The Vaccine and Infectious Disease Organization (VIDO), a global leader in infectious disease and vaccine development for humans and animals, conducted a controlled infectivity study in dairy cows to assess H5N1 virus shedding and potential aerosol transmission. Inoculated cows exhibited clinical signs consistent with those observed in affected dairy herds in the United States, with peak virus shedding occurring between days 2 and 4 post-inoculation (DPI), and tapering off by Day 21.
To evaluate whether infectious material was present in the air during routine farm activities, AirPrep™ Cub Samplers were deployed in the animal rooms to simulate high-risk aerosolization scenarios. Samplers were positioned approximately 1.5 meters above the floor, out of the animals’ reach, and operated at 200 L/min for three continuous hours following evening milking and during power washing of the floor. This setup aimed to replicate typical cleaning procedures in a milking parlor where airborne transmission risk may be elevated.
Captured material on the AirPrep™ electret filters was eluted using InnovaPrep’s Wet Foam Elution™ protocol. Despite the high ventilation rates of the CL3 large animal facilities (≥15 air exchanges per hour), HPAI H5N1 viral RNA was successfully detected in the air samples. Cycle threshold (Ct) values ranged from 32–37 across different sampling timepoints, including DPI 2, 3, and 4 during both routine animal activity and post-cleaning procedures.
These findings demonstrate that routine on-farm activities involving infected dairy cows can generate bioaerosols containing viral RNA. Notably, the viral RNA levels detected in this controlled, highly ventilated environment likely underestimate the potential exposure in typical agricultural settings.
This study underscores the importance of thoughtful timing, sampler placement, and equipment selection when designing air sampling strategies for experimental models and real-world agricultural surveillance of airborne pathogens.
Read the Publication:
Dairy cows develop protective immunity against reinfection with bovine H5N1 influenza virus, Antonio Facciuolo, et al. Nature Microbiology 2025
Resource: Strategies for Monitoring Airborne Disease Pathogens in Livestock Settings
