PROTECTIVE EFFICACY OF COMMERCIAL NEW CASTLE DISEASE VACCINES AGAINST VIRULENT GENOTYPE VII NEWCASTLE DISEASE VIRUS

Ahmed, Hasnaa; Khodier, Mohamed; Kasem, Samy; El-Gohary, Abd El-Galil

doi:10.21608/kvmj.2017.112753

PROTECTIVE EFFICACY OF COMMERCIAL NEW CASTLE DISEASE VACCINES AGAINST VIRULENT GENOTYPE VII NEWCASTLE DISEASE VIRUS

Document Type : Original Article

Authors

¹ Department of Virology, Faculty of Veterinary Medicine, Kafrelsheikh University

² Veterinary Serum and Vaccine Research Institute, Abbasia, Cairo, Egypt

³ Department of Poultry Diseases, Faculty of Veterinary Medicine, Kafrelsheikh University

10.21608/kvmj.2017.112753

Abstract

Despite the widespread use of different types of vaccines, Newcastle disease continues to be a major threat in poultry industry that emphasizes the importance of continued research on vaccine efficacy against newly isolated strains. Our study assessed whether
a virulent genotype VII NDV field isolate can overcome the immunity of chickens induced by the currently used ND vaccines after different vaccination schemes in Egypt. Two hundred Cobb chicks (one day old) obtained from Alwatania Poultry Company Egypt branch were used , Chicks were divided into four groups (n=50 per group), Group I: Ten chicks used for measuring maternal immunity at day one of age, And 40 chicks kept asa control group, and they were divided into 4 subgroups ten for each, three subgroups (30 chicks) were used as positive control and they were vaccinated with the same vaccines of the experimental groups but without challenge, and the last ten chicks were kept unvaccinated to be used as negative control. Other three groups besides those of group I (control group) were primary immunized with Hitchner-B1 at day 7, then subjected to the following vaccines at day 14 as follow, Group II was immunized via eye dropping with commercial live LaSota vaccine. Group IIII was immunized via eye dropping with commercial live Clone-30 vaccine. Group IV was immunized via eye dropping with commercial live ND 6/10 vaccine. Experimental challenge of the different groups revealed death of all 10 challenged birds of the negative control group, death of 12 out of 50 challenged birds in group-II; 14 out of 50 challenged birds in group-III; 9 out of 50 birds in group-IV. Recent studies and ours revealed that prevalent genotype VII differ from widely used vaccine strains in its genetics, immune response and protective efficacy. So, further studies on antigenic characters of recent NDV isolate and protective efficacy of currently used NDV vaccines against it are needed.

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