Lecture 1: Intro to Disease Flashcards
What is Health (Reference to livestock)?
Welfare, Production, and Reproduction
What is the traditional definition of Disease?
A finite abnormality of structure or function with an identifiable pathological basis and recognizable clinical signs
What are clinical signs? What is an example?
Direct observation of the patient (objective). Ex. laboured breathing, limping
What is the now broadened definition of Disease?
Now includes subclinical disease, suboptimal production and welfare
Define: Subclinical disease, Clinical disease and sub-optimal production.
Subclinical disease: Not visible but measurable in some way. EX somatic cell count
Clinical Disease: Overt visible signs EX. Diarrhea
Sub-optimal production: Below what is expected for the breed, industry or genetic line
What is the acronym for the classification of Disease?
D- Degenerative
A- Anomalous
M-Metabolic
N-Neoplasm/Neoplastic
I-Infectious
T-Traumatic or Toxic
What does degenerative mean in terms of the classification of disease?
Structure is altered by age, use or disuse, or biochemical changes. Ex Arthritis
What does Anomalous mean in terms of the classification of disease?
Abnormal structure or function that is congenital and may be genetic. E Cleft palate, atresia ani (lacking a rectum)
What does metabolic mean in terms of the classification of disease?
Due to nutrition, toxins or hormonal activity that alters normal metabolism. EX Milk fever, ketosis HINT: THINK DAIRY
What does Neoplasm/neoplastic mean in terms of the classification of disease?
Abnormal growth of cells at the expense of normal tissue structure and function. EX lymphosarcoma and eye cancer
What does infectious mean in terms of the classification of disease?
Microorganisms invade the body and damage normal structure and function. EX Mycoplasma hyopnemonia causing pneumonia in pigs.
What does trauma and toxic mean in terms of the classification of disease?
Mechanical injury EX broken bones
exogenous substance gains access to the system which causes damage to structure leading dysfunction.
What is a pathogen and what part of DAMNIT is it considered?
Any disease-producing (or infectious) microorganism or material ie virus, bacteria and fungus.
A pathogen is considered infectious.
What is Etiology?
Study of the causes of disease. An Etiologic agent = causative agent of disease but NOT= “the cause”
What is the Koch’s Postulates process?
Sick animal –> Isolate a Pathogen –> Infect healthy animal –> Cause same disease –> Re-isolate same pathogen
What is pathogenesis?
The development or process of a disease OR The process by which a pathogen produces a disease
HINT: Pathogenesis: Path: pathogen genesis: formation
What are the infectious causes/agents of disease? Examples?
Bacteria
Viruses
Prions (cause BSE AKA mad cow)
Mycotic (fungal ringworm)
Parasites (3 types Intracellular, Internal, external)
What are 2 ways disease transmission can be described?
- How the pathogen is exchanged between hosts
- Populations the pathogen is exchanged between
What is the difference between horizontal and vertical disease transmission?
Horizontal is between the same generation ex the same pen and vertical is between animal of a different generation ex mother to offspring.
What are the modes of disease transmission?
Direct
Fomites-Inanimate objects, does not infect-passive carrier
Vector-Invertebrate animal required for agent lifecycle and transmission
Infectious secretions or excretions- Resp droplets, saliva, put exudate, faces and urine
What is the Epidemiological Triad? Does an infectious agent present mean that a disease is also present?
Host
Agent Environment
No.
What are the 2 different concepts related to Triad?
- Tipping point- Health with protective factors balancing with disease risk factors
2.The iceberg concept- clinical perception is less then the actual herd problem
