That the lethal Hendra virus could jump from Australia’s flying foxes to its humans might seem like nothing more than bad luck, an unfortunate but inevitable consequence of contact with animals.

Instead, it seems that people are partly responsible for the outbreak. Flying foxes are vectors, but human alteration of their ecology may have changed how Hendra moves through the animals.

By making flying-fox populations sedentary, stressed and fragmented, development might have also made them prone to viral spikes. Hendra’s spread in people may be, in a sense, a man-made disaster.

“We’re now seeing more evidence that human-induced environmental changes may be driving this disease,” said Raina Plowright, a disease ecologist at Pennsylvania State University. “That’s something that’s been proposed many times, but few people have been able to show a mechanism. Here’s a mechanism.”

Plowright is the lead author of a study of the Hendra virus May 11 in Proceedings of the Royal Society B. In September 1994, the virus killed 14 horses and their trainer in a suburb of Brisbane.

Thirteen more outbreaks have occurred since then, each involving transmission from a flying fox to a horse; of those, five resulted in transmission from horse to human. Fortunately, Hendra doesn’t seem to spread between people, but it’s still scary enough to merit Biosafety level 4 treatment. When researchers study it, they do so wearing moon suits, in high-security labs sealed with multiple airlocks. (read more)