Surveillance of zoonotic respiratory viral infections in animal farms: a model project with a focus on One Health approach-A study protocol.

BACKGROUND: The One Health approach recognizes the interconnectedness of human, animal, and environmental health in addressing the growing threat of zoonotic diseases. This study aims to establish an integrated One Health surveillance system for the early detection and monitoring of zoonotic respiratory viral infections at the human-animal-environment interface in Tiruvallur District, Tamil Nadu, India. OBJECTIVES: The study aims to establish a longitudinal surveillance system for the early detection of emerging and re-emerging zoonotic respiratory viral infections across livestock animals, animal handlers, and the farm environment interface; and ii) determine the occurrence and distribution of selected zoonotic respiratory viruses, and assess the influence of seasonal and climatic factors on their occurrence and transmission. METHODS: Following sensitization of farm owners and animal handlers through the Animal Husbandry Department, 40 livestock farms from four selected blocks of Tiruvallur District, rearing cattle, buffalo, goats, sheep, swine, and poultry, will be enrolled in each surveillance round. Animal nasal swabs, respiratory samples from animal handlers, and environmental samples (air and wastewater) will be collected. Field surveillance will be carried out by a study team comprising a veterinarian and field investigators. Sixteen surveillance rounds (eight rounds annually) will be conducted over 2 years, covering two complete climatic cycles. Approximately 7,360 animal swab samples, 960 samples from animal handlers, and 960 environmental samples will be collected in each study phase. Animal samples will be screened using a pooled testing strategy followed by real-time RT-PCR for the detection of selected zoonotic respiratory viruses, while human samples will be tested individually. EXPECTED OUTCOMES: The study is expected to establish a robust One Health surveillance framework and generate baseline epidemiological data on zoonotic respiratory viruses circulating among livestock, animal handlers, and the farm environment in Tamil Nadu. The findings will strengthen integrated surveillance, support early warning systems, facilitate timely veterinary and public health responses, and provide evidence to inform future One Health policies and preparedness strategies for emerging zoonotic respiratory viral infections.