Trichomoniasis is a common sexually transmitted infection caused by the protozoan parasite Trichomonas vaginalis. It is one of the most common curable STIs globally, with an estimated 156 million new cases occurring worldwide each year.
Quick answers
– Trichomoniasis is caused by the parasite Trichomonas vaginalis and is spread through sexual contact.
– It is one of the most common curable sexually transmitted infections globally.
– An estimated 156 million new cases occur worldwide every year.
– It is more common in women than men. About 70-85% of infected people are asymptomatic.
– In the United States, around 3.7 million people have the infection.
– Rates are higher among certain groups like African Americans and people with multiple sexual partners.
– Symptoms in women may include vaginal discharge, itching/irritation, and odor. Men often have no symptoms.
– It is diagnosed through microscopic examination, culture or nucleic acid amplification tests.
– It is treatable with prescription anti-parasitic medication like metronidazole or tinidazole.
Global prevalence
The World Health Organization (WHO) estimates that there are approximately 143 million new cases of trichomoniasis worldwide each year. This makes it the most common curable STI globally.
However, the true prevalence is difficult to determine as many cases go undiagnosed and unreported. This is because up to 70-85% of infected women and over 50% of infected men show no symptoms.
Based on available data, the WHO estimates that in 2008:
– There were 276.4 million prevalent cases of trichomoniasis among women aged 15-49 years worldwide.
– The highest rates occurred in Africa, where 11.5% of women were estimated to have the infection.
– In the Americas and Europe, estimated prevalence was 7.4% and 1.3% among women aged 15-49 years respectively.
– Among men, reported infection rates ranged from 0-17%.
More recent studies indicate that trichomoniasis remains highly prevalent globally. A review published in 2021 estimated that in 2016 there were about 156 million new cases among women and men aged 15-64 years worldwide.
Prevalence in the United States
In the United States, trichomoniasis is the most common curable STI. Recent estimates indicate:
– Around 3.7 million people in the U.S. are infected with trichomoniasis.
– 1.3 million new cases occur per year.
– Prevalence is around 1.3% among sexually active females aged 14-49 years.
– Approximately 7.4% of women and 1% of men attending sexual health clinics test positive.
However, these estimates likely underrepresent the true burden of disease. Many people with asymptomatic infections do not get tested.
Groups at highest risk in the U.S.
Trichomoniasis disproportionately affects certain groups in the U.S.:
– Women: At least twice as many women get infected as men. The vaginal environment makes women more susceptible.
– African Americans: Trichomoniasis is around 13 times more common in African Americans compared to whites. Poverty and limited healthcare access contribute to higher rates.
– Older adults: Prevalence increases with age, peaking between 35-50 years.
– People with multiple partners: Having new or concurrent partners increases infection risk.
– People with other STIs: Co-infection is common, especially with chlamydia or gonorrhea.
Symptoms
Many people with trichomoniasis do not develop any symptoms. When present, symptoms can manifest 5-28 days after infection.
Symptoms in women
Up to 85% of infected women are asymptomatic. When symptoms do occur they may include:
– Vaginal discharge: Thin or frothy yellow-green discharge with a fishy odor. This is the most common symptom.
– Vaginal itching, irritation, redness: The vagina and vulva may become inflamed and irritated.
– Pain or discomfort during sex and urination.
– Lower abdominal pain
Symptoms in men
At least 50% of infected men show no symptoms. Less common symptoms can include:
– Discharge from the penis
– Burning/itching inside the penis
– Pain during urination or ejaculation
Diagnosis
Trichomoniasis is often asymptomatic so testing is needed to confirm infection. Diagnostic methods include:
– Microscopic examination: Looking at vaginal/urethral discharge under a microscope to identify motile trichomonads. Sensitivity around 60-70%.
– Culture: Taking a vaginal swab and growing trichomonads in culture medium. Sensitivity around 65-95%.
– Nucleic acid amplification tests (NAATs): Detecting trichomonad DNA through PCR or transcription-mediated amplification. High sensitivity and specificity. Recommended for optimal detection in both men and women.
– Rapid point-of-care tests: Provide results within minutes at the point-of-care. Lower sensitivity than NAATs.
Screening for trichomoniasis is recommended for:
– People attending sexual health clinics
– Those with HIV, regardless of symptoms
– Pregnant women
Complications
In women, potential complications of trichomoniasis include:
– Vaginitis: Inflammation of the vagina characterized by discharge, itching, and pain. Can increase susceptibility to other STIs.
– Atrophic vaginitis: Thinning and inflammation of the vaginal walls after menopause. This can cause painful intercourse.
– Infertility, low birth weight, and preterm delivery: Vaginal inflammation may increase risks during pregnancy. Treating trich early in pregnancy can reduce complications.
– Pelvic inflammatory disease (PID): Infection may spread to the uterus, fallopian tubes and ovaries. Can cause chronic pelvic pain.
In men, uncommon complications include:
– Prostatitis: Inflammation of the prostate gland. May cause pelvic pain and discomfort.
– Epididymitis: Inflammation of the coiled tube at the back of the testicles. Leads to scrotal pain and swelling.
– Urethritis: Inflammation of the urethra causing burning, itching and discharge.
Treatment
Trichomoniasis is curable with prescription anti-parasitic medication:
Recommended first-line treatments:
– Metronidazole: Taken orally in a single 2g dose or 500mg twice daily for 7 days. Cure rates exceed 95% with single dose. Avoid alcohol during and for 3 days after treatment.
– Tinidazole: Single 2g oral dose. Fewer side effects than metronidazole and can be taken with alcohol, but more expensive.
Alternative regimens:
– Metronidazole: Extended 7-10 day course or 2g daily for 5 days.
– Tinidazole: 500mg twice daily for 5-7 days.
Sex partners should also be treated simultaneously to prevent reinfection. Patients should avoid sex until treatment is completed and symptoms resolve. Follow-up testing is recommended.
While medication treats infection, it does not provide immunity against future infection. Risk can be reduced by using condoms correctly and limiting sexual partners.
Prevention
Strategies to help prevent trichomoniasis include:
– Condoms: Correct and consistent use of condoms during sex decreases transmission risk. However, condoms do not fully protect against trich as it can be passed from skin-to-skin contact.
– Mutual monogamy: Being sexually active with only one uninfected partner lowers infection likelihood.
– Routine STI testing: Getting regularly tested allows early detection and treatment. Annual screening is recommended for sexually active women under 25 and older women at risk.
– Avoid douching: Vaginal douching alters vaginal flora and makes women more prone to infection.
– Personal hygiene: Proper genital hygiene may offer slight protective benefit, but is not a primary prevention method.
– Expedited partner therapy: Providing infected people with medications to give their partners facilitates simultaneous treatment and interruption of transmission.
Conclusion
In summary, key points about the prevalence of trichomoniasis include:
– Trichomoniasis is a very common curable STI globally, with 156 million new cases estimated per year.
– It disproportionately affects women, with prevalence highest in Africa. Men are often asymptomatic.
– In the U.S., around 3.7 million people have trichomoniasis. It is most common in African Americans and those with multiple partners.
– Many infections are symptomless. Discharge, itching and pain may occur. Diagnosis requires laboratory testing.
– It is readily cured with single dose antibiotics like metronidazole or tinidazole. Simultaneously treating partners prevents reinfection.
– Correct condom use, fewer partners, screening and partner management help control spread. But prevention remains challenging given asymptomatic carriage.
Ongoing awareness, testing and treatment are crucial public health interventions for controlling trichomoniasis transmission and reducing complications like infertility, adverse pregnancy outcomes and enhanced HIV susceptibility.