Confirmed spread of Vibrio parahaemolyticus by aerosols is a risk factor in the infection of shrimp ponds

This study investigated the aerial transmission of Vibrio parahaemolyticus (VpAHPND), the causative agent of acute hepatopancreatic necrosis disease in whiteleg shrimp (Penaeus vannamei). Using aerated tanks inoculated with 1 × 10⁶ CFU/mL VpAHPND and a lateral airflow of 9.81 km/h, bacterial dispersal was evaluated across experimental arenas using TCBS agar plates. Viable bacteria released at 43 cm and 220 cm above ground were detected up to 20 m away, with extrapolated dispersal distances reaching 27.38 m and 72.92 m, respectively. A 1.5 m tarpaulin barrier positioned 5 m from the source failed to halt transmission, as bacteria traveled around it and colonised plates up to 5.5 m behind the barrier. However, combining an aeration cover with two layers of 85% shade netting reduced bacterial penetration 20- to 30-fold. Sentinel monitoring at a commercial shrimp farm confirmed the presence of airborne VpAHPND around infected grow-out ponds and wastewater reservoirs via qPCR. These findings prove that pond aerators generate infectious bioaerosols that can disseminate over tens of meters, underscoring the urgent need to integrate airborne pathogen control, airflow management, and physical screening into shrimp farm biosecurity protocols.