title: Simultaneous detection of vaccinal and field infectious bursal disease viruses in layer chickens challenged with a very virulent strain after vaccination.
abstract: Infectious bursal disease virus is an important poultry pathogen. It is distributed worldwide and causes significant economic losses. In this study, a system was adopted for the simultaneous monitoring of vaccine and virulent strains using reverse transcription polymerase chain reaction (RT-PCR). After the decay of maternal antibodies, chickens were vaccinated at the age of 37 days with a virus of intermediate virulence and challenged at 5, 10 and 14 days post vaccination (dpv). The challenge was done with IBDV strain CH/99. Sequencing of the hypervariable region of VP2 has shown that CH/99 belongs to the very virulent group of viruses. The vaccine virus could be found in the bursa of Fabricius, spleen, thymus and bone marrow until 24 dpv. The CH/99 challenge virus was found in the bursa and lymphoid organs when chickens were challenged at 5 and 10 dpv. When challenge was performed at 14 dpv, the pathogenic virus could not be found in the bursa and other lymphoid organs.
authors.affiliation: Veterinary Institute Požarevac Požarevac Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Dobrosavljević
authors.affiliation: Veterinary Institute Kraljevo Kraljevo Serbia.
authors.forename: Dejan
authors.initials: D
authors.lastname: Vidanović
authors.affiliation: Scientific Veterinary Institute 'Novi Sad' Rumenački put 20 Novi Sad Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Velhner
authors.affiliation: Research Veterinary Institute of Serbia Belgrade Serbia.
authors.forename: Biljana
authors.initials: B
authors.lastname: Miljković
authors.affiliation: University of Novi Sad Faculty of Agriculture, Department for Veterinary Medicine Novi Sad Novi Sad Serbia.
authors.forename: Branislav
authors.initials: B
authors.lastname: Lako
keywords: Chicken; PCR; infectious bursal disease virus