Brown dog tick (IMAGE) Experimental Biology Caption Since 2003, the vectoring capacity of the brown dog tick (shown under light microscopy) has spread across the American Southwest and parts of Mexico. Credit John VandenBrooks, Midwestern University Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. License CC BY-NC 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.