Lecture 3a. Important viral disease in poultry - NDV.pdf

VIRAL INFECTIOUS DISEASES Lecture 3. Infectious Diseases in Poultry Dinh Xuan Phat, DVM, MSc, PhD  Outline 3. Lecture 3: important viral disease in poultry (agent, epidemiology, pathogenesis, spreading, symptom/lesion, morbidity/mortality, diagnosis, preventi...

VIRAL INFECTIOUS DISEASES Lecture 3. Infectious Diseases in Poultry Dinh Xuan Phat, DVM, MSc, PhD  Outline 3. Lecture 3: important viral disease in poultry (agent, epidemiology, pathogenesis, spreading, symptom/lesion, morbidity/mortality, diagnosis, prevention, treatment) a. ND b. Gumboro c. IB d. Marek e. Duck cholera f. Duck hepatitis  Newcastle Disease Exotic Newcastle Disease, Pseudo-Fowl Pest, Pseudovogel- Pest, Atypical Geflugelpest, Pseudo-Poultry Plague, Avian Pest, Avian Distemper, Ranikhet Disease, Tetelo Disease, Korean Fowl Plague, and Avian Pneumoencephalitis  Overview Organism Economic Impact Epidemiology Transmission Clinical Signs Diagnosis and Treatment Prevention and Control Actions to Take THE ORGANISM Newcastle Disease Virus Family Paramyxoviridae – Genus Avulavirus 9 serotypes – APMV-1 to APMV-9 Newcastle disease is APMV-1 Strains of NDV classified according to their pathogenicity into: 1. Viscerotropic /ˌvisərəˈtrōpik/ velogenic /velo-’jenik/ NDV (Doyle's form). 2. Neurotropic velogenic NDV (Beache's form). 3. Mesogenic /mez'ō-jen'ik/ NDV (Beaudett's form). 4. Lentogenic NDV (Hitchner form). 5. Asymptomatic enteric NDV. IMPORTANCE History 1926 – Java, Indonesia – Newcastle-upon-Tyne, England Probable earlier outbreaks in Central Europe 1896: Western Scotland, cause of death of all chickens? 4 panzootics from 1926 to 1981  Economic Impact Global economic impact – vND more costly than any other animal virus? Control measures expensive Repeated testing for trade purposes Developing countries – Endemic vND affects quality and quantity of dietary protein – Significant effect on human health EPIDEMIOLOGY Geographic Distribution Endemic – Asia, the Middle East, Africa, Central and South America Vaccine use makes assessment of true geographical distribution difficult International monitoring – FAO – OIE EPIDEMIOLOGY Endemic: a disease that exists permanently in a particular region or population. Malaria is a constant worry in parts of Africa. Enzootic: Endemic in animals. Epidemic: An outbreak of disease that attacks many peoples at about the same time and may spread through one or several communities. Pandemic: When an epidemic spreads throughout the world. Zoonotic: a disease that normally exists in animals but that can infect humans.  Morbidity/Mortality Morbidity: up to 100% Mortality: 90% Varies greatly depending on – Virulence and strain – Avian species and susceptibility of host – Environmental conditions – Vaccination history Some species show few or no signs – Carrier state may exist Center for Food Security and Public Health, Iowa State University, 2011 TRANSMISSION Animal Transmission Direct contact with feces, respiratory secretions Indirect contact – Feed, water – Equipment – Human clothing Contaminated or incompletely inactivated vaccines  Animal Transmission Survives for long periods in the environment Incubation period – 2 to 15 days – 5 to 6 days average Migratory birds, feral pigeons – Contamination of poultry feed  Human Transmission Mild conjunctivitis – Virus shed in ocular /ˈɒk.jə.lər/ secretions – Avoid contact with avian species Lab workers and vaccination crews most at risk No cases from handling or consuming poultry products No human-to-human spread DISEASE IN ANIMALS Incubation and Pathogenesis  It varies from (2 to 15) days in poultry depending on the virulence of the strain.  In chickens infected with velogenic isolates; (2 to 6) days.  In some avian species; 25 days. Pathogenesis /ˌpæθ.əˈdʒen.ə.sɪs/:  The virus replicates in the mucosa of the upper respiratory and intestinal tracts.  Virus spreads via blood to spleen and bone marrow (viremia) causing infection of other organs: lung ,intestines & C.N.S.  Clinical Signs Drop in egg production Numerous deaths within 24 to 48 hours Deaths continue for 7 to 10 days Surviving birds may have neurological or reproductive damage  Clinical Signs Edema of head, especially around eyes Greenish, dark watery diarrhea Respiratory and neurological signs Signs vary with species and virulence Center for Food Security and Public Health, Iowa State University, 2011 Twisting and circling of The bird displays Torticollis head and neck. /tɔː.tɪˈkɒl.ɪs/  Diarrhea with green bile Square appearance of the head pigment and white urates. due to bilateral facial edema.  Postmortem Lesions Edema of head, neck Edema, hemorrhage, necrosis or ulceration of lymphoid tissue Hemorrhagic lesions – Tracheal mucosa – Proventriculus – Intestinal mucosa  Postmortem Lesions Subconjunctival Odema and hemorrhages in haemorrhages with external the conjunctiva and lesions. infraorbital sinus.  Postmortem Lesions Accumulation of mucus in Mild haemorrhagic the respiratory tract. lesions in the mucosa of  Postmortem Lesions Congestion and haemorrhages in the Severe thymus atrophy pharynx and proximal with extensive trachea. haemorrhages.  Postmortem Lesions Inflammation with pinpoint heamorrhagic lesions in the proventriculus mucosa.  Postmortem Lesions Necrosis of lymphoid tissue at Extensive haemorrahges the caecal lymph node. and ulcers of caecal tonsils mucosa.  Postmortem Lesions Acute focal lymphoid Focal ulceration and necrosis in the duodenum. haemorrhage in the small intestine.  Postmortem Lesions Haemorrhagic lesions along Severe haemorrhages in the the entire length of the rectal mucosa. intestine.  Postmortem Lesions Ulcers with fibrin /ˈfɪb.rɪn/ Pulmonary congestion /ˈfaɪ.rɪn/ accumulation in the and edema. mucosa of the cloaca.  Postmortem Lesions The spleen is enlarged with Extensive haemorrhages numerous white lesions. on the liver.  Postmortem Lesions Odema and Severe acute haemorrahges haemorrahges in mucosa and congestion in the of fabricius /fəˈbriʃi-əs/ ovarian follicles.  Postmortem Lesions Severe acute haemorrhages and congestion.  Differential Diagnosis Highly pathogenic avian Mycoplasmosis influenza Infectious bronchitis Fowl cholera /ˈkɒ-lə-rə/ Management Laryngotracheitis problems Coryza – Water or feed deprivation Fowl pox (diphtheritic – Poor ventilation /dif-thi-ˈri-tik/ form)  Clinical Diagnosis Sudden decrease in egg production High morbidity and mortality Characteristic signs and gross lesions Center for Food Security and Public Health, Iowa State University, 2011  Laboratory Diagnosis Virus isolation RT-PCR Serology – No strain information – Cannot differentiate infected from vaccinated animals – May be used post-vaccination to confirm immune response Samples should only be sent under secure conditions and to authorized laboratories to prevent the spread of the disease  Diagnostic Samples: Samples from live birds:  Tracheal swabs.  Cloacal swabs.  Faecal swabs.  Serum. Samples from dead birds:  Lung, kidneys, intestine, spleen, brain, liver, and heart tissues. DISEASE IN HUMAN Clinical Signs in Humans Eye infections – Reddening, excessive tearing, edema of lids, conjunctivitis, subconjunctival hemorrhage – Usually transient, cornea not affected – Lab workers and vaccination crews most susceptible – No human-to-human spread Conjunctivitis in human. PREVENTION AND CONTROL Recommended Actions Confirmatory diagnosis Depopulation may be necessary Destruction – Exposed carcasses – Litter – Animal products Disinfection of premises Delay re-introduction of new birds for 30 days Control insects and mice, limit human traffic  Disinfection Household bleach, 6% Extremes in pH – Less than 2 or greater than 12 Heat – Boiling one minute Detergents Dryness Ultraviolet light and sunlight  Vaccination Vaccination routine worldwide Reduces clinical signs Does not prevent virus replication or shedding Not an alternative to good management, biosecurity, or good hygiene  Vaccination Program Type of Age Vaccine Administration Chicken NOBILIS® MA5 + Course spray or eye 1 day of age CLONE 30 drop application. Broilers Approx. 4 weeks Spray, or eye drop NOBILIS® CLONE 30 (if ND endemic) application. NOBILIS® MA5 + Course spray or eye 1 day of age CLONE 30 drop application Layers / Approx. 4 weeks Spray, or eye drop Breeders NOBILIS® CLONE 30 (if ND Endemic) application. NOBILIS® MA5 + Spray or eye drop Approx. 8 weeks CLONE 30 application At least 103 EID50 Infectious Bronchitis virus strain Ma5 (serotype Massachusetts) and 106 EID50 of the Newcastle Disease strain Clone 30. - In layer: revaccinate every 5-8 week in drinking water