"the owner must have suffered a bout of syphilis "
syphilis
Public Domainsyphilis - Credit: Dr. David Cox

Syphilis is a sexually-transmitted disease caused by the spirochete bacterium Treponema pallidum.

The symptoms vary depending on the stage of development, but lesions are common. Usually, it takes 90 days for lesions to appear.

Unfortunately, there is still no vaccine.