Trichomonas vaginalis – An Overview of the Symptoms, Causes, and Treatment of the Most Common Sexually Transmitted Parasite

Trichomonas vaginalis is a protozoan parasite that causes a common sexually transmitted infection known as trichomoniasis. This infection primarily affects the female genital tract and is one of the most prevalent non-viral sexually transmitted infections worldwide.

Trichomoniasis, also referred to as trichomonas vaginitis, is characterized by a range of symptoms including vaginal itching, discharge, and irritation. In some cases, women may experience pain during urination or sexual intercourse. While men can also contract trichomoniasis, they often remain asymptomatic carriers and can unknowingly transmit the infection to their sexual partners.

Diagnosing trichomoniasis involves laboratory testing to detect the presence of the parasite in vaginal fluid or urine samples. Once diagnosed, treatment typically involves the use of antibiotics, such as metronidazole or tinidazole, to eliminate the infection. It is essential for both sexual partners to receive treatment simultaneously to prevent reinfection.

Preventing trichomoniasis involves practicing safe sex, which includes consistent and correct use of condoms. Abstaining from sexual activity is the most effective way to prevent trichomoniasis, but for those who are sexually active, regular testing and screening for sexually transmitted infections is crucial. Identifying and treating infections promptly can help prevent the spread of trichomoniasis and reduce the risk of complications.

What is Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted infection caused by a protozoan parasite. It is the most common non-viral sexually transmitted infection worldwide, affecting millions of people of all genders every year.

Trichomoniasis, also known as trichomoniasis vaginitis, primarily affects the female reproductive system, particularly the vagina and urethra. However, it can also infect males, although it is less common.

The parasite is transmitted through sexual intercourse, including vaginal, anal, and oral sex, as well as through the sharing of sex toys. It cannot survive outside the human body for long and is not transmitted through casual contact or by using public facilities, such as toilets or swimming pools.

Common symptoms of Trichomonas vaginalis infection include vaginal itching, discharge (which can be frothy, yellow-green, or gray in color), burning during urination, and discomfort during sex. However, many infected individuals may not experience any noticeable symptoms.

Trichomoniasis is easily diagnosed through laboratory testing, such as a vaginal swab or urine sample. Treatment typically involves medication, such as oral antibiotics, which can effectively kill the parasite and alleviate symptoms. It is also important for sexual partners to be treated simultaneously to prevent re-infection.

Preventing Trichomonas vaginalis infections involves practicing safe sex, including the use of condoms or dental dams, limiting sexual partners, and regular testing for sexually transmitted infections. Maintaining good genital hygiene can also help reduce the risk of infection.

If left untreated, Trichomonas vaginalis infections can lead to complications, such as pelvic inflammatory disease (in females), increased risk of acquiring other sexually transmitted infections, and adverse pregnancy outcomes.

Overall, understanding what Trichomonas vaginalis is and how it is transmitted is crucial for preventing and treating trichomoniasis and maintaining sexual health.

Causes of Trichomonas vaginalis

Trichomonas vaginalis is a parasitic protozoan that causes trichomoniasis, a common sexually transmitted infection. It is primarily transmitted through sexual contact, including vaginal, anal, or oral sex. The protozoan can be found in the vaginal fluid of infected individuals, and it can also survive for short periods of time on objects like towels or toilet seats.

Trichomoniasis is more common in women than men, with the infection causing vaginitis, inflammation of the vagina. Women who have multiple sexual partners or engage in unprotected sex are at a higher risk of contracting the infection. It is important to note that trichomoniasis can be present without any noticeable symptoms, making it easy to unknowingly transmit the infection to others.

It is recommended to use barrier methods of contraception, such as condoms, to reduce the risk of contracting or spreading trichomoniasis. Regular testing and prompt treatment of infected individuals can also help prevent the spread of the infection.

Symptoms of Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted infection caused by a parasite. It can lead to a condition known as trichomoniasis, which primarily affects the urogenital system.

One of the most common symptoms of trichomonas vaginalis is vaginitis or inflammation of the vagina. This often presents with symptoms such as itching, burning, and a foul-smelling vaginal discharge. The discharge can vary in color, ranging from yellow to green and may also be frothy in consistency.

In addition to vaginitis, individuals with trichomoniasis may experience discomfort or pain during sexual intercourse, as well as frequent urination or a burning sensation while urinating.

It is important to note that not everyone infected with trichomonas vaginalis will experience symptoms. In fact, it is estimated that up to 70% of infected individuals may be asymptomatic. However, even without symptoms, the infection can still be transmitted to sexual partners.

To confirm a diagnosis of trichomoniasis, a healthcare provider may perform a laboratory test to detect the presence of the parasite in a sample of vaginal fluid. If diagnosed with trichomoniasis, treatment with antibiotics is necessary to clear the infection.

Summary of symptoms:

• Vaginitis (inflammation of the vagina)
• Itching and burning
• Foul-smelling vaginal discharge
• Pain during sexual intercourse
• Frequent urination
• Burning sensation while urinating

How Trichomonas vaginalis is transmitted

Trichomoniasis, commonly known as vaginal trichomoniasis or trichomoniasis vaginitis, is a sexually transmitted infection caused by a protozoan parasite called Trichomonas vaginalis. The infection is generally transmitted from one person to another through sexual activity, including vaginal intercourse.

Trichomonas vaginalis can be easily spread from an infected individual who has symptoms or is asymptomatic, meaning they do not exhibit any symptoms. It is important to note that the infection can still be transmitted even if the individual does not present any visible symptoms.

During sexual activity, Trichomonas vaginalis can be passed between partners through the exchange of genital fluids. The parasite primarily infects the lower genital tract in women, including the vagina, cervix, urethra, and potentially the bladder. In men, the infection often affects the urethra. In rare cases, the parasite can also infect other parts of the reproductive system.

The risk of transmitting Trichomonas vaginalis can be reduced by practicing safe sex, using barrier methods such as condoms, and by being aware of the sexual health status of your partner. Regular screenings for sexually transmitted infections, including trichomoniasis, are recommended for individuals who are sexually active.

Key Points:
– Trichomoniasis is a sexually transmitted infection caused by Trichomonas vaginalis.
– The infection is transmitted through sexual activity.
– Trichomonas vaginalis can be passed between partners through the exchange of genital fluids.
– The infection primarily affects the lower genital tract in women and the urethra in men.
– Safe sex practices and regular screenings can help reduce the risk of transmission.

If you suspect you may have trichomoniasis or have been exposed to the infection, it is important to seek medical attention for diagnosis and treatment. A healthcare provider can conduct tests and provide appropriate medication to treat the infection.

Risk factors for Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted parasitic protozoan infection that causes symptoms of vaginitis in women. While anyone can be at risk of contracting Trichomonas vaginalis, certain factors may increase the likelihood of infection.

1. Multiple sexual partners

Having multiple sexual partners increases the risk of coming into contact with someone infected with Trichomonas vaginalis. The parasite is primarily transmitted through sexual intercourse.

2. Unprotected sex

Engaging in unprotected sex, such as not using condoms or other barrier methods, increases the risk of contracting Trichomonas vaginalis. The parasite can be passed from one person to another through vaginal, oral, or anal sex.

3. Previous infection

If you have previously had a Trichomonas vaginalis infection, you may be more susceptible to re-infection. The parasite can sometimes remain dormant in the body and cause recurrent infections.

4. Age and gender

Younger women, especially those between the ages of 14 and 24, tend to be at a higher risk of contracting Trichomonas vaginalis. Additionally, females are more likely to experience symptoms of infection compared to males, who often remain asymptomatic carriers.

5. Other sexually transmitted infections

Having another sexually transmitted infection, such as gonorrhea or chlamydia, increases the risk of also contracting Trichomonas vaginalis. These infections can weaken the immune system and make it easier for the parasite to establish an infection.

It is important to be aware of these risk factors and take preventative measures to reduce the risk of Trichomonas vaginalis infection. Using barrier methods during sexual intercourse, practicing safe sex, and getting regular check-ups can help protect against this parasitic infection.

Diagnosing Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted infection caused by a parasite. It is a common cause of vaginitis in women and urethritis in men.

Diagnosing trichomoniasis can be done through various methods, including:

Physical examination	A healthcare provider may perform a physical examination to check for symptoms such as inflammation, discharge, or ulcers in the genital area.
Microscopic examination	A sample of vaginal fluid or discharge is collected and examined under a microscope. The healthcare provider looks for the presence of Trichomonas vaginalis organisms.
Nucleic acid amplification tests (NAATs)	These tests detect the genetic material (DNA) of Trichomonas vaginalis. They are highly sensitive and specific.
Culture test	A culture test involves growing Trichomonas vaginalis in a laboratory setting. This method is less commonly used but can provide definitive diagnosis.
Point-of-care tests	These tests provide rapid results and can be performed at the point of care, such as a clinic or doctor’s office. They are simple to use and do not require laboratory equipment.

If diagnosed with Trichomonas vaginalis, it is important to seek treatment to prevent further transmission of the infection and reduce symptoms. Treatment usually involves prescribing antibiotics, such as metronidazole or tinidazole, to eradicate the parasite.

Complications of Trichomonas vaginalis

Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is a sexually transmitted infection that primarily affects the genitals. If left untreated, this infection can lead to a number of complications, including:

1. Increased Risk of HIV Transmission

Trichomoniasis has been found to increase the risk of transmission of the human immunodeficiency virus (HIV) during sexual intercourse. The inflammation and ulcerations caused by the infection can provide an entry point for the HIV virus, making it easier to contract and transmit.

2. Pelvic Inflammatory Disease (PID)

In women, untreated trichomoniasis can lead to pelvic inflammatory disease (PID). PID is a serious infection of the reproductive organs that can cause chronic pelvic pain, fertility problems, and complications during pregnancy. It occurs when the infection spreads to the uterus, fallopian tubes, or ovaries.

3. Preterm Birth

Pregnant women who have trichomoniasis are at an increased risk of delivering their baby prematurely. The infection can trigger inflammation and premature rupture of the membranes, leading to preterm labor and delivery. Preterm birth is associated with numerous health risks for the baby, including respiratory and developmental problems.

4. Increased Susceptibility to Other Infections

Trichomoniasis weakens the immune system in the genital area, making individuals more susceptible to other sexually transmitted infections (STIs) like gonorrhea, chlamydia, and herpes. Having multiple infections simultaneously can complicate treatment and increase the risk of long-term health consequences.

5. Impact on Sexual and Reproductive Health

Trichomoniasis can have a negative impact on a person’s sexual and reproductive health. The symptoms of trichomoniasis, such as itching, burning, and pain during intercourse, can lead to decreased sexual pleasure and discomfort. Additionally, the infection can cause recurrent episodes of vaginitis, which can disrupt overall reproductive health.

If you suspect you have trichomoniasis or have been diagnosed with the infection, it is important to seek prompt medical treatment to prevent these complications and reduce the risk of transmission to sexual partners.

Possible complications for pregnant women

Pregnant women who contract trichomoniasis, an infection caused by the protozoan parasite Trichomonas vaginalis, may experience several complications. Trichomoniasis can be transmitted during sexual intercourse and can lead to vaginitis, an inflammation of the vagina.

Untreated trichomoniasis in pregnant women can increase the risk of preterm labor and low birth weight. The infection may also lead to premature rupture of membranes, which can further increase the risk of preterm birth. Additionally, trichomoniasis can result in urinary tract infections and postpartum infections.

It is important for pregnant women to seek treatment for trichomoniasis if they experience any symptoms, such as itching, burning, or a foul-smelling vaginal discharge. Treatment typically involves the use of antibiotics that are safe for use during pregnancy, such as metronidazole or tinidazole.

To prevent trichomoniasis during pregnancy, it is important to practice safe sex and to be aware of the sexual history of partners. Using condoms consistently and getting regular screenings for sexually transmitted infections can help reduce the risk of contracting trichomoniasis or any other infection that could potentially harm the mother or baby during pregnancy.

Preventing Trichomonas vaginalis

Trichomonas vaginalis is a parasitic protozoan that causes trichomoniasis, a common sexually transmitted infection (STI) that affects the vaginal area. Fortunately, there are several steps you can take to reduce your risk of contracting or spreading this infection.

1. Practice safe sex: Using condoms consistently and correctly during sexual intercourse can greatly reduce the risk of trichomoniasis transmission. Condoms act as a barrier, preventing the exchange of bodily fluids and reducing the chances of infection.

2. Get tested: Regular screenings for STIs, including trichomoniasis, are essential for early detection and prompt treatment. If you or your partner have any symptoms or concerns, consult a healthcare professional and get tested.

3. Limit sexual partners: Having multiple sexual partners increases the risk of trichomoniasis and other STIs. Limiting sexual partners and practicing monogamy can significantly reduce the likelihood of infection.

4. Communicate with your partner: Open and honest communication with your sexual partner(s) is crucial. Discussing sexual health, getting tested together, and mutually agreeing on safe sex practices can help prevent trichomoniasis and promote a healthier sexual relationship.

5. Avoid douching: Douching alters the natural balance of bacteria in the vagina, increasing the risk of developing vaginal infections like vaginitis. It is best to avoid douching altogether as it can disrupt the vaginal environment and potentially make it more susceptible to trichomoniasis.

6. Practice good hygiene: Maintaining good hygiene in the genital area is important in preventing trichomoniasis. Regularly washing with mild soap and warm water, and drying the area thoroughly, can help reduce the growth and spread of the parasite.

7. Treat infected partners: If you or your partner are diagnosed with trichomoniasis, it is essential that both partners complete the prescribed treatment regimen to prevent reinfection or spreading the parasite to others. Follow your healthcare provider’s instructions and take all medication as directed.

By following these preventive measures, you can significantly reduce the risk of contracting trichomonas vaginalis or transmitting it to others. Remember, early detection, timely treatment, and consistent safe sex practices are key to maintaining sexual health.

Treatment for Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted protozoan parasite that causes trichomoniasis, a common infection in both men and women. It is important to seek treatment for trichomoniasis to alleviate symptoms and prevent the spread of the infection to others.

1. Medications

The primary treatment for trichomoniasis is the use of medications, typically oral antibiotics. The most common medication prescribed is metronidazole, which effectively kills the parasite and treats the infection. Other antibiotics, such as tinidazole, may also be prescribed depending on the severity of the infection and individual circumstances. It is important to complete the full course of medication as prescribed by the healthcare provider to ensure complete eradication of the parasite.

2. Partner Treatment

As trichomoniasis is a sexually transmitted infection, it is essential for both partners to receive treatment to prevent reinfection. Even if the partner does not display any symptoms, they may still carry the parasite and pass it on. It is important to inform and encourage sexual partners to seek medical attention and adhere to the prescribed treatment.

It is also advisable to abstain from sexual activity until both partners have completed treatment and have received confirmation of clearing the infection. This reduces the risk of re-infection and transmission to others.

It is important to note that some individuals may experience recurring trichomoniasis infections. In such cases, additional measures such as maintaining good hygiene practices, using condoms, and regular check-ups with healthcare providers may be recommended to prevent further infections.

Conclusion:

Trichomonas vaginalis is a sexually transmitted infection caused by a protozoan parasite. Prompt treatment is essential to relieve symptoms and prevent the spread of the infection. Medications, such as metronidazole, are commonly prescribed to kill the parasite. Partner treatment and practicing safe sex are essential to prevent reinfection and transmission. Consultation with healthcare providers and regular check-ups can help prevent recurring infections.

Medications for Trichomonas vaginalis

Trichomonas vaginalis is a protozoan parasite that causes a common sexually transmitted infection called trichomoniasis. It is important to seek treatment for trichomoniasis to prevent complications and reduce the risk of spreading the infection to sexual partners.

There are several medications available for the treatment of trichomonas vaginalis. The most commonly prescribed medication is metronidazole, which is available in oral and topical forms. Metronidazole works by inhibiting DNA synthesis in the parasite, effectively killing it.

Oral Medications

Oral metronidazole is the most commonly prescribed medication for trichomonas vaginalis. It is usually taken as a single dose or for a period of 5 to 7 days. It is important to complete the full course of treatment to ensure that the infection is completely eradicated.

Other oral medications that may be prescribed include tinidazole and secnidazole. These medications work in a similar way to metronidazole and are also taken as a single dose or for a period of several days.

Topical Medications

Topical metronidazole is available in the form of a gel or cream that is applied directly to the affected area. It is typically used in addition to oral medication to ensure complete eradication of the infection. Topical metronidazole should be applied as directed by a healthcare provider.

It is important to note that sexual partners should also be treated for trichomonas vaginalis to prevent reinfection. It is recommended to abstain from sexual activity until both partners have completed treatment and the infection has been fully cleared.

In addition to medication, practicing safe sex, such as using condoms, can help reduce the risk of trichomonas vaginalis and other sexually transmitted infections.

• Common medications for trichomonas vaginalis include:
• – Metronidazole
• – Tinidazole
• – Secnidazole

If you suspect you may have trichomoniasis or have been diagnosed with trichomonas vaginalis, it is important to seek medical treatment and follow the prescribed course of medication to effectively treat the infection and prevent further complications.

Treating partners of those infected

When one partner is diagnosed with trichomoniasis, it is essential that both partners receive treatment, even if the other partner is asymptomatic. Trichomoniasis is a sexually transmitted infection caused by the parasite Trichomonas vaginalis, and it can be easily transmitted between sexual partners.

If one partner is experiencing symptoms such as vaginal discharge, itching, or discomfort during sex, it is important to seek medical attention and get tested for trichomoniasis. A healthcare provider can diagnose the infection through a physical examination and laboratory tests.

Treatment for the infected partner

For individuals diagnosed with trichomoniasis, treatment usually involves a prescription medication, such as metronidazole or tinidazole. These medications are effective in eliminating the parasite and relieving symptoms.

It is important for the infected individual to complete the full course of medication as prescribed by their healthcare provider, even if the symptoms improve or disappear before finishing the treatment. This ensures that the infection is fully cleared from their system and reduces the risk of reinfection or transmission to a partner.

Treatment for the uninfected partner

Even if the uninfected partner does not have any symptoms, it is recommended for them to receive treatment as well. This is because trichomoniasis can be asymptomatic in some individuals, and they may unknowingly transmit the infection to others.

Both partners should refrain from sexual activity until they have completed their respective treatments and have been retested to confirm that the infection has been successfully cleared. It is crucial to practice safe sex, using barrier methods like condoms, even after the infection has been treated, to prevent reinfection or the transmission of other sexually transmitted infections.

In conclusion, when one partner is diagnosed with trichomoniasis, both partners should seek medical attention and receive treatment. This ensures that the infection is fully eradicated from both individuals and reduces the risk of reinfection or transmission to others.

Follow-up after treatment

Once the treatment for Trichomonas vaginalis, the sexually transmitted protozoan infection that causes trichomoniasis or vaginitis, is completed, it is important to follow up with a healthcare provider. This follow-up is necessary to ensure that the infection has been fully cleared and to monitor for any recurrence of symptoms.

During the follow-up visit, the healthcare provider may perform a physical examination and order laboratory tests to check for the presence of the parasite. It is important to note that even if symptoms have resolved, the parasite may still be present in the body. Therefore, laboratory testing is essential to confirm eradication of the infection.

If the tests come back negative, it is a good indication that the treatment has been successful and the infection has been cleared. However, if the tests come back positive, further treatment may be necessary to eliminate the parasite completely.

In addition to laboratory tests, the healthcare provider may also discuss safe sexual practices and offer advice on preventing future infections. It is important to practice safe sex and use barrier methods such as condoms to reduce the risk of transmitting or acquiring Trichomonas vaginalis or other sexually transmitted infections.

Conclusion

Follow-up after treatment for Trichomonas vaginalis is crucial to confirm the effectiveness of the treatment and ensure complete eradication of the parasite. It is important to adhere to the healthcare provider’s recommendations and continue practicing safe sex to prevent future infections.

Trichomonas vaginalis and other sexually transmitted infections

Trichomonas vaginalis is a sexually transmitted protozoan infection that affects both men and women. It is the most common non-viral sexually transmitted infection worldwide. Trichomoniasis is primarily transmitted through sexual contact, including vaginal, anal, and oral sex.

Trichomoniasis and Vaginitis

Trichomoniasis is often associated with vaginitis, which is an inflammation of the vagina. Symptoms of trichomoniasis include vaginal itching, burning, and irritation. In women, it can also cause a foamy, yellow-green discharge with a strong odor. Men may experience discomfort during urination or ejaculation.

Other Sexually Transmitted Infections

Trichomonas vaginalis is just one of the many sexually transmitted infections (STIs) that can be contracted through sexual contact. Other common STIs include chlamydia, gonorrhea, syphilis, and genital herpes. It is important to practice safe sex and get regular screenings for STIs to prevent transmission and ensure early detection and treatment.

Like trichomoniasis, these infections are caused by bacteria, viruses, or parasites and can result in various symptoms and complications if left untreated. The symptoms of these STIs may include genital sores, abnormal discharge, pain or discomfort, and in some cases, infertility or increased risk of HIV transmission.

The treatment for trichomoniasis and other STIs typically involves antibiotics or antiviral medications, depending on the nature of the infection. It is crucial to complete the full course of treatment to ensure complete eradication of the infection and reduce the risk of reinfection or complications.

Preventing the transmission of sexually transmitted infections requires practicing safe sex, including consistent and correct use of condoms, regular testing and screenings for STIs, and open communication with sexual partners about sexual health and history. Engaging in a monogamous relationship with an uninfected partner also reduces the risk of STI transmission.

If you suspect you may have contracted trichomoniasis or any other sexually transmitted infection, it is important to seek medical attention for diagnosis and appropriate treatment. Early detection and treatment play a crucial role in preventing the spread of these infections and protecting your sexual health.

Seeking medical advice for Trichomonas vaginalis

If you suspect you may have trichomoniasis, it is essential to seek medical advice as soon as possible. Trichomoniasis is a common sexually transmitted infection caused by the parasite Trichomonas vaginalis. This protozoan parasite mainly affects the female reproductive system, causing a condition known as vaginitis.

Visiting a healthcare provider is crucial for an accurate diagnosis and appropriate treatment. The symptoms of trichomoniasis can be similar to other vaginal infections, so a professional evaluation is necessary. During your appointment, your healthcare provider will likely ask about your medical history and perform a physical examination.

Importance of Diagnosis and Treatment

Diagnosing trichomoniasis involves conducting laboratory tests. A sample of vaginal discharge or urine can be collected and examined under a microscope for the presence of the parasite. Additionally, molecular tests may be performed to detect the genetic material of the parasite.

If you are diagnosed with trichomoniasis, your healthcare provider will prescribe appropriate treatment. Typically, trichomoniasis can be successfully treated with oral medication, such as metronidazole or tinidazole. It is crucial to complete the full course of treatment to ensure the infection is fully eliminated.

Prevention and Long-Term Outlook

To prevent trichomoniasis and other sexually transmitted infections, practicing safe sex is essential. Using condoms correctly and consistently can significantly reduce the risk of transmission. It is also advisable to limit the number of sexual partners and undergo regular screenings for STIs.

With early diagnosis and proper treatment, trichomoniasis can be cured effectively. However, if left untreated, the infection can lead to complications and an increased risk of other sexually transmitted infections. Seeking medical advice promptly and following the prescribed treatment can help prevent further health issues and promote overall well-being.

Q&A:

What is Trichomonas vaginalis?

Trichomonas vaginalis is a protozoan parasite that causes the sexually transmitted infection known as trichomoniasis. It primarily affects the urogenital tract in both males and females.

How is Trichomonas vaginalis transmitted?

Trichomonas vaginalis is primarily transmitted through sexual contact. It can be passed between partners during vaginal, anal, or oral sex. It can also be transmitted from a mother to her baby during childbirth.

What are the symptoms of Trichomonas vaginalis?

The symptoms of trichomoniasis in females may include vaginal itching, burning, redness, and a frothy or yellow-green vaginal discharge. Males with trichomoniasis may experience penile discharge, itching or irritation inside the penis, and painful urination.

How long does it take for Trichomonas vaginalis symptoms to appear?

The symptoms of trichomoniasis may appear within 5 to 28 days after exposure to the parasite. However, some individuals with the infection may not experience any symptoms at all.

How is Trichomonas vaginalis diagnosed and treated?

Trichomonas vaginalis can be diagnosed through a physical examination, laboratory tests, and microscopic examination of vaginal or urethral fluid. It can be treated with prescription medications, such as metronidazole or tinidazole, which kill the parasite and alleviate symptoms.

What is Trichomonas vaginalis?

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis, a sexually transmitted infection (STI).