ANSC 100

Any deviation from or interruption of the normal structure or function of any body part, organ or system (manifested by characteristic set of symptoms and signs. Etiology, pathology and prognosis may be known or unknown)

A set of symptoms occuring together, a symptom complex

An agent or microorganism possessing the ability to cause a disease in a given animal in a given environment (Examples: infectious organisms, sometimes carcinogens, toxins)

Causes diseases nearly every time it invades a healthy animal, even in low numbers

Low virulence and causes diseases only if administered in high doses or immune defenses are impaired

Study of the events and reactions particularly changes in body tissues and organs, occuring in the development of disease

The determination and study of the factors that contribute to the production of disease.

Determination of the nature of a case of a disease. (Note: does not necessarily require determination of etiology)

A forecast of the probable course and outcome of a disease

The quality of producing or the abilty to produce pathogolic changes or disease

The degree of pathogenicity of a microorganism, as determined by case fatality rates and/or ability to invade the tissues of the host, evode body's defenses and cause disease

Any foreign substance (protein, etc) that can bind to specific lymphocyte receptors and so induce induce an immune response

An immunoglobulin molecule synthesized on exposure to an antigen, which can combine (attach) specifically with that antigen

Purpose is to impair entry of microogranisms through the epithelium into body (physical barriers, innate immunity, inflammation)

• Purpose is the deal with microorganisms that gain entry into body and escape primary defenses
• The immune system: Cell-Mediated Immunity
• Humoral Immunity

• antibody production (humoral immunity); cell-mediated immunity
• 5 Major components:
• 1 Cells that trap and process antigen and then present if for recognition to the cells of the immune system.
• 2 Cells that have receptors fro the processed antigen.  These cells can bind and respond to the antigen (antigen-sensitive cells)
• 3 Cells that, once activated by antigen, will produce specific antibodies, or will participate in the cell-mediated immune responses against the antigen (effector cells)
• 4 Cells that will retain the memory of the event and react rapidly to that specific antigen if it is encountered at a later time
• 5 Cells that regulate this response and ensure that is functions at an appropriate level (inhibit immune responses)

• Killed up to 1/2 M Europeans per year in end of 18th century
• In 1967 WHO estimated 15 M contracted and 2 M died/year
• Declared eradicated in1979
• 1796 Edward Jenner "made" first vaccine using cow pox.  In 1800, probably the world's first community use of smallpox vaccine in Newfoundland
• The vaccine did not eradicate the disease alone, also required aggressive epidemiology and quarantine response to outbreaks

• Louis Pasteur (1879), gave aged P. multocida to a chicken, then gave that chicken and a normal chicken the fresh P. multocida. Only the normal chicken died
• Also developed anthrax and rabies vaccine

• An Innate Mechanism
• Exposure to: Microbial invasion, trauma, heat, chemicals
• Results in Tissue Damage, releasing Alarmins.... and/or
• Toll-Like Receptors recognize pathogen-associated molecular patterns (PAMPS) which are highly conserved molecules (such as Lipopoysaccharide or Lipoteichoic Acids) that are found on surface of many different microorganisms
• TLRs are Alarmins trigger innate immune defenses of Sentinel Cells - result is inflammation
• Vasoactive Molecules or Sytokines are released activating vasculare changes, phagocytic cell activity, and systemic responses
• These activate neutrophils and macrophages, resulting in the killing of bacteria, and tissue repair processes

• Redness (rubor)
• Heat (calor)
• Pain (dolar)
• Swelling (tumor)
• Loss of function (functio laesa)

Use "-itis" to indicate inflammation

• Sudden onset
• Short duration
• Does not imply severity
• May be mild or severe

• Onset slow
• Long lasting
• Often results in impaired function
• May begin with acute episode that does not resolve, or recurs

• White Blood cells (leukocytes) form essential part of secondary defenses
• Granulocytes
• Mononuclear cells

• Antibodies - soluble antigen receptors
• Antibody proteins are known as "immunoglobulins"
• 5 types of immunoglobulins in mammals: IgG, IgM, IgA, IgE, IgD
• Produced by "B cells" - a type of lymphocyte
• Ab's are very specific to particular invading material - the "antigen"
• An "antigen" must be recognized as foreign
• Anitgen receptors must reliably bind foreign antigens on the first encounter
• Achieved by scrambling and rearranging the peptide sequences that comprise the antigen-binding site (millions of conformations), allows them to bind to almost any invading microorganism

• Intial invasion (infection) stimulates production of proteins called "antibodies" by plasma cells (a type of lymphocyte)
• Antibodies bind specifically to antigen and hasten its destruction or elimination by various types of lymphocytes and other cells and their products
• Stimulates production of "memory" cells to initiate a quicker and larger response the next time the antigen in encountered

• Active:
• Immunity produced by the body
• In response to an administration of an antigen
• Triggers the body's immune response (and memory)
• Passive
• Protection of individual by administering antibodies produced in another individual
• No immune response triggered to the antigen in the recipient
• No memory

• Exposure to, or vaccination with live, attenuated or dead infectious agent to produce an immune response
• Disadvantage: Protection is nopt vonferred immediately and often requires "boosters"
• Advantage: once established immunity is long-lasting and capable of re-stimulation

• Production of temporary immunity by administration of preformed antibodies from a resistant to a susceptible animal (gives immediate protection but antibodies are gradually broken down and immunity wanes)
• Can block the development of active immunity until passive immunity drops off

• Many routes
• Intramuscular
• Subcutaneous
• Oral
• Intranasal
• Eyedrops

• Recognition and elimination of foreign proteins (antigens) without damaging normal cells and tisues.
• Failures result in: tolerance (failure to fight infection), automminue disease (reaction against self), or allergic reaction (exaggerated reaction to non-pathogens)

• Stress
• Body Condition
• Parasitism
• Nutrition (trace mineral deficiencies: copper, selenium, zinc or manganese)

Healthy animal, effective vaccine given properly

• 1. Incubating disease at the time of vaccination
• 2. Something happened to the vaccine to make it ineffective
• 3. Physiological status of the vaccinated animal may make it less responsive or unresponsive to the vaccine
• 4 The host may be exposed to an overwhelming amount of the infectious agent

• Antigenic components
• Homologous Antigens
• Heterologous Antigens
• CROSS PROTECTION
• Adjuvants

• Environmental/storage stress
• Improper injection equipment
• Sterilization practices
• Mixing products in syringes
• Route of injection
• Aseptic technique

• Maternal Blockade
• Immune suppression
• Concurrent diseases
• Drugs (corticosteroids)
• Nutritional status
• Age
• Hormones
• Incubation of disease
• Stress, stress, stress

• Disease that is caused by a living agent (bacteria, viruses, protozo, fungi)
• Although an infectious disease may or may not be contagious - most are transmissible (tetanus)

Denotes the disturbances caused by the entrance, growth & activity of the disease causing agent in the body (ie. abnormal body temp, inflammtion, loss of appetite, abnormal breathing, abortion...)

• 1. Presence of a pathogenic organism
• 2. The intervening agents (vector or fomite)
• 3. A portal of entry into the susceptible animal

• Bacteria
• Viruses
• Protozoa
• Fungi
• Multicellular parasites

• Inanimate vectors or fomites
• -Feed and water
• -Transport vehicles, bedding stalls, troughs
• -Needle & syringes
• Animate vectors
• -arthropods - flies, ticks, lice..
• -mammals - rodents, wild animals, other farm animals, humans

• Routes or pathways into the body often depends on the infectious agent and the vector involved.
• The most common portals of entry into the body include: into cuts, punctures or abrasions of the skin; through mucous linings - mouth, eyes, respiratory tract, gastrointestinal tract, uro-genital tract

• An animal (host) will inevitably be exposed to pathogenic organisms (agent)
• An animal capable of warding off a particular pathogen are considered `resistant`
• Animals in good health normally have primary and secondary defenses that maintian their disease resistance

• Collection of statistical tools used to elucidate the associations of exposures to health outcomes
• Discover and establish causal relationships
• Correlation does not eqaul causation

• Dose (number of bacteria or virus particles that challenge the animal)
• Pathogenicity (organism's ability to reach the animal, invade and infect, and multiply enough to cause disease)(Invasiveness: the organism's ability to spread from the initial invasion site or to gain entry to the circulatory system)(Production of harmful substances: pathogenicity of an organism is often due to toxins or enzymes it produces that interfere with the function or metabolism of the animal)
• Immune Status (the animal's ability to fight off the disease organism, both primary and secondary defenses).

Interactions through management between Host (animal), agent, and environment