Ever imagined how an epidemic spreads so fast across continents in such a short period?  International travellers were considered the main carriers of bacteria, viruses or diseases and ended up in a witch hunt for those poor travellers.  Scientific analysis of these virus to ascertain the origin ended up in results which found these viruses were genetically similar to the virus which was reported in the original continent or country.

A new study has blown the cover off this issue.   virus swept up into the atmosphere on one continent and deposited on another.”  A research team of scientists from Canada, Spain and the U.S, have found that a remarkable amount of viruses are found in the atmosphere which can explain the spread of these viruses at the speed of the wind !  Viruses and bacteria are swept up in the atmosphere in small particles from soil-dust and sea spray.  To be precise these are carried over to the troposphere (the layer below stratosphere) where there is continuous air flow and less atmospheric resistance.

More details below.
Source: Viruses—Lots of Them—are Falling from the Sky

blogpost from: girishnair.com