Quantifying aerosol transmission distance for foot-and-mouth disease virus

Foot-and-mouth disease (FMD) is an acute, febrile, and highly contagious animal infectious disease that can be transmitted through multiple routes. Among these, aerosol transmission of foot-and-mouth disease virus (FMDV) represents a particularly complex transmission pathway and plays a significant role in viral dissemination. To elucidate the environmental transmission mechanisms of FMDV aerosols, this study establishes a spatiotemporal dynamic model to characterize the emission, diffusion, sedimentation, and migration processes of FMDV aerosols released by infected livestock (cattle, sheep, or pigs) or infected farm. Through comprehensive model analysis and numerical simulations, we investigate the spatial distribution patterns of FMDV emitted from infected animals or infected farm, and quantify its transmission distances. Key findings demonstrate that under stable atmospheric conditions without significant wind currents, the effective aerosol transmission distance from an infected pig is limited to < 7 m, with cattle/sheep showing no aerosol transmission capability to pigs. When wind velocity reaches 0.1 m/s, the 24-hour effective transmission distance extends to 10 km for infected pigs, while infected cattle/sheep can transmit up to 8 km to cattle, 6 km to sheep and 2 km to pigs. Under sustained 0.1 m/s wind conditions, our farm-scale modeling reveals a linear temporal expansion of FMDV aerosol dispersion, seven-day maximum transmission distances from an introduced infection were: cattle farms ($6.2-12.07$ km), sheep farms ($4.8-10.8$ km), and pig farms ($17-22.68$ km).