View
32
Download
0
Category
Preview:
DESCRIPTION
Causes of Disease. 4-H Veterinary Science Extension Veterinary Medicine Texas AgriLife Extension Service College of Veterinary Medicine and Biomedical Science Texas A&M System http://aevm.tamu.edu. Objectives. Distinguish between infectious and non-infectious causes of disease - PowerPoint PPT Presentation
Citation preview
Causes of Disease
4-H Veterinary ScienceExtension Veterinary Medicine
Texas AgriLife Extension ServiceCollege of Veterinary Medicine and Biomedical Science
Texas A&M Systemhttp://aevm.tamu.edu
Objectives
Distinguish between infectious and non-infectious causes of disease
Discuss risk factors Discuss primary cause factors Discuss secondary cause factors
Infectious Diseases
Infectious disease An illness due to a specific infectious agent or
its toxic products that arises through transmission of that agent or its products from an infected person, animal or reservoir to a susceptible host, either directly or indirectly
Agents involved Germs
Bacteria Viruses Fungi Rickettsiae
Helminths Protozoa Arthropods
Damage caused Feed off of body tissue Reproduce in tissue Release toxins Pressure
Reproduction Lag phase
Usually incubation period where organism is settling in to new surrounding
Growth phase Exponential growth is rapid
Plateau phase Growth = Death
Time
Number of Organisms
Lag Phase
Growth Phase
Plateau Phase
Lag phase maybe long Non-disease dormancy or latency
multiple when conditions are optimal or when organism is ready
May break if bacteria is in stressful environment
Bacteria and virus are precipitated by stress Ex. Anthrax go into dormancy (spore form) when
exposed to oxygen, once in anaerobic environment, bacteria multiply and cause fatal disease
Causes disease
Non-Infectious Disease
Disease cause Dysfunction or disorder of reproductive
disease Example - hypo/hyper-thyroidism
Nutritional deficiencies or imbalances Example - copper toxicity - damage liver
Chemical and plant poisoning Example - acorns and green tomatoes
Physical injuries and stress
Causal pathway Variables present
A
G F
D
E
CB
H
C
D
E
F
A
B
Diseased Non-Diseased
Primary Cause ALWAYS present when occurs and Risk factors increase or decrease probability
of disease in individual Disease
Example - not washing hands after using restroom
Dysfunction Example - cryptorchidism
Disorder Example - type 1 diabetes - body does not
produce enough insulin
Secondary Causes
Primary cause not as evident Secondary is noticeable when individual is
sick Need tissue damage from primary cause Invade and multiply
Dividing Bacteria Video
Risk Factors
Causative factors Increase chances of getting sick Examples
Overcrowding Pollution Weather Inbreeding
Protective factors Decrease chances of getting sick Examples
Vaccination Husbandry Crossbreeding Good management practices
Recommended