Yes, but they are single-host ectoparasites. They tend to land on, feed on, and finish their life cycle on one host. They aren't like ticks that will go from host to host. They also aren't generally found on other animals (rodents primarily) that act as a "resevoir" for Lyme and and other diseases. Lyme and other pathogens found in deer keds were likely picked up from the host deer, and since deer keds don't generally move from host to host they are highly unlikely to transmit it to humans. That means the ones you find on you likely haven't fed on a host yet that could have Lyme or other diseases. There seems to be no evidence they pass Lyme or other disease to humans.