Characterization of Avian Influenza H9N2 and Newcastle Disease Virus Isolated from Vaccinated Chickens in Upper Egypt | ||
| Journal of Veterinary Medical Research | ||
| Article 9, Volume 27, Issue 1, June 2020, Pages 90-108 PDF (1.77 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jvmr.2020.25519.1007 | ||
| Authors | ||
| Safaa A. A. Abdel-Latif1; Asmaa Atef2; Ahmed M. A. Abdel-Aleem3; AL-Hussien M. Dahshan4; Ahmed Ali4 | ||
| 1Directorate of Veterinary Medicine in Minia, General Organization of Veterinary Services, Ministry of Agriculture, Egypt | ||
| 2General Administration of Student Housing Facilities, Fayoum University, Egypt. | ||
| 3General Administration of student housing facilities, Beni Suef University, Beni Suef 62511 Egypt. | ||
| 4Poultry Diseases Department, Faculty of Veterinary Medicine, Beni Suef University, Beni Suef 62511 Egypt. | ||
| Abstract | ||
| In this study, 50 vaccinated broiler and one layer flock from Beni-Suef, Fayoum and Minia governorates were investigated. Necropsy lesions were suggestive of LPAI-H9N2 or NDV. Samples of tracheal swabs and organs were subjected for viral isolation and molecular characterization. Specific RT-PCR for the NDV F-gene and the HA gene of the LPAI-H9N2 viruses was used. Virus isolation and primary identification using HI test revealed 37.5 and 43.3-46.2% prevalence for LPAI-H9N2 and NDV viruses, respectively. Phylogenetic analysis of partial sequences of the F gene showed that NDV viruses belong to genotype II and VII-1.1. as indicated by the F0 protein proteolytic cleavage site motifs (aa112-117) of the NDV strains F-gene. The vNDV isolates were 98.7-99.3% and 96.6-98.9% identical to each other based on nucleotide and amino acid identities, respectively. Compared to their counterpart isolates; the lentogenic strains shared 98-99.2% and 96.3-98.1% nucleotide and amino acid identities to the LaSota reference strain. The LPAI-H9N2 phylogeny of the HA gene showed that the 2 isolates obtained in this study are related to each other and related to recent 2016-2018 Egyptian H9N2 strains. Notably, the 2 strains showed higher identity (≥99%) to recent Israeli 2018 isolates with several amino acid changes. The current study revealed wide spread of both NDV and LPAI-H9N2 viruses. The vaccine failure and the mismatch between the vaccine and circulating NDV viruses is the most probable cause of current outbreaks. The LPAI-H9N2 viruses are divergent form their ancestral viruses in Egypt indicating continuous circulation and vaccine pressure induced mutations | ||
| Keywords | ||
| Broiler; H9N2; NDV; Surveillance; Egypt | ||
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