Ticks that Transmit Lyme are Small (image) DDC Caption The ticks which spread Lyme are typically no larger than a sesame seed (or the size of a period at the end of a sentence). It is thought that nymphs infect more humans than adult ticks because they are so hard to see. The tick's saliva contains an anesthetic like substance so you may not feel the bite. Find more information at www.bayarealyme.org Credit Bay Area Lyme Foundation Usage Restrictions None 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.