Isolation, identification and molecular characterization of Newcastle disease viruses in vaccinated chickens from commercial farms in the Sultanate of Oman

Abstract

Newcastle disease (ND) remains an important enzootic disease in chickens in several parts of the world. With the increasing reports of virulence and genetic diversity of the causative agent; Newcastle disease virus (NDV), there is a need to identify the circulating NDV in specific regions. In Oman, to this moment, such information is still lacking. The aim of this study was to isolate and characterize the NDV from ND outbreaks from commercial farms in Oman. Following suspected outbreaks of ND in three commercial farms in 2017, a total of 30 carcasses (10 from each flock) of adult chickens were subjected to necropsy for gross and histopathological examination, virus isolation and molecular methods. Specifically, haemagglutination inhibition (HI) test and reverse transcription-polymerase chain reaction (RT-PCR) assay were used for the virus detection and confirmation, respectively. Lesions were suggestive of viscerotropic velogenic form of ND based on gross and histopathological examinations. Isolation of NDV was present in 4 cases and further confirmed by RT-PCR following the target of the partial fusion protein gene of the viral genome. The sequence of the partial fusion gene was determined and phylogenetic tree was constructed based on the partial length F gene of 4 Omani isolates and 65 previously published NDVs. The findings predicted that the Omani isolates had high homology (99%) with the isolate from Pakistan belonging to genotype VII. Subsequently, the isolated pathotype was identified as the virulent NDV. This study serves as a basic work for further research on the analysis and phenotyping of NDV in the Sultanate of Oman. Improved monitoring and surveillance of the disease is important for proper preventive measures.

Molecular Detection and Characterization of Newcastle Disease Virus from Chickens in Mid-Rift Valley and Central Part of Ethiopia

“…26 NDV strain vaccine with ON033824 isolates, isolated from the currently used vaccine for commercial and village chickens in Ethiopia belonged to the lentogenic genotype II and was found to show higher similarity (96.76%) to the HB1 vaccine strain genotype (MK796810.1) and LaSota vaccine strain genotype (MK310259.1) of vaccines in-use in India and Pakistan. In this study, the findings of the phylogenetic analysis are consistent with the report of several researchers, [27][28][29][30] showing the continuous evolution and mutation in the partial region of F gene in NDV strain genotype.…”

Analysis of Amino Acid Changes in the Fusion Protein of Virulent Newcastle Disease Virus from Vaccinated Poultry in Nigerian Isolates

“…Existing antigenic variations among West Africa strains and the LaSota vaccine may affect its protective efficacy to confer protection against all West African strains [ 33 ]; in cases where the LaSota vaccine provided protection against clinical disease, it did not prevent infection and viral shedding [ 33 ]. Although all NDV strains belong to one serotype, protection provided by genotype II vaccines against heterologous challenge has been recently under controversy [ 31 ] with several reports of LaSota vaccine failing to provide complete protection against morbidity and or mortality during experimental heterologous vNDV challenge necessitating the growing need for development of antigenically matched vaccines to circulating strains [ 12 ].…”

“…Although Newcastle disease (ND) is said to be enzootic in Nigeria, little information exists on the molecular epidemiology and the lineage distribution of the Newcastle disease virus (NDV) in the country [ 3 ] and there is paucity on reports of virulent Newcastle disease virus (vNDV) strains obtained from dead/sick vaccinated animals in the outpatient veterinary clinic. The importance of detection and pathotyping of NDV in understanding the epizootiology of the virus in any region cannot be overemphasized [ 12 ] especially with the growing need for evaluation of the efficacy of existing ND vaccines [ 13 ]. Presently, two live attenuated monovalent vaccines—LaSota and Komarov—are commercially available for the control of ND in intensively reared poultry in Nigeria, but there are reports of ND outbreak among vaccinated flocks.…”

Exposure assessment for avian influenza and Newcastle disease viruses from peridomestic wild birds in a conservation breeding site in the United Arab Emirates

“…In the Middle East, despite the arid environment, unfavourable weather conditions and limited populations of wild waterfowl, AIV and NDV are regularly detected in poultry (Aamir et al., 2007; Al Shekaili et al., 2015; Al‐Azemi et al., 2008; Alkhalaf, 2010; A. A. Alsahami et al., 2018; A. Alsahami et al., 2018; Haroun et al., 2015; Hirschinger et al., 2019; Kent et al., 2006; Khan et al., 2009; Mohran et al., 2011; Nagy et al., 2017; Naldo & Samour, 2004; Obon et al., 2009; Wernery et al., 2013). In the United Arab Emirates (UAE), the poultry industry is an important sector, especially broiler and layer chickens (Seifarth & Tarraf, 2018).…”