病毒性疾病.pdf
Most important viral diseases and its control in poultry Andre Derkx DVM Introduction Andre Derkx Married 3 Children GPS operation in Netherlands Pure Lines Netherlands Governments/European Union Export contracts Client support Subjects What is a virus and what are the most important ones for poultry The immune system of the chickens and the response to a viral challenge The control of viral challenges by bio-security The control of viral challenges by vaccination What is a virus ? Size 400 Nm Needs living host cell Forces the cell to copy viral genes Forces the cell to read viral genes and with that produce viral proteins Cell type specific Different virusses / different cells Cell death or unlimited multiplication The structure Attaching and multiplication http:/ The most important viruses for poultry horizontal spread Marek A.I. ND IBD IBV ILT FP TRT horizontal +vertical spread ALV AE CAV Adeno group Reo Image herpes virus Response: immune system Passive immune system antibodies from Mamma (not Pappa !) Active immune system Local General defence cells Systemic T cells, lymfocytes (spleen, cecal tonsils, harden gland) B cells, antibodies (bursa) Native (immune response to certain antigens already present-evolution) Product System Cellular Antibodies Passive + Active Native + + Local + + Systemic + + Immune system local systemic Early in life Fast Local Low influence mat. ab Short lasting Repeat Not all diseases Not complete at hatch Slow Through the entire body Influence mat.ab Memory Very functional Expensive in energy Not all viruses give the same immune response Mat AB Cellular B cell AB Mat AB Cellular B cell AB Marek n y n ALV ? y Y AI y y y AE y y n ND y y y CAV y y y IBV y y y Adeno Y y y IBD y n y ILT ? y n TRT ? y y REO y ? y The role of bio security in viral challenges Big differences in what you can expect Viral versus bacterial Viruses do not have natural enemies, bacteria do! Horizontal versus vertical Viral structure, read sensitivity to disinfectants Surviving in carriers (dust/insects/humans etc) Bio inclusion possible Bacteriophage killing a bacteria The role of bio security in viral challenges Example Marek Strict horizontal Shedding cannot be blocked by vaccination, only limited Reasonable sensitive for disinfectants Shedding mainly by air as dust from feather follicles Carriers as people/insects not very important The role of bio security in viral challenges Example IBD Strict horizontal Shedding can be fully blocked by proper vaccination Good sensitivity for disinfectants Shedding mainly by feces. Carriers as people/insects/trucks are the most important disease spreaders Vaccine response: broilers versus breeders Broilers Fast action Short lasting Block disease Cheap $ FCR Block horizontal shedding (IBD) Breeders Fast for some vaccines Long lasting Block disease Block horizontal shedding Block vertical shedding Offspring effect Vaccinations as part of your biosecurity Broilers Live vacccines Spray Eyedrop Injections In ovo At hatch Drinking water Killed vaccines Injections Recombinants Injection In ovo At hatch Breeders Live vacccines Spray Eyedrop Injections In ovo At hatch In rearing Drinking water Killed vaccines Injections Eye drop Recombinants Injection In ovo At hatch Recombinants challenge HVT-ND 2 companies HVT-IBD 2 companies HVT-ILT FP-AI FP-ILT FP-MG Breeders and challenges In general fine. Critical: IBV and A.I. variants Combination of vaccines (viral as bacterins) Feed allocation when multiple injections MG vaccinations interfering with PCR testing IBV vaccinations in breeders Use variants and classic strains First 14 days, a variant + a classic live vaccination Repeat the live vaccines, each type, if possible 1 x before oil injection Broilers and challenges Respiratory complex After 25 days Multi age farming Recombinant ND vaccine removes a factor (la sota). Calculate late protection. Need a first day life ND vaccine. Enteritis Maldigestion-malabsorption Astro-adeno viruses Genetics Certain parts of the base pair sequence are critical for the 3 D structure. Epitope, special group of codons responsible for the 3 D structure New diagnostic tool New vaccines will be based on this knowledge In the past by protector type In future by epitope type More specific Custom made Maintain vaccine Gizzard and proventriculus erosions Vaccines coming up ? BLS, hepatitis E Vaccine coming up? General rules 1 Interspace in between competitive vaccines 10 days Mixing vaccines with same receptor, look at least into viral dose per chicken Do not mix 2 HVT recombinants Use a red dye for hatchery spray vaccinations Use a green/blue dye for Marek, Reo live, eyedrops, drinking water vaccinations General rules 2 Rearing first live then killed vaccine. Priming ! Combine injections as much as possible Extra feed allocation after injections with combi-vaccines, uniformity! The message Investigate your challenges and use new techniques Not all viruses are equal Bio-security versus vaccination strategy Hatchery applications are more reliable and more secure Broilers: ND-AI-IBV-IBD focus Make space between respiratory vaccinations A lot of new things coming up Thank you for your attention Questions
