Zika Transmission (IMAGE) La Jolla Institute for Immunology Caption Although Zika is primarily thought of as mosquito-borne illness, sexual transmission plays an important role in the spread of the virus. Weeks or even months after the virus has been cleared from the bloodstream, Zika can still be found in semen and transmitted through sexual contact. Women can pass the virus to their unborn babies during pregnancy. Credit Image: Dr. Kenneth Kim and Dr. Gina Kirchweger, La Jolla Institute for Allergy and Immunology Usage Restrictions None License Licensed content 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.