An-Najah National University

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  • Saturday, August 22, 2009
  • Outbreak of Laryngotracheitis (LT) in vaccinated Commercial Layer Flocks in Palestine
  • Published at: The 2nd Scientific Conference of Animal Wealth Research

    This study was conducted during an outbreak of infectious laryngotracheitis ( ILT) in three flocks hyline breed of commercial   layers  with a total number of  20.000 housed in cage systems in Bal'a , East of Tulkarem , North Palestine .these flocks were previously vaccinated once at 15 weeks age with attenuated vaccine against ILT disease via cloacae . The clinical findings of the disease were : Respiratory distress including gasping , coughing , gargling , marked dyspnea  and  expectorating of vigorously blood stained mucous and some layers showed existence of dried blood around the nostrils and lower beaks ,  unilateral or bilateral closed eyes , lacrimation and the egg production decreased 30% . The morbidity rate was high and the mortality rate reached 12% . The necropsy findings of dead birds showed mucoid tracheitis , laryngitis , sever hemorrhages  in the trachea and the lumens were filled with mucus mixed with blood obstructing the trachea or  larynx , exudates , caseous material and existence of blood casts  along the entire length of the larynx and trachea . The disease was diagnosed by isolation of the ILT virus  from the dead and sick birds tracheal suspension by culturing  onto the chorioallantoic membrane (CAM ) of 10-12 day- old embryonated chicken eggs and identified by   neutralization test using reference anti-ILT serum and quantitative detection of antibodies level in layers sera   using ELT-LT ELISA KIT – Jordan –Bioindustris Center ( JOVAC ) . Histopathological study  revealed characteristic intranuclear  inclusion bodies in both experimentally infected cocks and tracheal section  of sick layers .


    Keywords : Iinfectious Laryngotracheitis ( ILT)  , Chorioallantoic membrane  (CAM) , Enzyme-Linked Immunosorbent Assay ( ELISA ) , Histopathology .

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Salameh Shehdeh Barhoom
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