease that occurs occasionally and at random intervals in a population.

superinfection: Bacterial or fungal infection that is resistant to the drug(s) being used to treat it.

T-cell: Lymphocyte derived from bone marrow stem cells that matures into an immunologically competent cell under the influence of the thymus. Involved in cell-mediated immune reactions.

TB skin test: Tuberculin hypersensitivity test to detect a current or past infection with Mycobacterium tuberculosis.

tetanus: Often fatal disease caused by the anaerobic, spore-forming bacterium Clostridium tetani. Characterized by muscle spasms and convulsions.

toxin: Microbial product or component that at low concentrations can injure a cell or organism.

transduction: Transfer of genes between bacteria by bacteriophages.

transformation: Mode of gene transfer in bacteria in which a piece of DNA in the environment is taken up by a bacterium and integrated into the bacterium's genome.

transposon: DNA segment that carries the genes required for transposition and can move from one place to another in the genome. Often carries genes unrelated to transposition as well.

tuberculosis: Infectious disease resulting from infection by a species of Mycobacterium. Infection is usually by inhalation, and the disease usually affects the lungs, although it can occur elsewhere in the body.

vaccination: Administration of a vaccine to stimulate an immune response.

vaccine: Preparation of killed microorganisms; living, weakened (attenuated) microorganisms; inactive or attenuated virus particles; inactivated bacterial toxins; or components (protein, carbohydrate, or nucleic acid) of the microorganism that are administered to stimulate an immune response. Vaccines protect an individual against the pathogenic agent or substance in the future.

vector: Living organism that transfers an infective agent from one host to another.

vector-borne transmission: Transmission of an infectious pathogen between hosts by way of a vector.

virulence: Degree or intensity of pathogenicity of an organism as indicated by mortality rate from the related disease and/or ability to invade tissues and cause disease.

virus: Infectious agent composed of a protein coat and a single type of nucleic acid. Lacks an independent metabolism and reproduces only within a host cell.

whooping cough (pertussis): Infectious disease of the respiratory tract caused by Bordetella pertussis.

back  

Copyright | Credits | Accessibility