What is it?

Trichomonas, trichomoniasis, or trich (pronounced trick), is a contagious STI caused by a tiny parasite Trichomonas vaginalis (TV). Infecting the vagina and urethra in women, and the urethra and sometimes the prostate gland in men, it's passed on through unprotected sex, and in rare cases by sharing sex toys. It's more common in women than men, hence the name 'vaginalis', and used to be a well-known cause of vaginal discharge and intense vulval soreness, but it's now creeping into boys' bits, too.

It may not be as talked about, or indeed as serious as other STIs, but it's been knocking around for centuries; it was first discovered in the genital secretions of both men and women in the 1800s. The World Health Organisation now estimates that the rate of infection has far exceeded the 174 million cases diagnosed around 10 years ago. In certain Southeast Asian countries it has become twice as common as gonorrhoea, and five times as common as chlamydia and syphilis. In the UK there's an estimated 6000 new cases each year.  

What are the symptoms of trichomonas?

Like many other STIs, there may be no symptoms at all - especially in men - but for those who do they normally appear from three to 21 days after infection. Generally, the symptoms are much worse for women and can be similar to gonorrhoea. An unpleasant vaginal discharge is one of the first signs, followed by soreness, inflammation and itching in and around the vagina; pain when peeing; pain when having sex; and lower abdominal tenderness.

For men, there may be a discharge from the penis; pain or a burning sensation when peeing; and, on rare occasions, inflammation of the glans (head of penis) or foreskin.

What does the discharge look like?

In women this can be yellow or greenish, thin, frothy and have a musty or fishy smell. Nice. In men it's thin and whiteish.

How is trichomonas treated?

If you notice anything unusual 'downstairs' go to your nearest genitourinary medicine (GUM) clinic or make an appointment to see your doctor (GP). The GP may want to take a sample of the discharge and send it off to the lab for testing. Sometimes it can be picked up in a smear test in women. A lot of people infected with trichomonas are also found to have gonorrhoea as well, so the GP may test for this, too.

Treatment is simple and involves taking antibiotic tablets, usually Metronidazole, either as a single dose or a longer course (up to a week). To avoid re-infection, any sexual partners should also be treated.

What if I ignore it?

While a discharge from your bits doesn't do much for your sex appeal ignoring trichomonas doesn't pose any major health risks. In fact, in some cases the infection clears up by itself. However, it may take several weeks and there's no way of predicting whether it will clear or not.

There is a risk, however, of passing trichomoniasis onto your baby if you pick it up whilst you're pregnant. For men, it can cause prostatinitis (an infection of the prostate gland), but this is extremely rare.

How do I protect myself from contracting trichomonas?

As it's passed on through genital secretions using condoms offers good protection. If you're using sex toys always make sure you wash them in very hot soapy water afterwards or, better still, use a condom.

How soon can I have sex again?

Even if you do not have any symptoms you should hold off having sex until you've finished your treatment. It's an uncomplicated STI so it's not necessary to go back to the doctor for a follow-up appointment unless, of course, you think you may have caught it again.

Updated: 14/06/2011