Evidence of endemic Hendra virus infection in flying-foxes (Pteropus conspicillatus)--implications for disease risk management.
Authors: Breed Andrew C, Breed Martin F, Meers Joanne, Field Hume E
Journal: PloS one
Summary
# Hendra virus in flying-foxes: endemic circulation and management implications Hendra virus poses a significant zoonotic threat to equine and human populations in Australia, yet understanding its persistence in bat reservoirs remains critical for effective disease control. Breed and colleagues conducted a 25-month serological survey of spectacled flying-foxes near a 2004 outbreak site, analysing 521 individuals across six sampling sessions using virus neutralisation testing to detect antibody responses. Rather than the anticipated episodic infection pattern, seroprevalence increased gradually over two years, indicating endemic rather than sporadic viral circulation—a finding fundamentally reshaping how we understand henipavirus maintenance in bat populations. Pregnancy and lactation emerged as significant risk factors, with pregnant females showing substantially higher antibody titres than males, whilst seasonal fluctuations in antibody levels suggested periodic variations in population-level herd immunity. These observations have direct implications for disease risk management strategies: because endemic viruses require far smaller host populations to persist than acute, self-limiting pathogens, traditional epidemic models cannot reliably predict henipavirus dynamics, and practitioners should expect year-round transmission risk rather than discrete outbreak periods when formulating biosecurity protocols around bat habitats and equine premises in endemic regions.
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Practical Takeaways
- •Hendra virus appears to be endemic in flying-fox populations rather than episodically emerging, meaning equine disease risk may be persistent rather than sporadic—inform ongoing biosecurity planning
- •Seasonal fluctuations in bat herd immunity suggest heightened risk periods may correlate with breeding/pregnancy cycles—monitor timing of outbreaks relative to bat reproductive seasons
- •Risk management strategies must account for bat life history and population dynamics, not assume acute infection models—work with veterinarians to develop year-round rather than event-based prevention protocols
Key Findings
- •Seroprevalence of Hendra virus gradually increased over 25 months in flying-fox population, suggesting endemic rather than episodic infection pattern
- •Age, pregnancy, and lactation were significant risk factors for detectable neutralizing antibody response
- •Female flying-foxes showed significantly higher antibody titres than males, with highest titres in pregnant animals
- •Temporal variation in antibody titres suggests herd immunity may fluctuate seasonally, requiring smaller critical host population size to sustain virus transmission