Zoonotic diseases transmitted through interconnected networks of humans, animals, and the environment are intensifying global public health and biosecurity threats under the One Health paradigm. Conventional diagnostic methods— including microbial culture, serological testing, and PCR-based molecular assays—are accurate but time-consuming, equipment-dependent, and difficult to implement in field settings. In this context, CRISPR-based nucleic acid diagnostics have emerged as an innovative tool that enables rapid, sensitive, and specific detection with minimal instrumentation. This review provides a comprehensive overview of CRISPR systems and their diagnostic mechanisms, with a focus on point-of-care detection of zoonotic pathogens such as SARS-CoV-2, Salmonella spp., Listeria monocytogenes, Bacillus anthracis, Brucella spp., Mpox virus, and avian influenza virus. It also discusses field-deployable technologies, including digital CRISPR assays, one-tube platforms, electrochemical biosensors, and portable diagnostic systems aligned with WHO ASSURD criteria. In addition, the review examines practical considerations for applying CRISPR-based diagnostics in veterinary and food safety settings, including reagent stabilization, matrix compatibility, multiplex detection, and integration with data systems. Collectively, these advances position CRISPR diagnostics as a cornerstone of precision disease surveillance and early intervention within the One Health framework. This innovation heralds a new era of intelligent preventive veterinary medicine that aims to break zoonotic transmission cycles and ensure sustainable biosecurity.