Genetic Diversity of Newcastle Disease Virus and Its Implications for Vaccine Development

The Newcastle disease virus (NDV), an avian paramyxovirus, induces the highly contagious Newcastle disease in poultry. Newcastle disease outbreaks, common in many developing countries, have been recorded worldwide for a century. Poultry, even vaccinated stocks, together with wild and synanthropic birds, serve as reservoirs of NDV. Despite the extensive use of commercial NDV vaccines, Newcastle disease outbreaks frequently occur in vaccinated chickens, resulting in great economic losses. The primary limitation of commercial Newcastle disease vaccines is their restricted compatibility with emerging novel NDV strains. The advancement of vaccines and vaccination techniques is anticipated to reduce the propagation of pathogenic NDV strains and consequently alleviate losses in poultry production. This review examines the NDV genotypes and strains implicated in both current and historical Newcastle disease outbreaks, and evaluates existing and candidate NDV vaccines, emphasizing recent innovations and novel techniques. Our aim was to delineate critical subjects for future inquiry and to furnish extensive data that could aid researchers in understanding the current advancements and existing problems in Newcastle disease vaccination prophylactics. The emergence of a new generation of vaccines employing advanced technologies may substantially improve the efficacy of Newcastle disease prevention and control.