Prevention & Control Flashcards
Two questions for vaccine use:
Can the vaccine control the disease?
Do risks of vaccination outweigh the benefits?
Examples of passive immunity:
Colostrum
Transplacental
Immune Serum Administration (Like tetanus antitoxin)
Examples of Active Immunity:
Natural infection
Vaccination
How do they make modified live vaccines?
Grow it in cell culture that lessens its virulence
Advantages of Modified Live Vaccines-
Produces good immune response with limited doses
Adjuvants aren’t necessary
Less chance for hypersensitivity
Cellular & Humoral Response
Disadvantages of Modified Live Vaccine:
May induce dz
Usually not rec. in pregnant animals
Risk of contamination
Immunosuppression
Handling requirements
Advantages of Inactivated Vaccines:
Stable in storage
Safe-unlikely to cause disease
Types of Inactivated vaccines:
Bacterins
Toxoids
Killed Virus
Disadvantages of Inactivated vaccines:
Multiple doses required
Immunity is short lived
Anaphylaxis
Expensive
Rxn to Adjuvants
Variable cellular immunity
Routes of Vaccine Administration:
Intranasal
Oral
Parenteral- SQ, IM, ID
Intranasal Vaccine provides what type of immunity?
Local & Systemic
Oral Vaccine provides what type of immunity?
Local & Systemic
Parenteral Vaccine provides what type of immunity?
Systemic ONLY
What is the rule of thumb for food animal vaccine withdrawal times?
21 days, but READ the label
What is the benefit of intranasal vaccines?
reduces shedding of organisms
(especially of ones that the animal may already have)
Where do all the Food animals get their vaccines:
Subcutaneous in cervical region
Axillary space in SR & Pigs
Flank if pig < 40lbs
Where do equine get their vaccines:
Intramuscular
Cervical Muscles
Pectoral, Semimem & Semiten
Examples of increased times of exposure:
Seasons
Congregation of Animals
Increased times of stress
Pregnancy
Disease prevention:
Proactive approach to maintain the health of animals prior to hazard exposure
Disease Control:
Once disease is detected, actions taken to prevent new cases of disease, detect new cases as early as possible, and to limit disease impact
Factors that contribute to health & disease:
Nutrition, Immunity, Environment, Genetics
Disease outcomes are commonly ___________
multifactorial
Intense genetic selection effect on dz outcomes:
May reduce survivability by altering disease resistance
Epigenetics:
The study of how environment can cause changes in how genes are expressed
Herd Immunity:
The resistance to the spread of contagious disease through the population if a high proportion of the population is immune
How is herd immunity accomplished (3)
Natural Exposure
Controlled Exposure
Vaccination
Transmission Rate:
Contact rate x Infectivity
Contact Rate:
quantifies interaction between hosts or between hosts and environment
Infectivity:
the probability of infection given contact
What is contact rate determined by:
behavior, movement patterns, and properties of the environment
What is infectivity influenced by?
Virulence of pathogen
Immune status of host
What does transmission rate determine?
how many cases you will see over what time period
Instances to use controlled exposure:
When Vaccines are non-existent or poorly effective
When clinical disease is age dependent & severe/acute/fatal disease can be avoided with early exposure
Specific examples of Controlled exposure (2):
Anaplasma marginale inoculation of young cattle (<6mo)
Canine Herpesvirus- horizontal exposure of young bitches before becoming pregnant
Pre-exposure prophylaxis:
Medicating an individual before exposure to a pathogen may protect the individual and the population
Physiologic response to short-term stress:
Induces catecholamine & glucocorticoid response
Physiologic response to long-term stress (or repetitive short term)
Continued corticosteroid response, disrupts homeostasis
Disrupts energy balance
decreases resistance to pathogens
causes recrudescence of latent pathogens
Causes hyperactive HPA response to future stressors
Aspects of the environment with effect on disease:
Stressors
Physical Injury
Cleanliness
Comfort
Goals of a preventative medicine plan
Prevent diseases
Detect and manage risks
Ensure optimal health outcomes
Key elements of prevention and control plans:
Management
Biosecurity
Monitoring/Surveillance
Management practices for prevention & control plans
Genetic selection
Preventatives
Vaccination
Nutrition
Repro Cycles
Environmental Management
Biosecurity:
A set of management and physical measures designed to reduce the risk of introduction, establishment and spread of animal diseases, infections or infestations to, from and within a population
Bioexclusion:
Prevention of disease introduction
Biocontainment:
Preventing the spread of disease within a farm or group of animals
Key Concepts of Bioexclusion:
Closed population
Quarantine
Pre-entry tests
Vector control
Managing movement patterns in facilities
Cleaning & Disinfection Procedures
PPE
Quarantine:
Separation of animals NOT KNOWN TO BE SICK for a period of time to allow for monitoring/testing for disease
3 levels of biosecurity:
Conceptual
Structural
Procedural
Biosecurity Hierarchy of Controls:
Elimination
Engineering Controls
Administrative Controls
PPE
Monitoring:
Systematic measurement, collation, analysis, and interpretation of animal health and welfare data of defined populations
Used to monitor health/disease patterns over time, inform management decisions, evaluate effects of intervention and changes
Surveillance:
Monitoring but used to identify specific diseases of concern that will initiate pre-specified control activities
Used for novel diseases, or diseases ided for control or eradication
Goals of primary infectious disease control strategies:
Prevent new cases
Interrupt transmission of pathogens to susceptible hosts or increase host resistance to infection-BEFORE infection occurs
Goals of secondary infectious disease control strategies:
Detect new cases early & intervene
Goals of teriary infectious disease control strategies:
Medical tx to prevent the worst outcomes of a disease- dz mitigation
Ring vaccination:
vaccination of all susceptible animals in a delineated area surrounding the location where an outbreak has occurred
Isolation:
Separation of Ill animals from healthy ones
cleaning:
removal of foreign material from objects
Disinfection:
elimination of many or all pathogenic microorganisms on an inanimate objects
Euthanasia:
Transitioning an animal to death as painlessly and stress free as possible (sometimes a tertiary strategy)
Mass Depopulation:
a method by which large numbers of animals must be destroyed quickly and efficiently with as much consideration given to the welfare of animals as practicable, given the extenuating circumstances
Preferred methods of carcass & waste disposal
Composting
Landfill
