I was recently diagnosed with first-stage syphilis on the basis of dark field microscopy and other symptoms. However, I have not had sex during the incubation period. While nonsexual syphilis is a theoretical possibility, most public health information suggests it is a practical impossibility. Therefore, wtf?

Does anyone have any experience with misdiagnoses? Any thoughts on what it could be assuming it is not syphilis? Finally, has anyone heard of genuine cases on nonsexual syphilis? Maybe I'm that 1 case in 100,000 or whatever, although that's obviously unlikely. Thanks in advance.