Viruses and Bacteria (image) University of British Columbia Share Print E-Mail Caption Viruses and bacteria fall back to Earth via dust storms and precipitation. Saharan dust intrusions from North Africa and rains from the Atlantic. Credit (NASA Visible Earth) Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.