Hendra virus infection dynamics in Australian fruit bats.
Authors: Field Hume, de Jong Carol, Melville Deb, Smith Craig, Smith Ina, Broos Alice, Kung Yu Hsin Nina, McLaughlin Amanda, Zeddeman Anne
Journal: PloS one
Summary
# Hendra Virus Shedding in Flying Foxes: Implications for Equine Risk Management Hendra virus remains a significant zoonotic threat in Australia, with repeated spillover events from its pteropid reservoir causing substantial mortality in horses and humans since 1994. Over three years, Hume and colleagues collected 1,672 pooled urine samples from 67 sampling occasions across Queensland flying fox colonies, using quantitative RT-PCR to detect viral genome shedding—a critical transmission route previously poorly understood. Whilst only 2.5% of samples tested positive overall, the detections occurred across 25% of sampling events, revealing that Hendra virus excretion is episodic rather than continuous, with notable geographical variation between Queensland populations and notably absent from surveyed Northern Territory colonies. Substantially important for equine practitioners, the finding that viral shedding occurs year-round contradicts the seasonal pattern of documented equine cases (70% occurring June–October), indicating that seasonal clustering reflects other epidemiological drivers—potentially host susceptibility, management practices, or environmental factors—rather than viral availability alone. This distinction fundamentally reshapes risk minimisation strategies; practitioners cannot rely on seasonal windows of reduced vigilance and must instead focus on identifying and managing those additional risk factors that determine whether viral exposure translates into equine infection.
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Practical Takeaways
- •Hendra virus can be shed by flying foxes year-round, so seasonal risk reduction alone is insufficient; focus risk management on other identified transmission factors
- •Geographic variation in virus prevalence exists across Australia, suggesting location-specific risk assessments are needed rather than blanket protocols
- •Horses and handlers should maintain heightened biosecurity awareness throughout the year, not just during traditional high-incidence months
Key Findings
- •Hendra virus genome detected in 2.5% of pooled urine samples and 25% of sampling events from free-living flying foxes over three years
- •Virus excretion occurs periodically rather than continuously across geographically disparate flying fox populations in Queensland
- •Seasonal clustering of Hendra virus incidents in horses (70% June-October) does not correlate with virus presence, suggesting other risk factors drive transmission timing