Trichomonas vaginalis is the name given to the parasite which causes the sexually transmitted infection called trichomoniasis. The parasite lives in semen and vaginal fluid and can be spread through vaginal, anal or oral sex. In both men and women the symptoms of this infection can be unpleasant and will cause pain when urinating and unusual discharge, however, the symptoms vary between men and women. Many men and women do not experience any symptoms and the infection will go undetected which increases the risk of spreading it to other people.
Regular STI tests can identify trichomoniasis even if the symptoms aren’t present. Once diagnosed, the most appropriate treatment will be given to clear the infection which is usually antibiotics.
“Like all STIs the symptoms are not always noticeable, and this is the case with trichomonas vaginalis. Some people may be infected for months and will not show any symptoms, and in the meantime they’ve likely passed it on to others if they’ve had unprotected sex. Wearing a condom every time you have sex will protect you against all STIs and give you peace of mind. However, regular testing is also advised as this is the only way of detecting the parasite that causes trichomonias”
What is trichomonas vaginalis?
Trichomonas vaginalis is a tiny parasite which causes a sexually transmitted infection known as trichomoniasis. It is not a common STI but is still tested for as you can contract any sexually transmitted infection through unprotected sex.
Trichomoniasis can be difficult to diagnose as the symptoms are similar to other STIs. As with any STI, symptoms won’t always show and men in particular will rarely experience any symptoms. The vagina, urethra and foreskin of the penis can all be infected by the parasite and the symptoms are different in both men and women.
In women the symptoms consist of:
- Unusual vaginal discharge which is usually thick, thin or frothy, yellow or green in colour
- Discharge that has an odour of fish
- Vagina will become sore, itchy and may swell
- Discomfort or pain when passing urine or having sex
In men the symptoms may be slightly different, these include:
- Pain when urinating or ejaculating
- Urinating more frequently than usual
- Discharge from the penis which is thin and white
- The head of the penis or the foreskin will become sore red and swollen
If symptoms occur they will usually develop one month after infection, however, up to half of men and women won’t experience any symptoms, and therefore trichomoniasis can only be discovered through testing.
What causes trichomoniasis?
The parasite, trichomonas vaginalis, which is passed from one person to another through sex is the cause of trichomoniasis. Having unprotected sex with multiple sexual partners causes the spread of trichomoniasis. If you’ve had trichomoniasis in the past you’re more likely to contract the infection again, as is the case if you’ve previously had other STIs. Trichomoniasis also increases your risk of developing other sexually transmitted infections such as HIV.
How is trichomoniasis treated?
Treatment is necessary if you have trichomoniasis as the infection will not clear on its own. Antibiotics are used to treat this condition by killing the parasite causing the STI. Metronidazole is the most commonly used antibiotic to treat trichomoniasis. These antibiotics react with alcohol so you should abstain from drinking alcohol for 48 hours after taking this medication. Drinking alcohol while taking metronidazole may make you feel ill and it’s important to always finish the course of antibiotics to ensure that the infection has fully cleared.
Until the infection has cleared you should avoid any sexual intercourse. Delaying treatment puts you at risk of further complications such as in pregnancy. Pregnant women may pass the infection to the baby through birth, and the baby may be born prematurely and have a low birth weight. The longer you leave getting tested and treated the more chance there is of you spreading the infection to other people. To avoid getting infected again, you and your partner should both be treated.
How is trichomoniasis diagnosed?
As the symptoms can go unnoticed, a trip to the sexual health clinic is needed to get an expert diagnosis. To identify trichomoniasis a physical examination will need to be carried out as well as a sample. For women there will be a visual examination of the outer vagina, and because this parasite can infect the cervix an internal examination may be required. Your doctor will also swab the cervix and vaginal fluid to test it. Urine samples or urethral swabs will be carried out on men. Samples will be looked at under a microscope to identify the parasite. The secretions may also be cultured so that the parasite grows and can be identified.
How to prevent catching trichomoniasis
To prevent being infected with the parasite you should practice safe sex. As the parasite lives in semen and vaginal fluid the way it is spread is through sexual intercourse, this can be vaginal, anal, or oral sex where protection is not used. Trichomoniasis can also be spread through sharing sex toys.
Using condoms each time you have sex and when using sex times will help prevent getting infected and spreading it to other people.
After finishing the treatment you should wait at least 7 days before you have sex as there may still be a chance of being re-infected or passing on the parasite to your partner.
Safe sex is the most effective way of protecting against all STIs.