Epidemiology of human contacts of equine Hendra virus infection in northern New South Wales, Australia, 2006–2023

Objectives: Hendra virus is an important zoonotic pathogen in Australia, with widespread presence in flying fox reservoirs and serious health consequences for horses and humans. This study describes the epidemiology of all human contacts of confirmed Hendra virus cases in New South Wales (NSW) to inform future public health responses. Methods: A cross-sectional study was conducted of all known human contacts in three Local Health Districts in NSW from 2006 to 2023, representing all equine Hendra virus events in NSW to date. Data was extracted from the NSW Notifiable Conditions Information Management System. Results: A total of 26 equine Hendra events occurred, with 134 human contacts. NSW equine Hendra virus events and associated human contacts predominantly occurred in winter and spring, in part, driven by seasonal variation in flying fox ecology. Human contacts most often reported being owners of the horse or owner's family members, including the majority (n = 15 of 18, 83 %) of higher-risk contacts. Higher-risk contacts often did not use personal protective equipment (n = 15 of 18, 83 %). No human contacts developed Hendra virus infection during the study period. Conclusions: Higher-risk human contacts often occurred with limited or no use of personal protective equipment, often in the context of stress and grief for the ill or dead horse, and contrary to biosecurity advice. This study highlights the importance of a One Health approach to understand Hendra virus spillover infection risks in horses and humans and design appropriate, effective prevention measures that address these human behaviors.