Isolation and Molecular Characterization of Marek’s Disease Virus from Layer Chickens in Egypt

Document Type : Full-length article


1 Department of Virology, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 62511, Egypt

2 National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza-12618, Egypt

3 Animal Health Research Institute, Mansoura branch, Egypt


Marek’s disease virus is a lymphomatous neuropathic disease of domestic fowl. In Egypt, poultry flocks are suffering from recurrent uprising of MD outbreaks due to increased virulence of the virus. In this study, a total of 10 clinical samples were collected from 6-8 months old vaccinated layer chickens suffering from depression, ataxia and paralysis. These samples were examined for the presence of MDV by PCR using specific primers for ICP4 gene. MDV was detected in 5 out of 10 samples. One out of the 5 positive samples was isolated and partially sequenced for ICP4 gene (F1352-S4).  The results proved that it was genetically characterized as very virulent strain of Marek's disease virus type 1 resembling Gallid herpesvirus 2 isolates from Europe, China, Africa and India. There was a characteristic serine residue at the coding region of ICP4 gene encoding the reverse complement protein found only in the Egyptian virus (F1352-S4) and EU-1 virus, IND-KA-02-06, JL/1404 and in Debre-zeit/01/2013 virus that is tracing for the original virus CV1988. The obtained results indicated the importance of continuous monitoring of MDV infection in chicken layer flocks.


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