Apparently the Bb (Borrelia burgdroferi) spirochete that causes Lyme disease is related to the syphilis spirochete.
Bb can be transmitted transplacentally, even with in vitro fertilization; I've seen eight children infected in this way. People from Asia who come to me with the classic Lyme rash have been infected by fleas and gnats."
Gregory Bach, D.O., presented a study on transmission via semen at the American Psychiatric Association meeting in November, 2000. He confirmed Bb DNA in semen using the PCR test (Polymerase Chain Reaction).
Dr. Bach calls Bb "a brother" to the syphilis spirochete because of their genetic similarities. For that reason, when he treats a Lyme patient in a relationship, he often treats the spouse; otherwise, he says, they can just pass the Bb back and forth, reinfecting each other.