Efficacy of the Newcastle Disease Virus Genotype VII.1.1-Matched Vaccines in Commercial Broilers

Hesham A Sultan; Wael K Elfeil; Ahmed A Nour; Laila Tantawy; Elsayed G Kamel; Emad M Eed; Ahmad El Askary; Shaimaa Talaat

doi:10.3390/vaccines10010029

Efficacy of the Newcastle Disease Virus Genotype VII.1.1-Matched Vaccines in Commercial Broilers

Vaccines (Basel). 2021 Dec 27;10(1):29. doi: 10.3390/vaccines10010029.

Authors

Hesham A Sultan¹, Wael K Elfeil², Ahmed A Nour³, Laila Tantawy⁴, Elsayed G Kamel¹, Emad M Eed⁵, Ahmad El Askary⁵, Shaimaa Talaat¹

Affiliations

¹ Department of Birds and Rabbits Medicine, Faculty of Veterinary Medicine, University of Sadat City, Menoufiya 32958, Egypt.
² Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 51522, Egypt.
³ Agriculture Research Center, National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Giza 12566, Egypt.
⁴ Agriculture Research Center, Pathology Department, Animal Health Research Institute, Giza 12566, Egypt.
⁵ Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.

Abstract

Class II genotype VII Newcastle disease viruses (NDV) are predominant in the Middle East and Asia despite intensive vaccination programs using conventional live and inactivated NDV vaccines. In this study, the protective efficacies of three commercial vaccine regimes involving genotype II NDV, recombinant genotype VII NDV-matched, and an autogenous velogenic NDV genotype VII vaccine were evaluated against challenge with velogenic NDV genotype VII (accession number MG029120). Three vaccination regimes were applied as follows: group-1 received inactivated genotype II, group-2 received inactivated recombinant genotype VII NDV-matched, and group-3 received velogenic inactivated autogenous NDV genotype VII vaccines given on day 7; for the live vaccine doses, each group received the same live genotype II vaccine. The birds in all of the groups were challenged with NDV genotype VII, which was applied on day 28. Protection by the three regimes was evaluated after infection based on mortality rate, clinical signs, gross lesions, virus shedding, seroconversion, and microscopic changes. The results showed that these three vaccination regimes partially protected commercial broilers (73%, 86%, 97%, respectively, vs. 8.6% in non-vaccinated challenged and 0% in non-vaccinated non-challenged birds) against mortality at 10 days post-challenge (dpc). Using inactivated vaccines significantly reduced the virus shedding at the level of the number of shedders and the amount of virus that was shed in all vaccinated groups (G1-3) compared to in the non-vaccinated group (G-4). In conclusion, using closely genotype-matched vaccines (NDV-GVII) provided higher protection than using vaccines that were not closely genotype-matched and non-genotype-matched. The vaccine seeds that were closely related to genotype VII.1.1 provided higher protection against challenge against this genotype since it circulates in the Middle East region. Updating vaccine seeds with recent and closely related isolates provides higher protection.

Keywords: Newcastle disease virus; commercial broiler; genotype-matched vaccine; inactivated vaccine; maternal derived immunity.

Grants and funding

TURSP-2020/157/Taif University Researchers Supporting Project