If my same-sex partner has trichomoniasis, can I catch it? #506/9

If my same sex partner has trichomoniasis, can I catch it?

Trichomoniasis is infectious for sure.  Use condoms or abstinence now until both of you have been treated (if you have been having intercourse).

·  Persistent viral infections, including the human papillomavirus, genital herpes, human immunodeficiency virus (HIV) and hepatitis B virus are common, as are Chlamydia trachomatis and trichomoniasis.



Reproductive Tract Infections, Including HIV and Other Sexually Transmitted Infections by

Contraceptive Choice

Choice of contraception directly affects the risk of RTI (Table 21-2). Condoms reduce the risks of both bacterial and viral RTIs; the evidence is strongest for condom effectiveness against HIV, trichomoniasis, genital herpes, and gonorrhea.  No recent data support spermicides’ ability to prevent bacterial or viral infections, including HIV.


CERVICITIS is a term used to refer to the syndrome of cervical inflammation that can accompany infection with some STI, notably Chlamydia trachomatis and Neisseria gonorrhoeae and occasionally trichomoniasis and genital herpes. It is defined as the presence of endocervical mucopurulent discharge, easily induced bleeding, and/or edematous ectopy. Cervicitis can have non-infectious causes, including chemical trauma, and may also be promoted by progesterone-based hormonal therapy or bacterial vaginosis.


TRICHOMONIASIS is caused by Trichomonas vaginalis, a motile protozoan with an undulating membrane and four flagella.

Prevalence. Trichomoniasis is the most common curable STI in the United States and worldwide. Each year an estimated 3 million U.S. women become infected.

Symptoms. Excessive, frothy, diffuse, yellow-green vaginal discharge is common, although clinical presentation varies from no signs or symptoms to erythema, edema, and pruritis of the external genitalia. Dysuria and dyspareunia are also frequent. The type of symptoms or signs alone does not distinguish the microbial etiology. Male sex partners may develop urethritis, balanitis, or cutaneous lesions on the penis; however, the majority of males infected with T. vaginalis are asymptomatic.

Diagnosis. Trichomoniasis is diagnosed when a vaginal culture or antigen test is positive for T. vaginalis OR typical motile trichomonads are identified in a saline wet mount of vaginal discharge. Examine vaginal secretions to verify the finding of trichomonads on a Pap smear, as this test is relatively non-specific for the diagnosis.

Treatment. Metronidazole 2.0 g orally at one time. Alternative regimens are metronidazole 500 mg orally twice daily for 7 days or tinidazole 2 g orally at one time. Most treatment failures are due to failure to treat the index patient’s sex partners; initial management should include retreatment of the patient and partners with single-dose metronidazole (2.0 g). Metronidazole-resistant T. vaginalis, although uncommon, can occur. Most treatment failures respond to higher doses of metronidazole therapy or to a single dose of tinidazole (2 g). Sex partners should be simultaneously treated with the same regimen as the index client.

Potential complications. Secondary excoriation may occur. Recurrent infections are common. Trichomoniasis has been associated with an increased risk of salpingitis, low birthweight, prematurity, and acquisition of HIV.

Behavioral messages to emphasize. Understand how to take or use prescribed medications. Return if the problem is not cured or recurs. Make sure sex partner(s) are treated. Use condoms to prevent future infections. Avoid drinking alcohol until 24 hours after completing metronidazole therapy.


URETHRITIS, INCLUDING NONGONOCOCCAL URETHRITIS (NGU) is caused by Chlamydia trachomatis about 30% of the time. Other sexually transmissible agents, which cause 10% to 45% of NGU, include Trichomonas vaginalis, Mycoplasma genitalium, and herpes simplex virus; Ureaplasma urealyticum may also contribute. The etiology of the remaining cases is unknown.


The above paragraphs come from the 19th edition of Contraceptive Technology


Jeanne M. Marrazzo, MD, MPH

Felicia Guest, MPH, CHES

Willard Cates, Jr., MD, MPH


This answer came almost entirely from the 19th edition of Contraceptive Technology, a book that describes how all the contraceptives work, the advantages and disadvantages of each and much more!  The chapters are by nationally recognized experts.


Click here to see how to order this important reference book and other important books for clinicians, counselors and women and men wanting the latest contraceptive information.



Her reply: “So, it is possible to catch trichomoniasis from your partner is same sex relationship?”


Yes, it is possible to catch it if one is referring to a same sex relationship (male/male or female/female).

Email received 5-29: “I have reviewed other question regarding trichomoniasis on your website.  I have one that’s just a little different.  A colleague diagnosed a client with trichomoniasis who stated she had not had sexual intercourse for 4-5 years. Needless to say, the client was very upset.  In reviewing the literature some articles state that trichomoniasis is sometimes transferred via wet towels, washcloths, bathing suits, underwear, toilet seats and vulva to vulva contact.  Is this correct?  Could trichomoniasis reside in someone at that time without symptoms or PID?  The Pap smear in 2007 did not identify trichomoniasis, but did indicate predominance of coccobacilla with shift in vaginal flora.”


“Thank you!”!


Here is what my understanding is:

  1. Women may be completely asymptomatic for a long time while harboring trichomonas.
  2. Men are usually asymptomatic with trichomoniasis.
  3. While trichomoniasis may be present on toilet seats, wet washcloths and towels, it is my understanding that transmission in this manner is not documented.
  4. Trichomoniasis may be transmitted from one woman to another in a number of ways.


Dr. Jeanne Marrazzo, could you please amplify on these comments?


Comments from Dr. Jeanne Marrazzo on 6-1: “Hi Bob, I think you are on target—the fomite issue has always been around because there are good data to show that trichomoniasis can survive for long periods in moist environments like bathing suits, towels, etc., but I am not aware of any substantive data to say that transmission from such sources has been documented.  I do believe it can live a long time in the Batholin’s and other periurethral glands, and we do see from time to time “re-emergence” when women really are adamant that they have not had recent sex.  Definitely well documented as to sexual transfer via vaginal fluid between women.  Hope this helps and you are well.”


Jeanne Marrazzo, MD, MPH

Associate Professor

Division of Allergy and Infectious Diseases

University of Washington

Harborview Medical Center

Seattle, WA



Key Words:  same-sex partner, trichomoniasis, infectious, condoms, intercourse, viral infections, HIV, Chlamydia, hepatitis B virus, genital herpes, cervicitis, syndrome, treatment, complications, risk, low brithweight, prematurity, Contraceptive Technology, advantages, disadvantages 



Marrazzo JM, Guest F, Cates W. Reproductive tract infections, including HIV and other sexually transmitted infections IN Hatcher RA, Trussell J, Nelson AL. et al Contraceptive Technology 19th edition; pages 503, 535, 552 and 553 

Posted 5-19-2009, Updated 5-28-2009, Updated 5-30-2009, Upated 6-6-2009


Posted on

June 17, 2009