[Question #3928] MSM unprotected oral sex - syphilis risk?

32 months ago
Dear Drs,

I am a 35-year-old gay male who lives in New Zealand. I am in a long-term relationship but on 25 June gave unprotected oral sex (and received protected anal) from a married man I met on a hookup site. He has since been in touch to tell me that he tested positive to syphilis. I didn't notice any obvious sores or rashes.

I am due to attend a local Sexual Health Clinic on Monday, where I assume that I will be provided with treatment. However, I have recently recalled a brief epsiode from perhaps 18 months ago, where I performed unprotected oral sex on a man I met in a cruising area; this only lasted about 60 seconds before I freaked out and left. I am unable to remember having any symptoms after this, and I cannot recall my partner having any symptoms either (despite my foolish actions I have a fair bit of health anxiety and feel I would remember chancres or itchy rashes if they were there).

My questions are:

- If I *did* test positive for syphilis on Monday, is it possible that they could tell me whether this was from the most recent encounter or from further back?
- Assuming I receive treatment on Monday, how long until I am non-transmissible?

Thank you in advance.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
32 months ago
Welcome to the forum. Thanks for your question.

It takes at least 2-3 weeks and sometimes 6 weeks for syphilis blood tests to turn positive. So if your test is positive, it will not be from the recent contact. Whether it would be from the one18 months ago, or even previous to that, might not be possible to determine. Either way, almost certainly the clinic will treat you with a single dose of long acting (benzathine) penicillin G (BPG). (That said, BPG is in short supply in many settings worldwide-- it's conceivable they're use a different treatment.) If your blood test is positive, indicating longstanding infection, you'll require 3 weekly dozes of BPG and probably a lumbar puncture (spinal tap) to assure you don't have asymptomatic infection of the central nervous system, generally the most dangerous form of syphilis. Also assuming you and your wife have been sexually active, in case of a positive test your wife will need to be informed and treated.

Newly acquired syphilis is not transmissible until the initial lesion (chancre) appears, usually 10-20 days after exposure, so your wife probably is not at risk. If your current test is negative and careful examination shows no evidence of new syphilis (which it probably will not), she will not need treatment. However, if in doubt, treatment sometimes is recommended -- the sexual health clinic will know how to deal with all this.

I'll be interested in hearing how things stand after you've been to the clinic. In the meantime, I hope these comments are helpful.

HHH, MD
---
32 months ago
Thanks Doctor. Is it possible to comment on the likelihood that I had been infected from the episode 18 months ago, given the lack of symptoms in that time? Not sure if it makes a difference but my partner is also male.
32 months ago
The reason I am focused on this encounter from 18 months ago is that my partner and I both underwent screening tests prior to that and were negative for all STIs.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
32 months ago
Quite a bit more info is needed to judge the likelihood you were infected 18 months ago. Presumably that exposure was confirmed, i.e. you know for sure that person had syphilis. But I also need to know the stage of his infection, if you know it (primary, secondary, latent, etc); whether or not you were treated; and if so, that follow-up testing was done to assure you were not infected (usually 6+ weeks after your treatment).---
32 months ago
Thanks Doctor. I was planning to provide information about the outcome of testing today but wanted to follow up on your comment below. The encounter from 18 months was status unknown. I didn’t notice any sores or rashes but I know symptoms are not always visible. I was never tested after that exposure. I hope that’s helpful information.
32 months ago
Quick update: although I'm still planning to attend the clinic this afternoon, I decided I would attend a drop-in centre this morning and undergo a 60-second rapid HIV and Syphilis blood test - I know this wouldn't pick up any recent infection but was hoping for peace of mind in relation to my sexual contact from 18 months ago. It came back negative for both HIV and Syphilis, which I was extremely relieved about. I will attend the clinic this afternoon for treatment following my recent exposure and can hopefully begin to put all of this behind me.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
32 months ago
These results say nothing about whether you were infected during your recent exposure, but they exonerate the event 18 months ago. Depending on the details of your recent partner's reported syphilis, it is likely the clinic will give preventive treatment with penicillin, as I said in my initial reply.

Normally threads are closed after two follow-up comments and replies, but I'm leaving this open for you to tell me the outcome of your clinic visit, should you wish to do so. If not, I'll close it within 24 hours.

---
32 months ago
Thank you for leaving this open Doctor. I went to the clinic visit and was given an oral check-up; I was told I didn't appear to have any sort of chancre in my mouth. I was then given an injection of penicillin (actually two; one in each buttock) and had my blood drawn. I'll know the results in a week but the doctor I saw said it seemed unlikely that I would test positive. 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
31 months ago
I agree with your doctor. See my further comments in your new thread.---