The News Minute | October 21, 2014 | 9.00 PM IST On an average every month, three Ebola infected people might board an international flight from any of the three countries in West Africa experiencing the virus outbreak, found a study.The study highlights the role of exit screening in these three countries - Guinea, Liberia and Sierra Leone - in containing the spread of the deadly virus."The risk of international spread could increase significantly if the outbreak in West Africa persists and grows," said Kamran Khan from the St Michael's Hospital in Toronto, Canada.For this, the researchers analysed flight schedules and flight itineraries of passengers from 2013 to predict expected population movements out of Guinea, Liberia and Sierra Leone.They also used World Health Organization (WHO) Ebola virus surveillance data to model the expected number of exported Ebola virus infections.The analysis assumed no exit screening and took into consideration the current epidemic conditions and international flight restrictions to and from Guinea, Liberia and Sierra Leone.More than 60 percent of travellers in 2014 are expected to have final destinations in low or lower-middle income countries."Given that these countries have limited medical and public health resources, they may have difficulty quickly identifying and effectively responding to imported Ebola cases," Khan added.The findings also indicate that it is far more efficient and less disruptive to screen travellers for Ebola as they leave affected countries in West Africa rather than screen the same travellers as they arrive at other airports around the world.The research was published in the journal The Lancet.