[Question #7781] Trichomonas Vaginalis

1 months ago
Hello Dr,

I am a 42 year old married female, currently living in Southeast Asia, where I’m finding it hard to get conclusions to my questions. 

Results from a recent smear test (part of an annual medical) showed that I had trichomonas vaginalis which shocked me as I’ve only ever had sex with my husband of 22 years. He maintains he’s never been with anyone else, got checked straight away and said he was clear. I believe him but, of course anything is possible. 

I visited a gynaecologist here to ask questions and get treatment. On my first visit she said it was possible I got this from a public toilet seat. I had already read online (NHS - I’m British) that this was not possible, or at least extremely unlikely.  I actually asked her to delay treatment for a few days to take another test.

Second test show I now don’t have it, but she maintains the trich went away on its own, because I’m healthy and because my recent period ‘washed it away’.

This doesn’t sound right  to me (and not in line with anything I’ve read). I asked her if it was possible the original smear test was just wrong, which she simply wouldn’t answer (perhaps because it was all done within  the same clinic). 

I’m not looking to lay any blame at her door and I suspect things have got lost in translation.  I just want to get answers for myself:

1) is this something you can get from a toilet seat or is it strictly from sexual contact, as I’ve read? 
2) if I had it, could it have been ‘washed away’ by my period or just miraculously disappeared?

I will undergo another test when I get back to the U.K., though in the current climate I’m not sure when that will be. In the meantime, any advice you have  would help me allay my fears/confusion/frustration.

Many thanks. 


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
1 months ago
Welcome to the forum. Thanks for your confidence in our services. Your case raises issues that will benefit other forum users -- so I'm taking the opporunity, as I sometimes do, for a more extended blog-like reply for future use. Sorry if it's more than you were hoping for, but please bear with me!

I'm sorry you've found one or more doctors who either don't understand trichomonas -- or who might be trying to soften the message about sexual transmission (the toilet seat comment). Altough I have little direct experience in SE Asia, I believe there may be cultural trends there that minimize providers' frankness about sexual transmission, perhaps especially for women in their care.

Here are some basic facts about trich which should start to help. Until ~40 years ago, there was uncertainty about sexual transmisison. That's because chronic infection is extrmeely common -- Trichomonas vaginalis can be carried in the vagina for years without symptoms, undetected by standard lab tests (until better testing was developed in the last decade). It could then cause symptoms years later, or might be diagnosed when something else caused vaginal discharge or otherwise resulted in testing. As a result, many or most cases in women occurred in settings that didn't seem to support sexual transmisison -- married and monogamous, not sexually active for several years, and so on. And infected women's male partners rarely had symptoms and tested negative, even though infected. Pretty easy to see how the pattern overall, and cases in individual women, didn't fit sexual transmission in ways obvious for infections like gonorrhea or syphilis.

As for toilet seats and STDs, that's always been a canard -- it simply doesn't happen, for any STD. As implied above, such assumptions and even medical advice evolved as face-saving explanations for infected persons, their unfaithful partners, or both; or as an easier explanation for doctors uncomfortable with their patients' sexuality.

That you tested positive and then negative is hard to interpret without knowing exactly what types of test were done each time. Modern, accurate testing depends on detecting the DNA of Trichomonas vaginalis by a PCR test. Until the last 10-15 years, most testing depended either on seeing the organisms by microscopy of vaginal fluid, by pap smear, or by culture -- all of which miss at least half of all infections. In addition, these all commonly give falsely positive results.

Putting all this together, along with the apparent absence of recent STD risk for you or your husband, one of two scenarios is likely. First, that your initial positive test used one of the older methods, was false, and the follow-up negative test was by PCR. If so, it is very unlikely you have it. Second, you do have it, your first test was accurate (either PCR or one of the older tests), and the second test -- probably NOT a PCR test -- missed it. The first scenario probably is more likely. (Of course, the third possibilty -- which you mention indirectly -- is that you did acquire trich recently, and that your husband has been unfaithful. Even PCR can miss some infections in men, who rarely have symptoms from trichomonas. Of course I cannot judge this, but it sounds like you're pretty confident about him.)

If you're returning to UK soon, it's OK to wait and then assure that both you and your husband have accurate (PCR) testing, then decide about treatment. But if return isn't imminent, the smart thing is for both you and your husband to be treated. All things considered, it may be unnecessary, but treatment is easy and effective. (However, it must be with 5-7 days of metronidazole or tinidazole:  the formally recommended single-dose regimens are now known to be unreliable.) Another option might be to find a genuine STD expert wherever you are -- there are many fine providers and clinics in most major SE Asian cities like Bangkok, Hanoi, and Phnom Penh.

I hope this information is helpful. Let me know if anything isn't clear.

HHH, MD

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