Ebola has so far only affected African countries and occasional cases outside of the continent have been rapidly contained. But the virus could mutate to spread more easily between people, making it more of a pandemic threat. A town square dedicated to Isaac Newton in Reston, Virginia seems like an unlikely place for an Ebola outbreak, but that’s exactly what happened around 30 years ago. In 1989, the Reston Primate Quarantine Unit looked after monkeys imported for scientific research and educational purposes. When dozens of macaques brought in from the Philippines suddenly died, testing seemed to show that they had died from the Zaire strain of the Ebola virus that can kill as many as nine out of ten people it infects. With homes and shopping centres very close to the ‘monkey house’, the army was called in to contain what had the potential to be a devastating public health outbreak. But one never came. Monkey handlers appeared to develop antibodies and did not get sick. That’s when scientists realised they had discovered a new strain of Ebola that they called Reston, that causes disease in animals but not people.