What is disease?
alteration of the state of the body or some of its parts which interrupts or disturbs the proper performance of bodily functions
any change in the body or its function as perceived by the patient - may only be observed by the patient
What are the causes of non-infectious diseases?
- mechanical injury
- genetic - congenital, developmental
What is contamination?
presence of microorganisms in the body
What is infection?
presence and replication of microorganisms in the body, which may cause tissue injury or disease
Define clinical signs.
objective evidence, manifestations of disease apparent to the observer
What are the different types of infections?
transmitted from one animal to another
not transmitted to other animals
transmitted from animal to human or human to animal
internal or external
What are the methods of spread of disease?
- direct contact
- food and water
- resident flora
- laboratory exposure
What are the different classifications of disease according to time?
- affects animal extremely rapidly
- often dies before clinical signs are seen
- arises within a few hours and is resolved within days or a few weeks
- either death or recovery
- development of clinical signs takes 1 - 3 weeks
- either death or recovery
- insidious onset - weeks, months, or years
- often cannot pinpoint exactly when the animal became ill
- self - corrects in a few days
- may never determine the causes
- may become a latent infection - carrier state
What are the properties of infectious agents?
- bacterial enzymes
- toxin production
What is virulence?
- the capacity of a microorganism to cause disease
- ability to grow and thrive in the environment provided by the host
- can invade and cause lesions
- destroys cells by - presence, secretion, and/or host response
What does virulence result in?
- local infections
- systemic infections
What are the different systemic infections?
Yew poisoning is an example of what type of disease?
Milk fever is an example of what type of disease?
Panleukopenia is an example of what type of disease?
Parvovirus is an example of what type of disease?
Intestinal obstruction is an example of what type of disease?
Hip dysplasia is an example of what type of disease?
Bacterial enzymes is an important factors in _____.
What are the different types of bacterial enzymes?
What does hyaluronidase do?
- breaks down hyaluronic acid - tissue "glue"
- makes it more "liquid-y" between cells, easier for microorganisms to spread
What does staphylokinase do?
- produced by certain staphlyococci
- lyses fibrin
What does streptolysin do?
a hemolysin (breaks down red blood cells) produced by certain streptococci
What are toxins?
chemical substances destructive to the body, "poisons"
What are the two types of toxins?
What are endotoxins?
toxins produced by bacterial cells that are released when the bacteria dies
What is the most common endotoxin?
Endotoxins are a component of gram _____ bacterial cell wall
What are the clinical signs of endotoxemia?
What are the characteristics of endotoxins?
What are true toxins?
What are exotoxins produced and released by?
What are characteristics of exotoxins?
- highly poisonous
- excellent antigens
What are the different host defenses against disease?
- anatomical barriers
- reflex barriers
- phagocytosis by neutorphils and macrophages
- antitoxin production
- fever, inflammation
- immune system
What is the primary defense against disease?
What are the different anatomical barriers?
- mucous membranes
- low pH of stomach acid
- sebaceous glands
- perspiration, tears, saliva
What are the different mucous membranes?
- respiratory tract
- gastrointestinal tract
- genitourinary tracts
What type of properties do sebaceous glands have?
antifungal and antibacterial properties
How does perspiration, tears, and saliva protect against diseases?
have lysozymes that attack the cell walls of certain bacteria - mild antiseptic effect
What are the different reflex barriers?
What are the different biochemical defenses against disease?
enzyme systems such as lysozymes in WBCs
What is antitoxin production?
an antibody formed to fight a specific toxin
What is interferon?
a type of protein produced by cells exposed to a virus, bacteria, antigens, etc - having the ability to inhibit viral replications and having other immune functions
What is a fever?
a rise in body temperature above normal in response to disease
What typically causes a fever?
What does a high temperature associated with a fever do?
may inhibit growth of virus or bacteria
Other than infectious disease, what can cause a fever?
What is pyrogen?
a fever-causing substance - from the infectious agent or from host body cells
What is considered a dangerous fever in small animals?
What are the five cardinal signs of inflammation?
- heat - "color"
- redness - "rubor"
- swelling - "tumor"
- pain - "dolor"
- loss of function
What does inflammation cause?
- vasodilation and increased permeability of blood vessels
- swelling of tissues due to fluid leakage from blood
- increased local temperature due to vasodilation
- pain from swelling - migration of WBCs through vessel walls