Many unknowns surround an 'unprecedented and worrying' hantavirus outbreak; WHO seeks to reassure public on pandemic risk The Andes strain, which can be transmitted between humans via droplets of saliva, was identified on Wednesday through sequencing in three patients who had traveled aboard the MV Hondius, a cruise ship that was due to dock in the Canary Islands in the coming days. Here is an overview of the main questions raised by this outbreak.