Advances in Diagnostic Technologies of Major Avian Respiratory Viruses: A Review

Abstract

Simple Summary Avian respiratory diseases caused by avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and infectious laryngotracheitis virus (ILTV) are major threats to the global poultry industry and to public health. Because these viruses cause similar clinical signs, often occur as co-infections, and mutate rapidly, fast and accurate diagnosis is essential for disease control and surveillance. This review summarizes current advances in molecular and immunological diagnostic technologies for these four viruses, including real-time PCR and multiplex assays, isothermal amplification methods, CRISPR-based detection, high-throughput sequencing, and immunoassays using recombinant proteins, nanobodies, and immunochromatographic strips (ICS). We compare the strengths and weaknesses of these technologies and discuss future trends toward integrated, automated, and connected diagnostic systems. The review aims to help researchers, veterinarians, and policymakers select appropriate diagnostic tools for outbreak investigation, routine surveillance, vaccination monitoring, and export certification, and to support more efficient surveillance and early-warning systems.