Horse (image) University of Veterinary Medicine -- Vienna Share Print E-Mail Caption Bornaviruses cause a lethal disease in horses, the Borna disease. The pathogens are transmitted by screws. Credit Michael Bernkopf/Vetmeduni Vienna 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.