A B S T R A C TEgypt is endemic for Newcastle disease virus (NDV) with continuous long-lasting outbreaks causing significant losses in the poultry industry. This study was designed to isolate and identify NDV from different localities in Egypt (Giza, Gharbiya, Kalyobiya, Sharkia, Menofia, Fayoum and Minia) among chicken flocks and estimate its virulence using Mean death time (MDT) and intra-cerebral pathogenicity index (ICPI). Forty samples were collected from chickens either alive or dead showing clinical findings and post-mortem lesions characteristic for NDV. Virus propagation in embryonated chicken eggs was confirmed by hemagglutination (HA) test and identified by hemagglutination inhibition (HI) test using NDV specific antiserum. The results indicated that 23 (57.5 %) out of 40 samples were NDV positive. The isolate from Giza was velogenic with MDT of 48 hours and ICPI of 1.625. While the isolate from Qualubiya was lentogenic with MDT of 96 hours and ICPI of 0.4375.These findings provide data on biological pathotyping of NDV in chickens in Egypt and emphasize importance of NDV surveillance for improving of strategies for the control of the disease.

A B S T R A C TInfectious bursal disease virus (IBDV) remerged frequently in Qualubyia was the cause of serious economic losses. Twenty field samples were collected from broiler chick farms in different localities of the governorate in January 2015, subjected for isolation on specific pathogen free-embryonated chicken eggs (SPF-ECE), detection using AGID and RT-PCR. Ten samples showed positive results with egg isolation, AGID and RT-PCR. Sequence analysis and characterization of the variable region of VP2 gene purified from the PCR product showed many amino acid substitutions that may affect IBDV antigenicity and virulence. Comparative phylogenetic analysis based on the sequence of the hypervariable region of VP2 gene clustered the isolated IBDV at a distance from the other reference IBDV from Egypt, Europe and other vaccinal strains. It was concluded that substitution mutations observed with the hypervariable region of VP2 gene of the isolated IBDV could affect the virus antigenicity and further studies on the efficacy of vaccines used locally against this variant IBDV strain have to be investigated.

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Bovine herpesvirus 1 (BoHV-1), an important bovine pathogen, establishes lifelong latency in sensory neurons within trigeminal ganglia (TG). Stress, as mimicked by the synthetic corticosteroid dexamethasone, consistently induces reactivation in calves latently infected with BoHV-1. Dexamethasone induces expression of several transcription factors in TG neurons during early stages of reactivation, including Krüppel-like transcription factors (KLF): KLF4, KLF6, KLF15, and promyelocytic leukemia zinc finger. Furthermore, the glucocorticoid receptor (GR) is consistently detected in TG neurons expressing viral regulatory proteins during reactivation from latency. The viral immediate early transcription unit 1 (IEtu1) promoter that drives expression of two viral transcription factors (bICP0 and bICP4) contains two GR response elements (GREs) and is stimulated by DEX. KLF15 and the GR form a feed forward transcription loop that synergistically stimulates productive infection and IEtu1 promoter activity. New studies demonstrate the GR and KLF6 synergistically stimulate productive infection and IEtu1 promoter activity if the GREs are intact. Furthermore, the GR and KLF6 interact with wild-type GREs within the IEtu1 promoter, but not GRE mutants. These studies suggest that certain KLF family members and the GR can convert a silent viral genome in latently infected neurons into an actively transcribing genome during reactivation from latency.

Vaccination is one of the control measures of the disturbing Newcastle Disease in Egypt. Inactivated Newcastle Disease virus (NDV) vaccine was prepared using a local isolate (NDV-ch-EG-CLEVB-F604-2016), from Qaliobia governorate, Egypt, with Montanide ISA70VG as an oil adjuvant. The prepared vaccine was evaluated in comparison with an inactivated imported vaccine. Chick and Turkey chick groups vaccinated with either prepared or imported vaccines showed high serum antibody titers from the 3rd week post vaccination and reached the highest titer at the 9th week post vaccination using HI test. Both prepared and imported vaccines gave near percentage of protection against the local and the classical strain in both groups of chicks and turkeys ,21 days post vaccination, with no clinical signs or lesions on examination. Concluding that the locally prepared inactivated NDV vaccine can protect chicken and turkey against both homologous and heterologous challenging viruses.