At www.eurekalert.org/pub_releases/2019-03/ru-bmt032019.php … bacteria may travel thousands of miles through the air, globally. Press release from Rutgers University on a study published in the Philosophical Transactions of the Royal Society B – which shows that rather than bacteria hitching a ride on people and animals they are able to travel through the air (includes viruses). In this instance they are talking about bacteria with anti-biotic resistant genes. The study included scientists at the Russian Academy of Sciences and there were others from France, Chile, and Israel, If this theory is viable and has legs we may have a better idea on the transfer of viruses as in influenza epidemics which have been called bird flu. It may even explain the spread of bubonic plague in the 14th century AD – which was extremely rapid over a wide geographical region.