Trichomoniasis is one of the most common sexually transmitted infections (STIs) in the world — and in Canada. It is caused by a tiny, microscopic parasite called Trichomonas vaginalis. Many people who have it do not even know, because symptoms can be mild or absent. However, it can still spread to partners. This article explains what trichomoniasis is, how it spreads, what symptoms to watch for, and how it is diagnosed and treated.
What Is Trichomoniasis?
Trichomoniasis is a parasitic infection, not a bacterial or viral one. The parasite responsible is a single-celled organism called Trichomonas vaginalis. It is sometimes called “trich” for short.
This infection is considered a sexually transmitted infection (STI) because it most commonly spreads through sexual contact. In Canada, STIs like trichomoniasis are tracked by public health agencies because they affect a large number of Canadians each year. According to the World Health Organization (WHO), trichomoniasis affects an estimated 156 million people globally each year.
The infection is most common in women between the ages of 16 and 35. However, anyone who is sexually active can get it — regardless of age or gender.
How Does Trichomoniasis Spread?
The main way trichomoniasis spreads is through sexual contact. This includes vaginal, anal, or oral sex with an infected partner. The parasite lives in the genital area and passes easily from one person to another.
However, sexual contact is not the only route. The parasite can survive outside the body for several hours on damp surfaces. For example, sharing towels, damp swimwear, or other personal items could carry a small risk of transmission. Warm, moist environments help the parasite survive longer.
In addition, the parasite thrives in alkaline conditions. This is one reason why the vaginal environment can be vulnerable, especially when its natural pH balance is disrupted.
It is important to know that a person can have trichomoniasis and show no symptoms at all. Even so, that person can still pass the infection on to a partner. This is why regular STI testing is important for sexually active Canadians.
Trichomoniasis Symptoms: What to Watch For
Symptoms of trichomoniasis can vary widely. Some people have no symptoms at all. Others experience significant discomfort. Symptoms often appear within 5 to 28 days of exposure, though they can show up later.
Symptoms in Women
Women tend to experience more noticeable symptoms than men. The infection typically causes a condition called vulvovaginitis — inflammation of the vulva and vagina. Common symptoms include:
A heavy vaginal discharge that is yellow-green in colour and has an unpleasant smell
Itching, burning, or redness around the vagina and vulva
Pain or discomfort during sex
A burning sensation when urinating
Frequent urination or the feeling of needing to urinate urgently
Sometimes the symptoms are mild. A woman may only notice light itching or slight discomfort during sex. Because these signs can seem minor, trichomoniasis is sometimes mistaken for a yeast infection or bacterial vaginosis.
Symptoms in Men
Men with trichomoniasis often have few or no symptoms. When symptoms do appear, they usually involve the urethra — the tube that carries urine out of the body. This is called urethritis.
Symptoms in men may include:
A thin discharge from the penis, especially in the morning
Redness or swelling at the tip of the penis
Irritation or itching inside the penis
Mild burning when urinating
Because symptoms in men are often very mild or absent, many men do not seek treatment. As a result, they may unknowingly continue to spread the infection. This makes partner testing and treatment very important.
How Is Trichomoniasis Diagnosed?
A doctor diagnoses trichomoniasis by identifying the parasite in bodily fluids. For women, this usually means a swab of vaginal discharge. For men, a swab of urethral discharge or a urine sample may be used.
The sample is examined under a microscope or sent to a laboratory for testing. Modern lab tests can detect the parasite quickly and accurately. According to the Mayo Clinic, a physical exam combined with lab testing is the most reliable way to confirm the infection.
Your family doctor or a sexual health clinic can perform this test. In Canada, many provincial health plans cover STI testing. Walk-in clinics also offer testing in most cities and towns. You do not need to feel embarrassed — healthcare providers deal with STI testing every day and are there to help.
Furthermore, because trichomoniasis is an STI, your doctor will likely recommend testing for other sexually transmitted infections at the same time. Infections like chlamydia, gonorrhoea, and HIV can sometimes occur alongside trichomoniasis.
Treatment for Trichomoniasis in Canada
The good news is that trichomoniasis is very treatable. Doctors use a class of antibiotics called imidazoles to clear the infection. The two most commonly prescribed medications are metronidazole and tinidazole.
Treatment options typically include:
A 7-day course: Taking a lower dose of the antibiotic twice daily for one week
A single-day treatment: Taking a higher dose all at once in a single day
Both approaches are effective. Your doctor will choose the best option based on your health and circumstances. These medications are generally available through a prescription from your family doctor, walk-in clinic, or sexual health centre.
Treating Your Partner
It is essential that your sexual partner is also treated — even if they have no symptoms at all. If only one partner receives treatment, re-infection can happen quickly. This is sometimes called a “ping-pong” infection.
Both partners should complete their treatment before resuming sexual activity. Using condoms during and after treatment adds an extra layer of protection.
Trichomoniasis and Pregnancy
Trichomoniasis during pregnancy requires careful management. Doctors generally avoid prescribing imidazole antibiotics during the first trimester (the first three months of pregnancy). If you are pregnant and suspect you have trichomoniasis, speak with your doctor or midwife right away. They will advise the safest treatment plan for you and your baby.
Untreated trichomoniasis in pregnancy has been linked to complications such as preterm birth. Therefore, early diagnosis and careful treatment are especially important.
How to Prevent Trichomoniasis
Preventing trichomoniasis follows the same principles as preventing other STIs. The most effective steps include:
Use condoms consistently: Use a condom correctly every time you have sex. Continue using condoms until both you and your partner have finished treatment and been cleared by a doctor.
Get tested regularly: If you are sexually active with new or multiple partners, regular STI testing is one of the best ways to protect your health.
Communicate with partners: Talk openly with sexual partners about STI testing and sexual health history.
Avoid sharing personal items: Do not share towels, swimwear, or other damp personal items.
Mutual monogamy: Being in a mutually monogamous relationship where both partners have been tested reduces risk significantly.
In Canada, free or low-cost condoms are often available through sexual health clinics, community health centres, and public health units. Many provinces also offer free or subsidised STI testing. Check with your provincial health authority for services available in your area.
For more information on sexual health and STI prevention, visit Health Canada’s sexual health resources.
When to See a Doctor
You should see a doctor if you notice any unusual discharge, itching, burning, or discomfort in your genital area. Even if your symptoms seem mild, it is worth getting checked. Mild symptoms do not mean the infection is less contagious.
You should also see a doctor if:
A sexual partner has been diagnosed with trichomoniasis or another STI
You are pregnant and concerned about an infection
Your symptoms do not improve after completing a course of treatment
You have recently had unprotected sex with a new partner
Your family doctor is a great first point of contact. If you do not have a family doctor, a walk-in clinic or a sexual health centre can help. Sexual health clinics offer confidential testing and treatment, and many operate on a drop-in basis across Canada. There is no need to feel embarrassed — your health and your partner’s health are what matter most.
Always consult a qualified healthcare provider before starting any treatment. Only a licensed doctor can diagnose trichomoniasis and recommend the right treatment for your situation.
Frequently Asked Questions About Trichomoniasis
Can you get trichomoniasis without having sex?
Trichomoniasis spreads mainly through sexual contact, but the parasite can survive on damp objects like towels for a few hours. Sharing personal items with an infected person carries a small but possible risk. However, sexual transmission remains by far the most common way trichomoniasis is passed from person to person.
How long does trichomoniasis last without treatment?
Trichomoniasis does not go away on its own without treatment. The infection can persist for months or even years if left untreated. During this time, a person remains contagious and can continue spreading trichomoniasis to sexual partners.
Is trichomoniasis the same as a yeast infection?
No, trichomoniasis and a yeast infection are different conditions. Trichomoniasis is caused by a parasite and is a sexually transmitted infection, while a yeast infection is caused by an overgrowth of fungus. Both can cause vaginal itching and discharge, which is why a proper diagnosis from a doctor is so important.
Can trichomoniasis come back after treatment?
Yes, trichomoniasis can come back, especially if a sexual partner is not treated at the same time. Re-infection is common when only one partner receives treatment. To prevent recurrence, both partners must complete treatment and avoid unprotected sex until they have both been cleared.
Is trichomoniasis dangerous if left untreated?
Untreated trichomoniasis can lead to complications, particularly in pregnant women, where it is linked to preterm birth and low birth weight. In addition, trichomoniasis can increase a person’s risk of getting or passing on HIV. Treating trichomoniasis promptly protects both your health and the health of your partners.
Does trichomoniasis always cause symptoms?
No, many people with trichomoniasis have no symptoms at all — especially men. However, a person without symptoms can still spread the infection to others. This is why regular STI testing is so important for sexually active Canadians, even when you feel completely healthy.
Key Takeaways
Trichomoniasis is a common, treatable sexually transmitted infection caused by the parasite Trichomonas vaginalis.
It spreads mainly through sexual contact, but can also survive briefly on shared personal items.
Many people — especially men — have no symptoms, yet can still pass the infection to others.
Women may experience yellow-green discharge, itching, burning, and pain during sex or urination.
Diagnosis requires a swab or sample test, available through your family doctor, walk-in clinic, or sexual health centre.
Treatment uses imidazole antibiotics and is highly effective. Both partners must be treated at the same time.
Use condoms during and after treatment to prevent re-infection.
Always speak with a healthcare provider for a proper diagnosis and treatment plan.
