21. vaccines

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21. vaccines

  1. 1. Chapter 21 Vaccines Copyright © 2011 Delmar, Cengage Learning
  2. 2. Immunity <ul><li>Nonspecific immunity </li></ul><ul><ul><li>Includes things such as physical barriers, mucus production, inflammation, fever, and phagocytosis </li></ul></ul><ul><ul><li>Directed against all pathogens; is the initial defense against invading agents </li></ul></ul><ul><li>Specific immunity </li></ul><ul><ul><li>Takes over when the nonspecific mechanisms fail </li></ul></ul><ul><ul><li>Targeted for a specific antigen; has memory </li></ul></ul><ul><ul><li>Arises from B- and T-lymphocytes </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  3. 3. Types of Immunity <ul><li>Cell-mediated immunity </li></ul><ul><ul><li>T-lymphocytes directly attack the invading antigen </li></ul></ul><ul><ul><li>Important for protecting against intracellular bacterial or viral infections, fungal diseases, and protozoal diseases </li></ul></ul><ul><li>Antibody-mediated immunity </li></ul><ul><ul><li>B-lymphocytes produce antibodies that react to antigen </li></ul></ul><ul><ul><li>Important for extracellular phases of systemic viral and bacterial infections and protection against endotoxin and exotoxin-induced disease </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  4. 4. Ways to Acquire Specific Immunity <ul><li>Active immunity </li></ul><ul><ul><li>Arises when an animal receives an antigen that activates B- and T-lymphocytes </li></ul></ul><ul><ul><li>Creates memory </li></ul></ul><ul><li>Passive immunity </li></ul><ul><ul><li>Arises when an animal receives antibodies from another animal </li></ul></ul><ul><ul><li>Provides immediate onset of immunity, but the animal is protected for a shorter time (no memory) </li></ul></ul><ul><li>Natural immunity </li></ul><ul><ul><li>Acquired during normal biological experiences </li></ul></ul><ul><li>Artificial immunity </li></ul><ul><ul><li>Acquired through medical procedures </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  5. 5. Vaccines <ul><li>A vaccine is a suspension of weakened, live, or killed microorganisms administered to prevent, improve, or treat an infectious disease </li></ul><ul><li>Types of vaccines: </li></ul><ul><ul><li>Inactivated (killed): made from microbes, microbe parts, or microbe by-products that have been chemically treated or heated to kill the microbe </li></ul></ul><ul><ul><ul><li>Contain adjuvants (substances that enhance the immune response by increasing the stability of the vaccine in the body); may cause vaccine reactions </li></ul></ul></ul><ul><ul><ul><li>Advantages: safe; stable; unlikely to cause disease </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: need repeated doses; possible reactions </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  6. 6. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Attenuated (modified-live): microorganisms go through a process of losing their virulence (called attenuation ), but must be able to replicate within the patient to provide immunity </li></ul></ul><ul><ul><ul><li>Advantages: immunity lasts longer; has better efficacy and quicker stimulation of cell-mediated immunity than killed vaccines </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: possible abortion; can produce mild forms of the disease; can shed into the environment; proper handling/storage is critical </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  7. 7. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Live: made from live microorganisms that may be fully virulent </li></ul></ul><ul><ul><ul><li>Advantages: fewer doses needed; last longer; inexpensive; adjuvants not needed </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: residual virulence that requires carefully handling </li></ul></ul></ul><ul><ul><li>Recombinant: a gene or part of a microorganism is removed from one organism (usually the pathogen) and inserted into another microorganism </li></ul></ul><ul><ul><ul><li>Advantages: fewer side effects; effective immunity; varied routes of administration </li></ul></ul></ul><ul><ul><ul><li>Disadvantage: increased cost </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  8. 8. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Adjuvants: substances that enhance the immune response </li></ul></ul><ul><ul><li>There are four types of adjuvants: </li></ul></ul><ul><ul><ul><li>Depot </li></ul></ul></ul><ul><ul><ul><li>Particulate </li></ul></ul></ul><ul><ul><ul><li>Immunostimulatory </li></ul></ul></ul><ul><ul><ul><li>Mixed </li></ul></ul></ul><ul><ul><li>Depot adjuvants protect antigens from rapid degradation which contributes to a prolonged immune response </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  9. 9. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Particulate adjuvants deliver antigen in such a way that both cell-mediated and humoral immunity are enhanced by stimulation of antigen processing </li></ul></ul><ul><ul><li>Immunostimulatory adjuvants promote cytokine production </li></ul></ul><ul><ul><li>Mixed adjuvants combine a particulate or depot adjuvant with an immunostimulatory agent </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  10. 10. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Polyneucleotides: or DNA vaccines injects DNA that encodes for foreign antigens is another type of vaccine </li></ul></ul><ul><ul><ul><li>Advantage: that it is possible to select only the genes for the antigen of interest </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  11. 11. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Toxoids: “vaccine” used against a toxin that has been deactivated by heat or chemicals, but is still able to stimulate antibody production </li></ul></ul><ul><ul><ul><li>Advantage: provides protection against toxin </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: shorter duration of effectiveness; may contain adjuvants </li></ul></ul></ul><ul><ul><li>Antitoxins: substances that contain antibodies obtained from an animal that has been hypersensitized to neutralize toxins </li></ul></ul><ul><ul><ul><li>Advantage: quick protection against a toxin </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: short-lived protection; may contain preservatives that can cause reactions </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  12. 12. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Antiserum: antibody-rich serum obtained from a hypersensitized or actually infected animal </li></ul></ul><ul><ul><ul><li>Advantage: provides quick protection against a microorganism </li></ul></ul></ul><ul><ul><ul><li>Disadvantages: shorter duration of effectiveness; may contain adjuvants </li></ul></ul></ul><ul><ul><li>Autogenous: vaccine produced for a specific disease in a specific area from a sick animal </li></ul></ul><ul><ul><ul><li>Advantage: provides protection against the specific organism in a specific area </li></ul></ul></ul><ul><ul><ul><li>Disadvantage: may contain endotoxin and other by-products found in the culture </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  13. 13. Vaccines <ul><li>Types of vaccines (cont.): </li></ul><ul><ul><li>Multiple-antigen vaccines are called polyvalent </li></ul></ul><ul><ul><li>Polyvalent vaccines contain more than one antigen </li></ul></ul><ul><ul><ul><li>Contain a mixture of different antigens and are more convenient to administer because fewer injections are needed </li></ul></ul></ul><ul><ul><ul><li>Adverse reaction increases as the number of antigens increases </li></ul></ul></ul><ul><ul><li>To be approved, must show that each part of the polyvalent vaccine induces the same level of immunity as does the single-antigen vaccine </li></ul></ul><ul><ul><li>Monovalent vaccines are vaccines with only a single antigen present </li></ul></ul><ul><ul><ul><li>Using several monovalent vaccines may expose the animal to higher levels of adjuvants </li></ul></ul></ul><ul><ul><ul><li>Must give more injections </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  14. 14. Maternally Derived Antibodies <ul><li>Maternally derived antibodies are antibodies that offspring receive passively from their mothers, either from colostrum or via the placenta </li></ul><ul><li>Maternally derived antibodies give the offspring disease resistance for a few days and provide variable antibody levels for up to nine weeks </li></ul><ul><li>To enhance this protection, young animals receive vaccinations and booster vaccinations to ensure appropriate immunity </li></ul><ul><ul><li>Booster vaccines are needed because effective vaccination varies among individuals, because of variable levels of maternal antibodies </li></ul></ul><ul><ul><li>Booster vaccines also allow antibody levels to rise to satisfactory levels </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  15. 15. Vaccine Reactions <ul><li>Although vaccines are considered safe, vaccine reactions can occur </li></ul><ul><li>All vaccine reactions must be recorded in the medical record </li></ul><ul><li>Typical vaccine reactions: </li></ul><ul><ul><li>Location reactions at the injection site </li></ul></ul><ul><ul><li>Fever </li></ul></ul><ul><ul><li>Lethargy </li></ul></ul><ul><ul><li>Vomiting </li></ul></ul><ul><ul><li>Salivation </li></ul></ul><ul><ul><li>Difficulty breathing </li></ul></ul><ul><ul><li>Vaccine-associated sarcomas in cats </li></ul></ul><ul><ul><li>Autoimmune hemolytic anemia in dogs </li></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  16. 16. Issues in Vaccine Use <ul><li>Consider the following with all vaccine protocols: </li></ul><ul><ul><li>Vaccine issues </li></ul></ul><ul><ul><ul><li>Proper care and handling </li></ul></ul></ul><ul><ul><ul><li>Proper route of administration </li></ul></ul></ul><ul><ul><ul><li>Proper use (do not mix vaccine products) </li></ul></ul></ul><ul><ul><ul><li>Proper dose </li></ul></ul></ul><ul><ul><li>Patient issues </li></ul></ul><ul><ul><ul><li>Animal age </li></ul></ul></ul><ul><ul><ul><li>Freedom from disease </li></ul></ul></ul><ul><ul><ul><li>Concurrent use of medication </li></ul></ul></ul><ul><ul><ul><li>Pregnancy </li></ul></ul></ul><ul><ul><ul><li>Environment </li></ul></ul></ul>Copyright © 2011 Delmar, Cengage Learning
  17. 17. Vaccine Protocols <ul><li>Practice of annual vaccination is now under debate </li></ul><ul><li>One way to discover when revaccination is necessary is via the antibody titer </li></ul><ul><ul><li>An antibody titer is a serum test that reveals the level of antibody to a particular antigen in a particular individual </li></ul></ul><ul><ul><li>Antibody titers are expressed as 1:2, 1:4, etc., a ratio that represents the dilution at which the immune response is still adequate </li></ul></ul><ul><li>Core vaccines are recommended for all individual animals </li></ul><ul><li>Noncore vaccines are recommended only for individual animals deemed to be at high risk for contact with the organism </li></ul>Copyright © 2011 Delmar, Cengage Learning
  18. 18. Species-Specific Vaccine Protocols <ul><li>Examples of vaccines available for a variety of species are listed in the textbook </li></ul>Copyright © 2011 Delmar, Cengage Learning

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