July 10, 2025
When it comes to sexually transmitted infections (STIs), most people immediately think of chlamydia, gonorrhea, or HIV. But there’s another extremely common, and often overlooked, parasite that affects millions worldwide: Trichomoniasis. Caused by Trichomonas vaginalis, this parasitic STI can lead to many problems, yet many people don’t even know they have it.
What makes trichomoniasis particularly tricky is that its symptoms can easily be mistaken for other infections like bacterial vaginosis, or in many cases, may not appear at all. Without proper diagnosis and treatment, it can increase the risk of serious reproductive health issues and the transmission of other STIs, including HIV.
In this blog, we’ll break down everything you need to know about trichomoniasis—from how it spreads and what symptoms to look for, to the best testing options, and treatments.
Trichomoniasis is a sexually transmitted infection (STI) caused by the parasitic protozoan Trichomonas vaginalis. It’s one of the most common non-viral STIs worldwide, infecting approximately 156 million people aged 15–49 each year. While it often affects adults, it can also impact newborns and increase vulnerability to other infections.
The culprit behind this condition is Trichomonas vaginalis, a single-celled, flagellated protozoan. Thriving in moist environments such as the genitals and urethra, this parasite feeds on epithelial cells and body fluids.
Transmission occurs almost exclusively through sexual contact; vaginal intercourse is the most common route. You can also get infected via genital-to-genital touch and, more rarely, through oral or anal contact. Pregnant women can pass the infection to their babies during childbirth, potentially leading to neonatal complications.
Symptoms typically start 5–28 days post-infection
Many cases go unnoticed for several reasons:
These factors result in missed diagnoses, ongoing transmission, and untreated health risks.
NAAT is the most accurate and reliable. For quick results, antigen tests are effective.
Home testing kits make diagnosis easier:
Yes—prompt antibiotic treatment plus partner treatment is essential. Metronidazole is highly effective.
A single dose of metronidazole or tinidazole under close medical supervision is the standard treatment, curing over 95% of infections. In cases of treatment failure, a 7-day metronidazole course is recommended, particularly in HIV-positive individuals.
To prevent reinfection, all sexual partners should be treated, even if symptomless. Abstain from sex until at least 7 days after treatment completion.
Yes—men can be reinfected if they resume sex with untreated partners.
Reinfection occurs in about 20% of individuals within three months, highlighting the need for follow-up testing and safer sex practices.
If left untreated, trichomoniasis can cause:
Consistent use of male or female condoms significantly reduces trichomoniasis transmission.
Limiting partners, mutual monogamy, and regular STI screening protect against reinfection and partner spread.
Women with symptoms of vaginitis and individuals at high risk (e.g., multiple partners, history of STIs, HIV-positive) should receive regular screening.
Aspect | Trichomoniasis | Bacterial Vaginosis (BV) |
Cause | Parasitic infection caused by Trichomonas vaginalis | Bacterial imbalance, often overgrowth of Gardnerella vaginalis |
Type of Infection | Sexually transmitted infection (STI) | Not classified as an STI (but more common in sexually active women) |
Transmission | Spread through vaginal, oral, or anal sex | Not spread through sexual contact but linked to sexual activity |
Symptoms | Genital itching, frothy yellow-green discharge, foul odor, burning urination | Thin gray/white discharge, strong fishy odor, mild or no irritation |
Common in | Both men and women (more symptoms in women) | Primarily affects women |
Asymptomatic Cases | Very common, especially in men | Also common, especially in mild cases |
Testing Methods | NAAT, Wet Mount, Antigen Detection, Culture | Vaginal swab, pH test, clue cell microscopy, amine test |
Itching/Irritation | Common | Rare |
Burning During Urination | Frequently reported | Occasionally |
Pain During Intercourse | Sometimes | Rarely |
Risk If Untreated | Infertility, PID, increased HIV risk, pregnancy complications | Increased STI risk, preterm birth, and miscarriage |
Partner Treatment Needed? | Yes, to prevent reinfection | No, usually not required |
Can You Have Both? | Yes, co-infection is common | Yes, often occurs with trichomoniasis or other STIs |
Trichomoniasis is a silent yet widespread public health issue that demands attention. Despite often mild or absent symptoms, genital itching, frothy discharge, and burning urination are red flags. With advanced diagnostic tools like NAAT and rapid antigen tests, we can detect and treat infections early, especially important given the rising asymptomatic cases.
Treatment is simple and effective with metronidazole but requires treating all sexual partners and abstaining until fully cured. Prevention through condom use, regular screening, and honest partner communication remains critical.
By enhancing awareness and adopting regular testing habits, we can better control this common yet underdiagnosed STI. If you’re experiencing symptoms or have had new or multiple partners, don’t wait get tested, treated, and protect your sexual health.