Can Lyme disease be transmitted sexually?

There is no scientific evidence that Lyme disease is transmitted sexually. Experiments with animals have repeatedly failed to transmit disease in this way. Although the bacteria have been found in vaginal secretions and in semen, it is a big step from that to causing infection.

The most likely explanation of partners, or several members of the same family having Lyme disease is that they go to the same places and are likely to have been bitten by ticks which have fed on the same mouse population.

Reference

National Institute for Health and Care Excellence Lyme Disease: Diagnosis and Management [M] Evidence Review for Person-to-Person Transmission NICE Guideline 95 April 2018