11/7/14 Outline The Role of Vaccina2on and Lab Monitoring in the Control of Poultry Diseases Rocio Crespo •  Avian health and immune system •  Basics of Vaccina2on in Poultry –  Types of vaccines –  Vaccine delivery –  Vaccine failure •  Lab Monitoring –  Tasks –  Serologic tests and interpreta2on Disease development depends… Speciﬁc Immune System e siv Pas unity m Im •  Primary Organs •  Bird’s condi2on –  Yolk sac: Maternal immunity –  Bone Marrow: Precursor blood cells –  Thymus gland: T-‐cells (cell mediated immunity) –  Bursa of Fabricius: B-‐cells (humoral/an2bodies) –  Health or state of wellbeing –  Level of protec2on/immunity •  Invading pathogen/organism –  Number –  Virulence or strength Defense System Against Infec2ons •  Peripheral lymphoid 2ssue Disease agents: •  •  •  •  •  Deﬁciencies Toxins Viruses Bacteria Parasites Resistance: •  Good feed •  Intes2nal ﬂora •  Immunity –  Local –  Systemic Vaccina2on –  Harderian gland –  Cecal tonsils –  Spleen –  GALT A Im c2v mu e nit y Basics of Vaccina2on in Poultry Elements of a Vaccina2on Program •  To trigger immune system so to produce an2bodies èﬁght invading casual organisms •  Vaccina2on is a way of obtaining a control result with a minimum of harm to the birds Age of the First Vaccination –  A natural invasion caused infec2on will be uncontrolled and has the possibility of causing severe damage Interval between Subsequent Vaccinations Number of Vaccinations GOOD VACCINATION PROGRAM DESIGN Type of Vaccines Route of Vaccination 1. Stimulation & Maintenance of Protective Immunity 2. Development of Immunologic Memory 1 11/7/14 Basics of Vaccina2on in Poultry Requirements for Good Immune Response Basics of Vaccina2on in Poultry Types of vaccines •  Live and live-‐a[enuated-‐ either low dose or mild forms of disease organism Correct Vaccine Correct Vaccine Storage Good Nutrition GOOD IMMUNE RESPONSE No Immune Suppression Good Administration Technique Healthy Birds Correct Vaccination Program Basics of Vaccina2on in Poultry Live vaccines Disadvantages •  Vaccine agent is present in –  Humoral + cell-‐mediated poultry popula2on –  Diﬀerent classes of an2bodies •  Possibility of shedding of Rapid onset of vaccinal the vaccine agent protec2on •  Post vaccinal reac2ons are Easy mass applica2on possible No adjuvants needed No hypersensi2vity reac2ons Produc2on in big quan22es Advantages •  Create complex immunity •  •  •  •  vaccines due to their inability to infect and mul2ply in the host. Use adjuvant to compensate –  Killed (whole unit)-‐ high dose of dead pathogen –  Sub-‐unit-‐ puriﬁed an2gens extracted from the disease organism –  Conjugate-‐ contain the an2gen bound to a compound to form a complex that is detectable by the immune system –  DNA-‐ puriﬁed DNA for the an2gens that s2mulate an immune response to a disease organism No Stress •  •  Inac2vated-‐ Result may be weaker and shorter immunity than live Basics of Vaccina2on in Poultry Vector vaccines •  Recombinant-‐ Incorporates DNA of the pathogen into another organism that will be delivered as a live vaccine Basics of Vaccina2on in Poultry Inac2vated vaccines Advantages •  No introduc2on of a “new living agent” •  No shedding of the vaccine agent •  No post vaccinal reac2ons •  Accurate individual vaccina2on Disadvantages •  Reac2ons of hypersensi2vity possible •  Slow onset of protec2on •  Humoral immunity only •  High labor costs for applica2on •  Expensive produc2on of high quality vaccines Basics of Vaccina2on in Poultry Individual delivery of vaccine Advantages Disadvantages •  Ocular •  Bi-‐ or mul2valent an2gens •  No shedding of the vectored agent •  Accurate individual vaccina2on •  In ovo vaccina2on is possible •  Long-‐lived immune response •  Poten2al to diﬀeren2ate between infected and vaccinated (DIVA). •  High labor costs for applica2on, if parenteral •  Eﬀec2ve for systemic pathogens compared to respiratory/non-‐systemic •  Slow onset of protec2on •  Previous exposure to carrier may compromise immunity of the vectored agent •  Expensive produc2on •  Possibility of crea2ng new pathogens •  Injec2on: wing web, subcutaneous, intramuscular –  Vaccine makes its way into the respiratory tract via the lacrimal duct –  Use only speciﬁc diluent –  Use only sterile equipment –  Into the wing by a special needle(s) –  Use speciﬁc diluent for live vaccines 2 11/7/14 Basics of Vaccina2on in Poultry Mass applica2on •  Drinking water –  All equipment used for vaccina2on is carefully cleaned and free of detergents and disinfectants –  Only cold, clean water of drinking quality is used –  Ensure that all birds drink during the vaccina2on phase •  Spray –  Delivered onto the chickens (or into the air above the chickens) Basics of Vaccina2on in Poultry Reasons for Vaccine Failure •  Administra2on of a sub-‐op2mal dose of vaccine –  Poor vaccine quality (rare) –  Improper handling of the vaccine during transport and storage –  Errors in the vaccina2on technique •  Immune suppression –  Immune suppressive viral infec2ons –  Stress –  Mycotoxins •  High levels of maternal an2bodies •  Strong ﬁeld challenge Laboratory monitoring Lab Tasks •  Organize disease control program •  Early warning systems Correc2ve ac2on can be taken before disease / produc2on losses •  Measure vaccine performance •  Diagnos2c services •  Research on infec2ons Basics of Vaccina2on in Poultry Vaccine Monitoring •  Ascertain whether the vaccine has work or “taken” •  Many cases birds react approximately 5-‐7 days post-‐vaccina2on by showing signs of illness – slight cough, lethargy •  Blood samples may be taken and sent to the lab for serology assays (detec2on of an2bodies) Basics of Vaccina2on in Poultry Reasons for Vaccine Failure •  The causa2ve agent is not covered by the used vaccine (e.g. IBV variants, AIV subtypes) •  Vaccina2on is too late –  Birds are already infected at 2me of vaccina2on –  Field infec2on occurs before development of vaccinal immunity •  Weaning of vaccinal immunity aher 2me Serologic Monitoring Tests Agglu2na2on test –  Simplest and least expensive –  Mul2ple avian species –  Qualita2ve (Pos / Neg) –  False reac2on è use as screening tool –  Examples: •  Salmonella Pullorum/Gallinarum •  Mycoplasma gallisep0cum (MG) and M. synoviae (MS) 3 11/7/14 Serologic Monitoring Tests Agar gel immune diﬀusion (AGID) –  Semi-‐quan2ta2ve –  Diﬃcult to interpret (especially weak posi2ves) –  Cannot be automated –  Example: •  Avian inﬂuenza Serologic Monitoring Tests Enzyme-‐linked immunosorbent assay (ELISA) –  Preferred method for commercial poultry –  Quan2ta2ve and easily automated –  False reac2on è may need conﬁrma2on –  Species speciﬁc Serologic Monitoring Tests Hemagglu2na2on inhibi2on (HI) –  Gold standard for serologic assays –  Quan2ta2ve assay –  Highly speciﬁc –  Examples: •  Avian inﬂuenza subtypes •  Infec2ous bronchi2s serotype •  Conﬁrma2on MG and MS •  Newcastle disease ELISA interpreta2on •  Mean Titer -‐ Intensity of response –  Baseline 2ters •  %CV -‐ Uniformity of response –  Excellent: <30% –  Good: 30-‐50% –  Needs improvement: >50% •  Mean Titer Over Time -‐ Persistence of response ✗  Poor vaccination / titers ü Good vaccination / titers 4 11/7/14 Example for organized monitoring program in layers Serologic Tests Age Day 1 Sample - Transfer box paper Test -  Salmonella -  Serum -  MG 10 days -  Droppings -  Salmonella – IBD – AI Marketing Age -  Serum -  ND box paper -  Salmonella. -  MG Week 9 - Serum - ND Week 16 -  Droppings - Salmonella -  Serum - MG -  Droppings - Salmonella – IBD - AI – IBV - etc –ND – AI -etc -  Serum - ND – AI – MG -etc Week 45 - Serum - MG –ND – AI -etc Week 62 -  Droppings - Salmonella -  Serum - MG Example for organized monitoring program in broilers Age - Transfer Test -  Serum Week 22 Day 1 Sample –ND- AI -etc Summary •  •  •  •  Avian immune system Role of vaccina2on Types of vaccines and delivery Vaccine monitoring – IBV – AI – IBD 5