Superior Efficacy of Apathogenic Genotype I (V4) over Lentogenic Genotype II (LaSota) Live Vaccines against Newcastle Disease Virus Genotype VII.1.1 in Pathogen-Associated Molecular Pattern-H9N2 Vaccinated Broiler Chickens

Abstract

A comparison of the efficacy of apathogenic genotype I (V4) and lentogenic genotype II (LaSota) strains of live Newcastle disease virus (NDV) vaccines was performed following vaccination with pathogen-associated molecular pattern (PAMP) H9N2 avian influenza vaccine and challenge with velogenic NDV genotype VII.1.1 (vNDV-VII.1.1). Eight groups (Gs) of day-old chicks were used (n = 25). Groups 1–4 received a single dose of PAMP-H9N2 subcutaneously, while Gs (1, 5) and (2, 6) received eye drops of V4 and LaSota, respectively, as two doses. All Gs, except for 4 and 8, were intramuscularly challenged with vNDV-VII.1.1 at 28 days of age. No signs were detected in Gs 1, 5, 4, and 8. The mortality rates were 0% in Gs 1, 4, 5, and 8; 40% in G2; 46.66% in G6; and 100% in Gs 3 and 7. Lesions were recorded as minimal in Gs 1 and 5, but mild to moderate in Gs 2 and 6. The lowest significant viral shedding was detected in Gs 1, 2, and 5. In conclusion, two successive vaccinations of broilers with a live V4 NDV vaccine provided higher protection against vNDV-VII.1.1 challenge than LaSota. PAMP-H9N2 with live NDV vaccines induced more protection than the live vaccine alone.

Isolation and molecular characterization of velogenic Newcastle disease virus genotype VII.1.1 from commercial broilers and wild birds in Matrouh governorate, Egypt

“…The partial F gene sequences (1-149) of 2 obtained vNDV (OR778089 and OR778090) showed 100% identity with the previous isolates of vNDV-VII.1.1 in Egypt during 2016-2020, sharing the same cleavage site motif of RRQKRF at positions (112-117 aa), and had 77.9-82.7% similarity with the genotypes I and II that are used as commercial vaccines in Egypt. Recently, an attractive research work that was done by Elbestawy et al (2023) showed superior efficacy of apathogenic genotype I (V4) over lentogenic genotype II (LaSota) live vaccination against vNDV-VII.1.1 in broiler chickens that were vaccinated with a pathogen-associated molecular pattern H9N2 inactivated vaccine. They confirmed the theory explained by Tabatabaeizadeh (2021), who mentioned that the higher the match of linear and conformational neutralizing epitopes of F and HN proteins (n = 15) of the vaccine strains and vNDV-VII.1.1 (V4 = 14 > LaSota = 7), the higher obtained protection in the vaccinated birds.…”