Comparative Efficacy of Genotype-Matched and Conventional Vaccines Against Newcastle Disease Virus Genotype VII in Broilers

Mahmoudzadeh Akhijahani, Mohsen; Ghalyanchi Langeroudi, Arash; Abdolshah, Mohammad; Fallah Mehrabadi, Mohammad Hossein; Ziafati Kafi, Zahra

doi:10.22092/ari.2026.372328.4076

Comparative Efficacy of Genotype-Matched and Conventional Vaccines Against Newcastle Disease Virus Genotype VII in Broilers

Articles in Press

Document Type : Original Articles

Authors

¹ Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

² Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

10.22092/ari.2026.372328.4076

Abstract

Background:
Newcastle disease (ND) is one of the most economically significant diseases in the poultry industry. In Iran, the disease is endemic and frequently causes outbreaks with high mortality and severe clinical signs, predominantly associated with genotype VII strains. The poultry industry in Iran is essential for food security and economic stability; however, viral diseases, particularly Newcastle disease, pose a major threat by causing significant production losses and economic damage. The aim of this study was to evaluate the serological and performance efficacy of the MEVAC RINNOVAC Eli-7 and MEVAC ND7 PLUS vaccines.
Methods:
A total of 150 commercial LSL layer cockerels were divided into six groups and maintained under identical conditions. Birds were vaccinated at 14 days of age with live or inactivated NDV vaccines. Blood samples were collected on days 0, 14, and 21 post-vaccination to evaluate serological responses using the HI test. On day 21 post-vaccination, birds were challenged with a circulating NDV genotype VII strain, and clinical signs, viral shedding (via RT-PCR), and pathological changes were monitored. Molecular and phylogenetic analyses of the fusion (F) gene were performed to confirm vaccine strain identity.
Results:
Both MEVAC ND7 PLUS and MEVAC RINNOVAC Eli-7 vaccines elicited robust serological responses by day 21 post-vaccination, with antibody titers significantly higher than those of the unvaccinated control and comparable to conventional vaccines. Following the challenge on day 28, vaccinated birds maintained high antibody levels and showed no clinical or histopathological lesions, whereas control birds did not survive. Vaccine uptake assessed by RT-PCR on day 5 post-vaccination was undetectable in all groups.
Conclusion:
Both MEVAC RINNOVAC Eli-7 and ND7 PLUS vaccines effectively induced protective immunity, reduced viral replication and shedding, and elicited robust antibody responses against NDV genotype VII. These results underscore the value of genotype-matched vaccination as a key strategy for controlling Newcastle disease and minimizing its economic impact in poultry.

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