Livestock Vaccine Flashcards
T/F: vaccines prevent infection
False- they stimulate the immune response to get protection from disease
What are the goals of livestock vaccination
1) Improve animal health and welfare
2) Increase animal productivity
3) Reduce consumer risk
4) Disease eradication
T/F: 100% vaccine efficacy in 100% of animals is possible
False
-instead aims to increase the level of herd immunity
can achieve 70-80% response in the herd
the level of immunity in a population required to prevent an outbreak
herd immunity
How might herd immunity be achieved to make disease spread less likely
Vaccination
Prior illness
What is the immune response to vaccination goals in herd
Memory cells produce antibodies (B cells) and memory cells that will be actived to lyse target cells (T cells)
The initial antibody response that occurs ~4 days post vaccination produces
IgM
The second antibody response that occurs ~10-14 days post-vaccination produces
IgG
The cell mediated response occurs about ______ days post vaccination
10-14 days
The booster vaccination produces
secondary or anamnestic response
-Predominantly IgG
-Stronger Ab, longer duration
the primary vaccine response is
largely IgM and some IgG, shorter duration
response of Ab and T cell
What kind of vaccines are bacterin
killed, inactivated
formed exotoxins that are denatured (often with formulin)
must contain adjuvant
Toxoid vaccine
T/F: toxoid vaccines are immunogenic
True
-Stimulates antibody production
-Antibodies then bind to and nautralize the toxin
Toxoid vaccines must contain
adjuvant
How have we traditionally assessed vaccine efficacy
Serologic data
the level of immunity in a population required to prevent an outbreak
herd immunity
Killed vaccines require
adjuvant
result in more injection reactions and boosters
T/F: with killed/ inactivated vaccines, there is a risk of reversion to pathogenic wild type
False
Killed vaccines produce strong _________ but less robust _____
strong humoral
less robust cell mediated
Killed vaccines are safer in what patients
pregnant and young patients
What are the disadvantages of killed vaccines
-Require booster vaccination
-Slower onset of protection
-Hypersensitivities can be seen
-Narrower spectrum of protection
What are the advantages of killed vaccines
-Induce IgA, IgG production
-Stimulate memory T cell production
-Safe in pregnant and young patients
-Cannot revert to wild type
-Thermostable
Induce mild infection with live organisms from non-target hosts or attenuated to reduce virulence
Modified live vaccines
How are modified live vaccines produced
reduction in viruence or attenuation via passage through cell lines, chicken embryos, selection of less virulent mutation
What is a major advantage of modified live vaccines
Fewer doses required
No adjuvant required
Multiple route of administration possible
longer lasting immunity
Do not need adjuvant
T/F: modified live dont need adjuvant
True
What are disadvantages to modified live vaccines
1) Sensitive to improper handling/storage - not thermostable
2) May cause disease in stressed or immunocompromised
3) Risk of reversion to virulence- can infect others in herd
4) Immunosuppressive
5) Risk of abortion, fetal infections- teratogenic effects
Is duration of immunity better with killed or MLV
MLV
Is cell mediated immunity better with killed or MLV
MLV
Are injection site reactions more common with killed or MLV
Killed
Is immunosuppression more common with killed or MLV
MLV
What are the requirements for vaccine licensing
1) Purity- product free of extraneous microorganisms/materials
2) Safety- freedom from from properties causing undue local or systemic reactions when the vaccine is used as labeled
3) Potency: relative strength of the product as determined by test methods approved by CVB
4) Efficacy: Ability or capacity of the product to affect the result for which it is offered when the product is used as labeled
What is true of efficacy trials for vaccines
vary greatly between products and manufacturers
can be exceptionally difficult to interpret and essentially impossible to compare
USDA thats that the manufacturer of a vaccine needs to dmeonstrate that it is
Safe
Pure
Reasonable expectation of efficacy
the period between the administration of vaccine and the time the animal or its products can legally enter the human food chain
Withdrawal time
what is the common slaughter withdrawal time for vaccines
21 days
-check specific product label
Withdrawal times are set for MLV to allow _____ and killed to allow ______
MLV: to allow so the live vaccine strain isnt found in products/ tissues
Killed: no infectious risk but to allow the adjuvants to clear from the tissues
What should you always do before giving a new vaccine
check the label
-specifics on type, precautions, indications, use
What must be done to do extra-label vaccine use in livestock
-Must provide extendend withdrawal times based on data (FARAD)
-Must use vet products when available
Most vaccines for small ruminants are
killed bacterin products
-requine timely booster, avoid maternal antibody interferences
Why should you administer vaccines in sheeps and goats SQ if possible
meat quality assurance
Do goats or sheep show more severe vaccine reactions
Goats
-Local swelling
-Anaphylaxis
With vaccination in sheep and goats there is a lack of
field based vaccine trials comparing efficacy between them
What are the risk factors for the Clostridium perfringens C &D + Tetanus vaccination in sheep and goats
1) High grain diet- Cl. perfringens type D
2) Processing- castration, tail docking (Tetanus)
3) Wounds (Tetanus)