Research Article Isolation and Metagenomic Identification of Avian Leukosis Virus Associated with Mortality in Broiler Chicken Faruku Bande, 1,2 Siti Suri Arshad, 1 and Abdul Rahman Omar 1,3 1 Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor Darul Ehsan, Malaysia 2 Department of Veterinary Services, Ministry of Animal Health and Fisheries Development, PMB 2109, Usman Faruk Secretariat, Sokoto 840221, Sokoto State, Nigeria 3 Laboratory of Vaccine and Immunotherapeutic, Institute of Bioscience, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor Darul Ehsan, Malaysia Correspondence should be addressed to Siti Suri Arshad; suri@upm.edu.my and Abdul Rahman Omar; aro@upm.edu.my Received 19 April 2016; Accepted 29 June 2016 Academic Editor: Finn S. Pedersen Copyright © 2016 Faruku Bande et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Avian leukosis virus (ALV) belongs to the family Retroviridae and causes considerable economic losses to the poultry industry. Following an outbreak associated with high mortality in a broiler lock in northern part of Malaysia, kidney tissues from afected chickens were submitted for virus isolation and identiication in chicken embryonated egg and MDCK cells. Evidence of virus growth was indicated by haemorrhage and embryo mortality in egg culture. While viral growth in cell culture was evidenced by the development of cytopathic efects. he isolated virus was puriied by sucrose gradient and identiied using negative staining transmission electron microscopy. Further conirmation was achieved through next-generation sequencing and nucleotide sequence homology search. Analysis of the viral sequences using the NCBI BLAST tool revealed 99-100% sequence homology with exogenous ALV viral envelope protein. Phylogenetic analysis based on partial envelope sequences showed the Malaysian isolate clustered with Taiwanese and Japanese ALV strains, which were closer to ALV subgroup J, ALV subgroup E, and recombinant A/E isolates. Based on these indings, ALV was concluded to be associated with the present outbreak. It was recommended that further studies should be conducted on the molecular epidemiology and pathogenicity of the identiied virus isolate. 1. Introduction Avian leukosis virus (ALV) is an economically important retrovirus afecting meat and egg-type chicken. he virus belongs to an Alpharetrovirus genus in the family Retroviri- dae. Based on the envelope glycoprotein (gp85) it was possible to classify exogenous ALV into diferent subgroups, namely, A, B, C, D, E, and J. Particularly, the viral envelope glycopro- tein is responsible for attachment and receptor speciicity as well as the production of neutralizing antibodies [1, 2]. Of the viral subgroups so far identiied, subgroups A, B, and J are considered most prevalent and more economically important [3]. Subgroup J was irst isolated in meat-type chicken in the United Kingdom in 1989 but currently is causing devastation to poultry industry worldwide [4]. Apart from its immunosuppressive efect, ALV is commonly associated with lymphoid leukosis, myelocytic myeloid leukosis, and renal as well as other forms of tumours [5]. his study reports some virological and molecular sequencing approaches used to identify the viral cause of mortality in a broiler lock in Malaysia. 2. Materials and Methods Following a suspected outbreak in a broiler chicken farm with capacity of about 10,000 birds, tissue samples, including trachea, kidney, and proventriculus, were submitted to the virology laboratory, Universiti Putra Malaysia, for virus iso- lation and identiication. he mortality rate was reported to reach about 10% in the 27-day-old lock ( = 6000) and more than 20% in the 30-day-old lock ( = 4000). he chickens Hindawi Publishing Corporation Advances in Virology Volume 2016, Article ID 9058403, 4 pages http://dx.doi.org/10.1155/2016/9058403