Hendra virus infection dynamics in Australian fruit bats

Area of Science:

• Veterinary Virology
• Zoonotic Disease Epidemiology
• Wildlife Health

Background:

• Hendra virus (HeV) is an emerging zoonotic pathogen in Australia, with pteropid fruit bats (flying foxes) as its wildlife reservoir.
• Spillover events from flying foxes to horses and humans have resulted in significant fatalities since 1994.
• Understanding HeV infection dynamics in the reservoir host is crucial for preventing transmission.

Purpose of the Study:

• To investigate the dynamics of Hendra virus infection and excretion in free-living flying foxes.
• To determine if urine is a viable route for HeV excretion from flying foxes.
• To assess temporal and geographical patterns of HeV shedding in flying fox populations.

Main Methods:

• A three-year longitudinal study (2008-2011) involving collection of pooled urine samples from roosting flying foxes.
• Screening of 1672 pooled urine samples using quantitative RT-PCR targeting the HeV matrix protein gene.
• Statistical analysis to identify associations between positive detections, year, and location.

Main Results:

• Hendra virus genome was detected in 25% of sampling events and 2.5% of pooled urine samples.
• Virus detection rates varied significantly by year and geographical location within Queensland.
• No detections were recorded in the Northern Territory, suggesting regional differences in HeV prevalence.

Conclusions:

• Hendra virus excretion by flying foxes is periodic and geographically variable, not continuous.
• Flying foxes can excrete HeV year-round, implying seasonal HeV incidents in horses and humans are influenced by factors beyond virus presence.
• Further research into these influencing factors is needed to enhance risk minimization strategies for HeV.