Parasitic STIs

Overview

Trichomoniasis (Trich) is the most common non-viral STI. When symptomatic, it causes genital inflammation, itching, discomfort, or odorous discharge.

Prevalence

Trichomoniasis is the most common non-viral STI. It affects about 2.8 million people in the United States (CDC, 2022). It is more common in women than men.

Transmission

Trich spreads during penile-vaginal sex or vaginal-vaginal sex (CDC, 2022 & McCance and Huether 2019).It rarely spreads among men who have sex with men (MSM). Trichomonas can survive for very short periods of time outside the body — so spread through contact with contaminated objects such as sex toys is possible. It can also spread from mother to newborn during childbirth.

Symptoms

70-85% of people with trich have no symptoms. Symptoms in women include abnormal vaginal discharge (copious, odorous), discomfort with sex or urination, or genital itching or redness. Symptoms are often more prevalent during menses. Symptoms in men are rarer, and include mild itching, discharge, or discomfort with urination or ejaculation.

Complications

Trich is associated with a higher risk of cervical cancer, HIV, and pelvic inflammatory disease (PID). PID is an infection of the reproductive tract in women that can cause permanent damage and scarring — increasing the risk of infertility and ectopic pregnancy (pregnancy outside of the womb).

In pregnant women, it increases the risk of preterm birth, low birth weight, or premature rupture of membranes.

Diagnosis

Trich is diagnosed by cervical, vaginal, or penile swab, or by urine sample.

Treatment

Oral antibiotic medication is typically used to treat trich. Sexual partners should also be treated, even if they have no symptoms. The CDC recommends follow up testing 3 months after treatment, as reinfection is common.

Prevention

Consistent and correct use of condoms reduces the risk of acquiring STIs (such as trich) by about 60% (Crosby et al., 2012). Male circumcision also reduces the risk of acquiring trich.

Sex outside of a long-term faithful relationship increases the risk for acquiring sexually transmitted infections. Before engaging in sexual activity with a new partner, have an open and honest conversation about past STIs, and consider getting tested for STIs. Many STIs have no symptoms but have lasting consequences.

Overview

Pediculosis pubis (also known as “pubic lice” or “crabs”) are small (<1mm) crab appearing lice that infest the pubic hairs and other coarse hairs. They spread by intimate contact.

Diagnosis

An infestation is diagnosed by visualization of the crabs.

Treatment

Pubic lice is treated with over-the-counter or prescription medications, and nits (eggs) are removed with a fine tooth comb. Household contacts and sexual partners should also be treated, and all linens should be washed and dried on high heat cycles.

Overview

Scabies is caused by small mites which burrow beneath the surface of the skin and cause a pimple like rash and itching.

Diagnosis

Visualization of the rash and evidence of the mites is used to diagnose this infestation.

Treatment

It is treated with prescription topical or oral medication. Household contacts and sexual partners should also be treated and linens washed and dried with high heat.

Overview

Some intestinal infections, such as giardiasis or amebiasis, can spread sexually due to contact with fecal matter. This type of transmission is most common amongst men who have sex with men (MSM).

Symptoms

Symptoms include diarrhea, bloating, or nausea. Less commonly these infections can spread to other body organs, causing serious complications.