Efficacy of inactivated velogenic Newcastle disease virus genotype VII vaccine in broiler chickens.

Autor: Fawzy M; Department of Virology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt., Ali RR; Organization of Public Veterinary Services, Ismailia, Egypt., Elfeil WK; Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt., Saleh AA; Veterinary Serum and Vaccine Research Institute, Abbassia, Cairo, Egypt., El-Tarabilli MMA; Department of Virology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt.
Jazyk: angličtina
Zdroj: Veterinary research forum : an international quarterly journal [Vet Res Forum] 2020 Spring; Vol. 11 (2), pp. 113-120. Date of Electronic Publication: 2020 Jun 15.
DOI: 10.30466/vrf.2019.95311.2295
Abstrakt: Newcastle disease (ND) causes severe economic losses in poultry production. Despite the intensive vaccination regimes of NDV in Egypt, many outbreaks are being reported. The present study focused on the preparation and evaluation of inactivated velogenic Newcastle disease virus vaccine (genotype VII) isolated from Egyptian broiler chicken during 2015-2016. Fifty-five tissue samples including trachea, lung, liver, proventriculus, intestine, and kidney collected from commercial broiler chickens were used for virus isolation in specific pathogen-free embryonated chicken eggs (ECE) and identified using RT-PCR and sequencing. The isolates were classified by sequencing as velogenic NDV genotype VIId containing F0 protein cleavage site motifs ( 112 RRQKRF 117 ). A selected isolate was served as a master seed for the preparation of inactivated NDV vaccine with or without Montanide ISA70 adjuvant and evaluated in SPF chicks. Nine NDV isolates were isolated on ECE and the highest infectivity titer of the virus was 7.50 log 10 EID 50 mL -1 by the 5 th passage. Vaccinated chicks with NDV-Montanide ISA70 adjuvanted vaccine exhibited antibody titer of 5.20 log 2 at the 3 rd -week-post-vaccination (WPV) with the highest titer (8.90 log 2 mL -1 ) at the 6 th -WPV. Protective antibodies values were persisted to 12 th WPV followed by a gradual decrease to the end of the experiment (16 th weeks). Vaccination of chicks with inactivated NDV isolate without adjuvant failed to induce protective HI antibodies all over the experiment. Chickens vaccinated with the ISA70 adjuvant vaccine were passed homologous challenge tests with 100% protective efficiency, while the unadjuvanted vaccine could not provide any protective efficiency. In conclusion, the preparation of inactivated oil adjuvant vaccine from NDV field circulating strains was efficient in controlling the disease in Egypt.
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Databáze: MEDLINE
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