[Question #5162] Trichomoniasis - Nonsexual Transmission

22 months ago
I’ve asked on here before. And the answer has been that trichomoniasis is rarely transmitted nonsexually. However, this article states otherwise. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031561/
If 24.7% of the girls who had never had sexual intercourse have it in that city. It’s got to be being transmitted in nonsexual ways (bathwater, etc.). Please explain this to me. Also, if I made out with (open-mouth kissed) a woman before being treated for trichomoniasis. Could I reinfect myself by open mouth kissing her and having intercourse with her 12 days after finishing the one big dose (4 pills) of Flagyl (metronidazole)? Thank you. 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
22 months ago
Welcome back to the forum, but I'm sorry you found it necessary. You seem to be quite obsessed with nonsexual transmission of STDs, previously HPV and now trichomonas.

It is well known that some cases of trichomoniasis cannot apparently be explained by sexual acquisition. Same for HPV. While we have probably at times forgotten to qualify our replies and use terms like "always" or "virtually always" sexually transmitted, the exceptions are known. But the large majority of cases are still sexually acquired, however. It is often difficult to know how to interpret claims of infected people that they have not had sex, or no sex with an infected partner. The incentive for some people to not give accurate sexual histories can be very strong.

The study you cite was conducted by competent, respected investigators, and I enjoyed reading it. But it is not conclusive. First, it is well known that sexually active women in many developing countries, especially young women, do not acknowledge sexual exposures or risk. Imagine the teen girl (in any culture) with strict parents who don't approve of non-marital sex. (In some cultures, there may be risk of being killed by parents or other family members). Or the young woman who doesn't admit being the victim of childhood sexual abuse. Interestingly, the study found that 4% of girls who claimed to be virgins had HSV2, incicating they must have had sex. I would criticize the investigators for eliminating only those girls from their subsequent analysis. It is unlikely that more than 10% of sexually active teens (in Nigeria or anywhere else) would have acquired HSV2. Therefore, the proportion who truly had sex undoubtedly is much higher than 4%; if I correctly understand the study numbers, half or more of women claiming to be virgins were not.

Even in we assume all the trich cases analyized had not been sexually exposed, the main risk factor found for trich was bathing. In that culture, this often means bathing in overtly polluted water -- i.e. with heavy contamination with human waste. I can easily imagine trichomonas being acquired in that manner. But that sort of risk rarely translates to the US and other industrialized countries. That a small proportion of trich is nonsexually acquired in settings of very poor hygiene says little about the risk of nonsexual transmission elsewhere.

Finally, as to your specific question, the study cited says absolutely nothing about the sort of exposure you are concerned about. Trichomonas is not known to ever infect or be carried in the oral cavity, and kissing and oral sex therefore are not known to be risk factors. As for the "having intercourse" part, of course you could have acquired trich from that 12 days fter taking metronidazole. What's the mystery in that? And how does this relate to nonsexual transmission?

You have signed into the forum with at least two usernames for the same email address, which is against forum rules. Please consolidate into a single account.

Repeat questions on the same topic -- in this case, nonsexual transmission of STDs -- are strongly discouraged. If continued, we begin not responding, i.e. deleting the question without reply (and without refund of the posting fee). Thanks for your understanding. But I do hope you find this reply helpful. My final advise is that you stop searching the internet on this topic. Anxious persons are always able to find evidence or support for whatever worries them. It isn't worth it and rarely helps real understanding.

HHH, MD
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22 months ago
Dr. HHH, thank you for answering. I’m sorry for the multiple account thing, I didn’t even realize I had done that honestly. What I’m referring to on the 12 days after is because I’ve read you are supposed to wait 7-10 days until you have sex after taking Flagyl for trich. As far as the oral sex thing, it seems that there is some risk. Please take a look at this information from the cdc and let me know why you say otherwise - https://www.cdc.gov/std/healthcomm/stdfact-stdriskandoralsex.htm. Also, I have read in medical Microbiology that, “Survival studies of T vaginalis in vaginal discharges have shown that these trophozoites can be cultured from toilet seats for 30 minutes or more.” Meyer EA. Other Intestinal Protozoa and Trichomonas Vaginalis. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Chapter 80.
I’m probably overthinking this, but is there any more recent studies about how long trich can survive on a toilet seat? I was thinking when I was using my toilet, I haven’t cleaned it since I’ve been treated 6 days ago. Is there anyway I could reinfect myself with it if I wasn’t discharging directly on the toilet seat? I doubt it could survive 6 days but I’m asking you. Thank you, and I know I’m an over thinker. But I can’t be living my life constantly thinking I’m going to transmit this to someone Nonsexually. Hard to function thinking that way. Thank you
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
22 months ago
It isn't necessary to wait 7-10 days before having sex after metronidazole. Perhaps you're confusing this with advice to women diagnosed with trich, who often are advised to wait a week to be sure symptoms clear up. That's because single dose metronidazole is only ~85% effective in women, i.e. 15% have persistent infection. However, in asymptomatic men treated presumptively because of diagnosis in a female partner, there's no need to wait.

Yes, you are overthinking it. Ability to detect trich on a toilet seat (or in moist towels or lots of other personal items) isn't the same as transmission risk. The same is true for HIV, gonorrhea, chlamydia, and herpes:  often can be detected on potentially contaminated surfaces. But that doesn't mean it's easy to catch it by contact with such surfaces. Contact with inanimate contaminated surfaces, clothing, etc has never been known to transmit any STD.

As I said in my opening statement above, you obviously are obsessed with nonsexual transmission of STDs, or at least these two (trich, HPV). Such thinking definitely is not normal, especially if you can't successfully shake the fear and stop worrying after the reasoned, science based reassurance you have had from me and Dr. Hook. If these thoughts continue, professional counseling probalby is in order. This is a form of germophobia, which can be an early sign of serious mental health disability. (For an excellent example where it can lead, see "The Aviator", the film biography of Howard Hughes. And a great movie, by the way, with Leonardo DiCaprio and Cate Blanchett.)
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