If I have an STI in one part of my body, can I spread it to someone using a different part of my body?

What I mean by this is: let’s say I am infected with oral gonorrhea. If I then have insertive vaginal sex with someone, can I spread my oral gonorrhea to them with my penis?

Similarly, let’s say I have I have a anal syphilis sore from receptive anal sex. If I have insertive anal sex with someone, could I infect them with my penis even though my infection is anal? 

I hope that makes sense, thank you for your help with this and all the other work you do!

The brief reply is no:  STDs localized to a particular anatomic site can only be transmitted from that site. However, you should be aware that many people who only have obvious infection at one site may actually be infected elsewhere. For example, if you had oral gonorrhea or chlamydia you might well also have urethral (penile) gonorrhea/chlamydia that hasn't caused obvious symptoms. In that situation, of course the infection could be transmitted from the urethra/penis.

However, the answer isn't quite as simple for syphilis, because syphilis is a systemic (body wide) STD. After a penile chancre has been present for a couple of weeks, the infection may have spread (without symptoms) to the mouth or anal area and be transmissible by oral or anal sex. This would be uncommon with syphilis under 2-3 months duration, but increasingly common thereafter -- but not impossible even within a month or two.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

HHH, MD