Trichomoniasis - Most Prevalent non Viral STI

New Research Into Trichomonas, the World's Most Prevalent Non-Viral STI

If someone asked you to name a sexually transmitted infection that is not transmitted virally, you’d probably find two names popping into your head: chlamydia and gonorrhoea. But though these two bacterial infections are alarmingly prevalent across the world, it’s actually trichomonas that tops the league tables when it comes to non-viral STIs.

Trichomonas – the STI you’ve never heard of – is a condition caused by the parasite Trichomonas vaginalis. According to the World Health Organisation it is the single most prevalent non-viral STI in the world, with 143 million new cases diagnosed every single year (by comparison, there are 131 million new cases of chlamydia, the next most common STI). That might seem like a scary number, but, according to the latest research, the medical community could be getting closer and closer to developing a vaccine. 

As reported here, a recent study found that one particular type of protein present in the membrane of T. vaginalis has a particular role to play in the binding of the parasite to the host cell it latches onto. The hope is that a vaccine may now be developed that specifically targets this protein, thus preventing the parasite from binding to host cells and causing an infection.

Until a vaccine does come along, trichomonas will continue to be treated with antibiotics. But in the interests of helping everyone avoid this (surprisingly widespread) STI, here’s a little more information.

What causes trichomonas?

As we've seen, trichomonas is caused by the parasite Trichomonas vaginalis. It is spread from person to person during unprotected sex, attaching to host cells that it then destroys and feeds on. In women, it most commonly infects the vagina and urethra; in men it infects the urethra and occasionally the head of the penis or the prostate. Unlike other STIs, it is very rare for T. vaginalis to infect other areas of the body such as the mouth or anus. 

You are most likely to catch trichomonas from unprotected vaginal sex, or the sharing of sex toys without washing them between uses. To avoid infection, always use a condom when you are not certain that your partner is STI-free.

What are the symptoms of trichomonas?

Around 50% of all people infected with trichomonas do not experience any symptoms. When symptoms do occur, they tend to be very similar to other STIs, such as chlamydia and gonorrhoea.

Symptoms in women include: 

  • Abnormal vaginal discharge, which may be yellow, green or smell fishy
  • Producing more vaginal discharge than usual
  • Swelling, itching and soreness around the vagina and the inner thighs
  • Pain when urinating
  • Pain during sex

Symptoms in men include:

  • Pain when urinating
  • Pain when ejaculating
  • Needing to urinate frequently
  • White discharge from the penis
  • Swelling, itching and soreness around the head of the penis

In some cases, trichomonas leads to complications when left untreated. Pregnant women who are infected are more likely to deliver prematurely and have a baby with a low birth weight. Having trichomonas also makes you more susceptible to contracting HIV, if you have unprotected sex with an HIV-positive person.

How is trichomonas diagnosed and treated?

Typically, trichomonas is diagnosed with a physical examination and a lab test. The physical exam checks for signs of inflammation and soreness around the genitals, and the test involves a swab of the penis or vagina to check for the presence of the T. vaginalis parasite. Men can also supply a urine sample.

If you don’t want to visit the doctor or you simply don’t have time, it is also perfectly safe to carry out a home test using a kit from a trusted service such as The STI Clinic. Click here to find out more about the home test kit The STI Clinic offers for trichomonas.

Once you have been diagnosed with trichomonas, you can begin treatment. The standard treatment for this infection is the antibiotic metronidazole, which is normally taken twice a day for a week. It’s also very important to notify any sexual partners, so that they can get tested and receive treatment as well.

Without antibiotic treatment, trichomonas is very unlikely to go away on its own. If you think you might have been infected with this STI, or any other, you should get tested as soon as possible.