Disease has long been accompanied by suspicions of foreigners -- from Irish immigrants being targeted in the Typhoid Mary panic of 1900s America to Nepali peacekeepers being accused of bringing cholera to earthquake-struck Haiti in the last decade.
"It's a common phenomenon," said Rob Grenfell, director of health and biosecurity for Australia's science and research agency CSIRO.
"With outbreaks and epidemics along human history, we've always tried to vilify certain subsets of the population," he said, comparing the behaviour to 1300s plague-ridden medieval Europe, where foreigners and religious groups were often blamed.