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IBD_Vaccination

"عسى أن تكون علما ينتفع به"
Poultry Gumboro
Infectious bursa disease
IBDV
Vaccines IBD

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IBD_Vaccination

  1. 1. IBD Vaccination
  2. 2. Plan of talk  Hyperimmunisation of breeders  Vaccination and maternal immunity  Types of vaccines  Live vaccines  Choosing live vaccine  Timing of vaccination  Characteristics of good life vaccine
  3. 3. Plan of talk  Hyperimmunisation of breeders  Vaccination and maternal immunity  Types of vaccines  Live vaccines  Choosing live vaccine  Timing of vaccination  Characteristics of good life vaccine
  4. 4. To protect young chick during the first one to two critical weeks post hatch. Parent Breeder Chickens Are Hyperimmunised Against IBDV.
  5. 5. Live IBD Vaccine (2) 4 - 10 weeks of age Inactivated IBD vaccine (1) 16 - 18 weeks of age or before onset of production
  6. 6. The resultant high level of IBDV neutralizing antibodies are passively transferred to the day old chick via the yolk sac (MDA).
  7. 7. Plan of talk  Hyperimmunisation of breeders  Vaccination and maternal immunity  Types of vaccines  Live vaccines  Choosing live vaccine  Timing of vaccination  Characteristics of good life vaccine
  8. 8. IBD Vaccine and MDA  Since IBDV enters through the oral route, and should find its way to the bursa via the blood stream, any MDA in chick blood would neutralize the vaccine.
  9. 9. MDA Maternal Derived Antibodies
  10. 10. MDA Decrease  MDA is protective when present at a sufficiently high titre.  Due to metabolism and growth, the antibody titre declines to half (t1/2) at a rate of: • Broilers 3.5 days • Broiler breeders 4.5 days • Layers 5.5 days  2 to 3 weeks post hatch, the susceptibility of a chicken flock to an IBDV infection increases.
  11. 11. MDA & Vaccination Breeder flocks are immunized against IBD, so they would confer protective antibodies to their progenies. Advantage  Protects chickens from early infection. Disadvantage:  Neutralizes live vaccines.
  12. 12. MDA Decrease ELISA titer Age  Maternal antibody will normally protect chicks for 1-3 weeks  By boosting the immunity in breeder flocks with oil adjuvanted vaccines, passive immunity may be extended to 4 or 5 weeks
  13. 13. MDA Variation ELISA titer Age Standard broiler Layer Organic broiler
  14. 14. MDA Protective Threshold ELISA titer Age Protected Non protected Protective threshold against classical IBDV Protective threshold against vvIBDV
  15. 15. Cont. … ELISA titre Age Possible to use intermediate plus Possible to use intermediate Vaccine take intermediate Vaccine take intermediate plus
  16. 16. Plan of talk  Hyperimmunisation of Breeders  Vaccination and Maternal Immunity  Types of Vaccines  Live Vaccines  Choosing live vaccine  Timing of Vaccination  Characteristics of good life vaccine
  17. 17. Types of IBD vaccines 1. Life attenuated vaccines 2. HVT Recombinant Vaccine 3. Virus-Antibody Complex Vaccines 4. Inactivated vaccines
  18. 18. Live Attenuated Vaccines Live attenuated vaccines  They are administered as the primary defense in the young susceptible chicken.  Commercial live vaccines are classified into 3 groups: a) Intermediate strains b) Intermediate plus strains c) Hot strains
  19. 19. HVT Recombinant Vaccine Composition  The concept of recombinant vaccines is to insert genes of critical immunizing epitopes (VP2) of IBD virus into a vector virus HVT (herpesvirus of turkeys).  While the vector virus replicates, the VP2 also replicates at the same rate resulting immunization against both.
  20. 20. Cont. … Precautions  The HVT is usually a slow replicating virus, it induces immune response after 14 days.  Adding a gene to the HVT may slows its replication and extends the 14 days.
  21. 21. Immune Complex Vaccine Composition Antibody specific for the virus + Vaccine virus  Both are mixed in an appropriate ratio.  The antibodies surround the vaccine virus.
  22. 22. Cont. … Significance of adding antibodies  The presence of antibodies protect vaccine virus from being neutralized by MDA.  Antibodies delay, by several days, the normal course of vaccine virus replication.  This process controls the time of releasing vaccine virus.
  23. 23. Cont. … Precaution  The level of MDA should be adjusted to the vaccine virus strain.
  24. 24. Inactivated vaccines  They are administered to boost the immunity of parent birds.  Not used for layers
  25. 25. Plan of talk  Hyperimmunisation of Breeders  Vaccination and Maternal Immunity  Types of Vaccines  Live Vaccines  Choosing live vaccine  Timing of Vaccination  Characteristics of good life vaccine
  26. 26. Live Vaccines Objective of using life vaccines: Live vaccines are administered to achieve active immunity.
  27. 27. Classification of Live Vaccines Live vaccines are classified into 3 groups according to their ability to break through levels of MDA. 1. Mild  These vaccine strains are highly attenuated.  They can break through very low levels of MDA.  They are no longer applicable in the commercial environment.
  28. 28. Cont. … 2. Intermediate  They are attenuated IBDV strains.  They can break through MDA titres ≤ 6 log2 VN 3. Intermediate Plus/Hot  They are less attenuated IBDV strains  They can break through MDA titres ≤ 8 log2 VN
  29. 29. When to Use More Invasive Vaccine?  The main feature of the presence of very virulent IBDV field challenge is increased mortality.  vvIBDV can break through higher levels of MDA than intermediate IBDV vaccines infections can occur before it is possible to immunise the chicks with intermediate vaccines.
  30. 30. Cont. …  To be able to compete with such vvIBDV viruses and induce immunity in the face of still high maternal immunity, more invasive IBDV vaccines strains are required.  The main objective is to reduce mortality and the prevalence of vvIBDV in the flocks  Once this aim has been reached return to intermediate vaccines
  31. 31. General Recommendations  In farms with IBD problems or in “hot areas” 1. Use a hot or intermediate plus vaccine 3 – 4 cycles; 2. Followed by an intermediate vaccine  In “endemic” areas, multiple age farms and farms relying solely on hot vaccines 1. Use continuously a hot vaccine. Whenever possible try to switch back from a hot vaccine to an intermediate
  32. 32. Plan of talk  Hyperimmunisation of Breeders  Vaccination and Maternal Immunity  Types of Vaccines  Live Vaccines  Choosing live vaccine  Timing of Vaccination  Characteristics of good life vaccine
  33. 33. Choosing Live Vaccine Choice of live vaccine depends on: 1. Virulence of field infection  Mild and Intermediate vaccine strains can not protect against vvIBDV.  Mild and Intermediate vaccine strains cannot be administered at an early age due to MDA interference. 2. Age of chickens to be vaccinated  The earlier the vaccination the higher the level of MDA, requiring a stronger vaccine.
  34. 34. Cont. … 3. Age at which Gumboro outbreak occurs.  Early outbreaks require earlier vaccination.  Infections before 2 weeks require using vaccine that cover variant strains.  Late infections requires intermediate plus or hot strains.
  35. 35. Plan of talk  Hyperimmunisation of Breeders  Vaccination and Maternal Immunity  Types of Vaccines  Live Vaccines  Choosing live vaccine  Timing of Vaccination  Characteristics of good life vaccine
  36. 36. Timing of Vaccination  Too soon  MDA neutralises vaccine  Late  Late protection  Optimal  Sooner the better 36
  37. 37. Cont. … There is no IBD vaccination schedule that can be routinely recommended.
  38. 38. Cont. … Factors influencing a vaccination schedule include: 1. Type of chicken to be vaccinated (broiler or commercial layer). 2. Level of MDA – The higher the start level of MDA the later the age of vaccination. 3. Uniformity of MDA – If the variation in MDA levels is too high (CV>30%) a second IBD live vaccination is required to effectively immunize the flock. 4. Field pressure.
  39. 39. Plan of talk  Hyperimmunisation of Breeders  Vaccination and Maternal Immunity  Types of Vaccines  Live Vaccines  Choosing live vaccine  Timing of Vaccination  Characteristics of good life vaccine
  40. 40. Characteristics of Good Life Vaccine 1. Early protection. 2. Minimum immunosuppression. 3. Highest antibody titer. 4. Cross protection between different strains. 5. Easy application.

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"عسى أن تكون علما ينتفع به" Poultry Gumboro Infectious bursa disease IBDV Vaccines IBD

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