Terms and Definitions

Acidosis - A pathological condition resulting from the accumulation of acid, or the depletion of alkaline (bicarbonate) reserves in the blood and body tissues.  Bicarbonate can be lost with diarrhea and this can lead to a metabolic acidosis, which if not corrected can be a factor in an animal feeling ill, or even contributing to it’s death.  11

Acute -  A characteristic of a disease or infection that has severe signs and a short course of 12 to 24 hours.

Alimentary tract - all organs making up the route taken by food as it passes through the body from mouth to anus; it comprises the esophagus, stomach and small and large intestines.  Also called the digestive tract.11

Alveolar macrophages – Rounded, granular, mononuclear phagocytes within the alveoli of the lungs that ingest inhaled particulate matter.  11

Anorexia - Occurs when an animal stops eating.

Antibody - Specialized proteins found in the blood that are produced in response to infectious pathogens.  These proteins help protect the animal from disease caused by infection by neutralizing the antigen. 11

Antigen – Any substance that is capable of inducing a specific immune response in which antibodies attempt to neutralize.  It is usually a specific protein on the surface of a pathogen responsible for attaching that pathogen to the cell it is going to attack, but it may also be a toxin or another foreign protein.  11

Attenuated – This means the virus cannot cause disease but it can reproduce in the body cells and stimulate immunity.  Attenuation is done in order to make a vaccine safe to administer. 11

Bioassay – Determination of the active power of a drug sample by comparing its effects on a live animal or an isolated organ preparation with those of a reference standard. 11

Bovine Respiratory Disease Complex – A group of undifferentiated diseases of young cattle characterized by dyspnea, coughing, nasal discharge, evidence of pneumonia when listening to the lungs, and non-specific signs as a result of toxemia of infection and tissue destruction.  11

Bronchiectasis – chronic dilation of the bronchi and bronchioles (air passages in lungs) with secondary infection, usually involving the dependent (lower parts drained by gravity) parts of the lung.  11

Bronchiolitis - Inflammation of the bronchioles (smaller airways in the lungs).11

Carriers -  An animal which harbors a disease organism in its body without showing clinical signs, thus acting as a "carrier" or distributor of infection. 11

Cell-mediated immunity - dependent of T-lymphocytes which are sensitized by first exposure to a specific antigen.  Subsequent exposure stimulates the release of a group of substances known as lymphokines, such as interferon, and interleukins as well as direct killing by cytotoxic T lymphocytes.  11

Chronic -  A characteristic of a disease or infection that persists for a long time, usually longer than one week, and progresses slowly.

Clinical disease – This means that the animal is showing obvious signs to show that it is diseased. 

CNS (Central Nervous System) – This nervous system includes the brain and the spinal cord.

Colostral Antibodies - Protective proteins found in colostrum that provide passive immunity to newborn calves.  These molecules are quite large and as such, have to be absorbed by the calf during the first few hours of birth, before the gut closes to them. 

Conjunctivitis - Inflammation of the conjunctiva which is the delicate membrane lining the eyelids and covering parts of the eyeball. 11

Coronitis – Inflammation of the skin at the coronet of the hooves; a cause of lamness.  11

Culture – the propagation of microorganisms in special media conducive to their growth. 11

Cytopathic -  Pertaining to or characterized by pathologic changes in cells. 11

Dorsal root ganglion – A group of nerve cell bodies arising to the side of the spinal cord that transmits incoming information to the spinal cord and up to the brain for processing. 

Dyspnea – Labored or difficult breathing. 11

Ecchymosis – a hemorrhagic spot, larger than a petechia, in the skin or mucus membrane, forming a non-elevated, rounded or irregular, blue or purplish patch.  11

ELISA (enzyme linked immunosorbent assay) - A type of primary binding test used to detect and measure either antibody or antigen.  Either antibody or antigen is bound to a solid surface and a second antibody to which an enzyme is conjugated is added, followed by a substrate for the enzyme.  11

Encephalitis - Inflammation of the brain. 

Endemic – Present in a predictable, continuous pattern in an animal community at all times; said of a disease which is clustered in space, but not in time.  11

Endometritis - Inflammation of the inner layer of the uterus.

Enteritis – Inflammation of the inner layer of the intestine resulting in diarrhea, (sometimes bloody) dehydration and electrolyte loss and imbalance.  11

Enteropathogens - Infectious agents causing disease in the digestive tract.

Enzootic pneumonia – A group of pneumonic diseases which affect young animals.  11

Epitope – A structural component of an antigen against which immune responses are made and to which antibody or T cell receptors bind; an antigen such as a protein has many epitopes.  11

FAT (Fluorescence Antibody Test) – A technique to bind one end of an antibody with a fluorescent dye and adding that conjugated antibody to a tissue and allowing it to bind to an antigen.  The antigen-antibody complex is made visible under a special microscope for detecting fluorescent dye.  If the dye is visible it means that the antigen was present in the tissue.   11

Genotype - the entire genetic constitution of an individual.  11

Hemagglutination – Some viruses have the capability to bind red blood cells together or to make them hemagglutinate.  This can be used to quantify a virus if it has this particular characteristic; not all viruses do.  For example, a certain amount of virus will be able to cause hemagglutination, therefore, as the amount of red blood cells stays the same, but the amount of virus decreases, the less ability the virus will have to cause hemagglutination.  9

Humoral Immunity - This type of immunity is based on antibody produced by antigen specific B lymphocytes. 11

IHC (Immunohistochemistry) – Immunohistochemistry is a method of analyzing and identifying cell types based on the binding of antibodies to specific components of the cell.  It is sometimes referred to as immunocytochemistry. 10

Immunocompetent –An animal is said to be immunocompetent if it has the capacity to develop an immune response following exposure to antigen. 11

Immunofluorescence - The labeling of antigens and antibodies with fluorescent dyes to make them more visible.  17

Immunoperoxidase staining – A technique of histological (microscopic viewing of cells) staining that provides details about the structure of the cell and immunological identification.  It is essentially the same as immunofluorescence  techniques only it uses peroxidase conjugated to antibodies instead of fluorescent dyes.  11

Immunosuppressant – An animal is said to be immunosuppressed if it does NOT have the capacity to develop an immune response following exposure to antigen. 11

Immunotolerant – An animal is said to be immunotolerant if it has specific non-reactivity to a particular antigen, i.e. self-antigens, which is capable under other conditions of inducing an immune response.  11

Incubation period – The interval between the infection of an animal with a pathogen and the appearance of the first clinical signs of disease.  11

Inflammation – A localized protective response elicited by injury or destruction of tissues, which serves to destroy, dilute, or wall off both the injurious agent and the injured tissue.  11 

Intranasal – Vaccine administered into the nose. 

Isolate – A population of microorganisms that has been obtained in a pure culture form a field case or location.  11

Lacrimal – Pertaining to tears.  11

Laminitis – Inflammation of a part of the hoof that can lead to lameness.

Laryngitis - Inflammation of the larynx.

Latent - A dormant, or concealed, infection that has the potential to produce clinical symptoms at sporadic intervals.  11

Lethargy - A condition of drowsiness or indifference.  11

Leukopenia – A reduction in the number of white blood cells in the blood.  11

Maternal antibodies - Antibodies that are passively transferred from the dam to the fetus or newborn, through the placenta or via colostrum.  11

Morbidity – The condition of being diseased.  11

Mortality – Death as a statistic.  11

Necrosis - Cell death caused by enzymatic degradation.  11

Neonatal – A newborn animal.  11

Neutralize – This is done when an antibody attaches to an antigen and renders it neutral.  11

Non-cytopathic - Producing no pathological changes in cells.  11

Non-suppurative - No pus usually indicating that viruses are involved and not bacteria.

Obligate parasite – A parasite that is entirely dependently upon its host for survival.  11

Ocular - Pertaining to the eye.

Opsonization – The rendering of bacteria and other foreign substances subject to phagocytosis.

Organogenesis – The period in which the fetus undergoes the development of organs.  11

Ovaritis – Inflammation of the ovary. 

Parenteral - Not through the alimentary canal, e.g. by subcutaneous, intramuscular, intrasternal, or intravenous injection. 11

Parturition – To give birth to a calf.

Passive transfer – The transfer of antibodies from the mother (donor) to the calf (recipient) for temporary immunity.  Antibodies can be transferred through colostral antibodies or through the placenta.  11

Pathogen – A disease producing agent or microorganism.  11

PCR (Polymerase Chain Reaction) – A technique for amplifying DNA sequences in vitro by separating the DNA into two strands and incubating it with oligonucleotide primers and DNA polymerase. It can amplify a specific sequence of DNA by as many as one billion times and is important in biotechnology, forensics, medicine, and genetic research.  16

Petechia – A minute, pinpoint, non-raised, perfectly round, purplish red spot caused by intradermal or submucosal hemorrhage, which later turns blue or yellow.  11

– Very acute; a duration of a few hours only.  11

Phagocyte – Any cell that ingests microorganisms or other cells and foreign particles.  11

Phagocytosis – The engulfing of microorganisms or other cells and foreign particles by phagocytes.  11

Pleural Pneumonia - Inflammation of the tissues surrounding the lungs that results in difficulty breathing.  11

Pleuritis – Inflammation of the tissues surrounding the lung and lining the thoracic cavity.  11

Pneumonic pasteurellosis  (shipping fever) – See Bovine Respiratory Disease Complex; it is a disease that is predisposed by the stress of shipping, usually to the feedlot, and by the mixing of cattle from many different places.

Polypnea – Increased rate of respiration.  11

Pulmonary abscess – An abscess in the lungs.   

Pyrexia – Fever.

Rhinitis – Inflammation of the inner membranes (mucus membranes) of the nose.  11

Secondary bacterial infection – This infection occurs when there is a primary infection, usually caused by a virus or physical damage, in an area and that area becomes predisposed to developing a  bacterial infection.

Serology - The conduct of antigen-antibody reactions in vitro.  11

Seropostive -  An animal is seropositive for a pathogen if it has antibodies in it’s serum for antigens of that pathogen.

Serotype – All isolates of a virus that can be neutralized by the same serum antibodies.  9

Serous – Pertaining to serum.  11

Serum – The term usually refers to blood serum, the clear, straw-colored, liquid portion of the plasma that does not contain fibrinogen or blood cells, and remains fluid after clotting blood.  11

Shedding – Excretion of the virus.

Subclinical -   Without clinical signs.  Usually describes the early stages or a very mild form of a disease.  11

Subunit vaccine - Contains only one or more of the antigens of the pathogen necessary to evoke a protective immune response, and lacks the components that might cause unwanted side-effects. 1

Tachypnea – Very rapid respirations.  11

Tracheitis -  Inflammation of the trachea. 

Transient infection – An infection that passes with time. 

Transmission -  The transfer of an infection from one animal to another.

Type II pneumoncyte – A type of alveolar epithelial cell that produces and secretes surfactant(a fluid in the lungs that reduces the surface tension of pulmonary fluids and thus contributes to the elastic properties of the lungs) and provides replacement for type I pneumocytes.  11

Ubiquitous – Found everywhere.

Viremia - The presence of viruses in the blood.  11

Virulence – The degree of pathogenicity of a microorganism as indicated by the case fatality rate and/or its ability to invade the tissues of the host; the competence of any infectious agent to produce pathological effects.  11

Virus isolation - Isolating the virus with tissue cultures. 1

Wild strain - The strain that causes natural infection as opposed to an infection caused by vaccination.

Zona pellucida – The transparent, noncellular, secreted layer surrounding the ovum.  11

Zoonotic risk – Risk of transmission of a pathogen between humans and animals.