Comprehensive review of diagnostic concepts of major respiratory viruses (avian influenza virus, infectious bronchitis virus, Newcastle disease virus, infectious laryngotracheitis virus, and avian metapneumoviruses) in poultry

The rapid detection and differentiation of major respiratory viruses, such as avian influenza, infectious bronchitis virus, Newcastle disease virus, infectious laryngotracheitis virus, and avian metapneumoviruses within an infected poultry flock, are crucial for timely control measures. Effective disease management mandates identifying the etiologic agent and differentiating between similar pathogens in the early stages of infection. The traditional methods of virus detection include virus isolation, virus neutralization, and hemagglutination inhibition assays. Molecular-based methods, such as quantitative real-time polymerase chain reaction (PCR), have also become a standard. Future diagnostic concepts focus on advances in point-of-care testing that can be applied directly on-site in poultry plants, such as biosensing and lateral flow tests, which are becoming prominent in avian diagnostics. Portable PCR assays, such as loop-mediated isothermal amplification, are also becoming popular. In addition, artificial intelligence, particularly those using deep-learning techniques, is increasingly being integrated into early disease detection. This comprehensive review examines the history of diagnostic methodologies that have supported these efforts for decades and discusses future concepts and trends in the field.