There are conspiracies all over the internet for anything you can possibly name!
Lyme disease is an infection that's spread by Ixodes ticks (black-legged or deer ticks in the eastern United States, and western black-legged ticks in the west) that carry the bacterium Borrelia burgdorferi. These ticks acquire the bacteria from mice and then infect humans by biting them and passing the bacteria into a person's bloodstream. These ticks are smaller than dog ticks and harder to detect. Immature ticks, or nymphs, are about the size of a poppy seed; adult ticks are the size of a sesame seed.