Trichomonas vaginalis is a small parasite that causes infection of the urinary tract and the genitals. It is generally passed on through sexual contact with an infected person.

The incubation period can be anything between 4 to 20 days, the average is a week. However, some people can be symptom- free carriers of the disease for years.

Between 10 and 50% of women infected with Trichomonas vaginalis do not show any symptoms. Those that do show symptoms may have:

• greenish-yellow foamy vaginal discharge with a very unpleasant odour
• itching in the vagina and vulva
• pain when passing urine
• pain when having sexual intercourse
• abdominal discomfort.

In males, 15 to 50% of infected individuals do not show any symptoms. Symptoms seen are very similar to urethritis and can include:

• discharge from the penis
• pain when passing urine
• the need to pass urine more frequently.

The recommended treatment is with an antibiotic called metronidazole. This is usually a very effective treatment in eradicating the disease.

Further guidance on the management and treatment of Trichomonas vaginalis includes:

• National guideline on the management of Trichomonas vaginalis by the British Association of Sexual Health and HIV.
• Trichomoniasis by PRODIGY guidance.

All current and previous sexual partners should be tested and treated to avoid reinfection.

The Department of Health has published a toolkit for assessing the range of competencies in skills, knowledge and attitudes required to manage sexually transmitted infections when delivering more specialised sexual health services within primary care. Click here for more information.

Infected individuals should avoid sexual contact until the infection has been successfully treated.

Not a notifiable disease. Refer to your local policy/infection control team for further information.

In males, rare complications include infection of the end of the penis, the prostrate gland or the epididymis.

If women are infected with Trichomonas vaginalis during pregnancy, it can lead to premature delivery and a baby of low birth weight.

The disease can be prevented by the regular and careful use of a condom.

No vaccine available.

Certain individuals may experience side-effects when taking the antibiotic metronidazole. These side-effects include:

• nausea
• vomiting
• a metallic taste in the mouth.

It is important not to drink alcohol whilst taking the metronidazole treatment and for 48 hours after stopping treatment, as alcohol interacts with the drug and can cause vomiting and other problems.

British Association for Sexual Health and HIV
www.bashh.org

NHS Direct
www.nhsdirect.nhs.uk

NHS Direct Wales
www.nhsdirect.wales.nhs.uk

BBC Health
www.bbc.co.uk/health

Young People’s Sexual Health website run by Central Suffolk NHS Trust
www.ypsh.net

TheSite run by YouthNet UK with advice and support for young adults
www.thesite.org

Playing Safely
www.playingsafely.co.uk

NAM, Aidsmap (Aids information for patients and health professionals)
www.aidsmap.com

Brook Advisory Centre
www.brook.org.uk

Sexual Health InfoCenter
www.sexhealth.org

Society of Sexual Health Advisers
www.ssha.info

Family Planning Association
www.fpa.org.uk

PRODIGY guidance
www.prodigy.nhs.uk

Information for young people on sexual health and life
www.likeitis.org

CHIN J, ed (2000) Control of communicable diseases manual. 17th ed. Washington: American Public Health Association.

PRODIGY (2002) PRODIGY guidance – Trichomoniasis [on-line]. London: Department of Health.
Available at: www.prodigy.nhs.uk/guidance.asp? [Accessed 15 April 2005].

SHERRARD J (2001) National guideline on the management of Trichomonas vaginalis. Clinical Effectiveness Group [on-line]. London: British Association of Sexual Health and HIV.
Available at: www.bashh.org/guidelines/2002/tv_0601.pdf [Accessed 16 April 2005].