Terms and Definitions


Aerosol: Particles (either solid or liquid) suspended in a gas, such as air.

Attenuated: The ability of the virus to cause disease has been blocked, although the virus is not killed.

Biopsy: Removal and examination, usually microscopic, of tissue from the living body.

Bronchopneumonia: Inflammation of the bronchi and lungs.

Cell Mediated Immunity: an immune response that does not involve antibodies, but rather the activation of macrophages and natural killer cells that directly kill cells infected by virus.

Conjunctiva: The delicate membrane lining the eyelids and covering parts of the eyeball.

Encephalitis: Inflammation of the brain

Enzymes: A protein that works to increase the rate of a reaction

Hyperemia: An excess of blood in a given location

Incubation Period: In interval between infection by a pathogenic infective agent, and the appearance of the first clinical signs of the disease.

MLV: Modified Live Vaccine. A vaccine prepared from live microorganisms that have lost their virulence but retained there ability to induce protective immunity.  

Morbidity: The condition of being diseased

Mucoid: Resembling mucous

Na´ve: In the context of immunity, an individual who has not been exposed to a specific agent.

Necrosis: Morphological changes that signal cell death

Ocular: Pertaining to the eye.

Pasteurella haemolytica: (also called Mannheimmia haemolytica). A genus of gram-negative rod-shaped bacteria.

Persistant shedders: Animals that do not show symptoms of the disease (i.e. are subclinical) but continue to shed the virus long after clinical signs disappear.

Purulent: Containing or forming pus

Pustule: A pus-containing lesion of the skin. Usually thin-walled and easily ruptured.

Rhinitis: Inflammation of the mucous membranes of the nose. Can be mild, chronic, or acute.

Rhinotracheitis: A combined inflammation of the mucosa of the nasal cavities and the trachea.

Serum: The clear, straw-colored liquid portion of plasma that does not contain blood cells.

Subclinical: When an animal is infected, but shows no overt signs of disease.

Systemic: Affecting/throughout the entire body.

Vulvovaginitis: Inflammation of the vulva and vagina.

All of these definitions come from Saunders Comprehensive Veterinary Dictionary 

(Blood, D., Gay, C., Studdert, V. 2007. Saunders Comprehensive Veterinary Dictionary. 3rd. Edition. Published by Elsevier. Toronto.)