Genitourinary System Diseases

Fungal and Protozoan Reproductive System Diseases

Fungal Reproductive System Diseases

Inflammation of the vaginal mucosa is most commonly caused by a native yeast, Candida albicans, of the vaginal microflora that opportunistically grows in excess when other native flora are disrupted.
Vaginitis is inflammation of the vaginal mucous membranes that can occur during infection. The result is a painful, itching sensation and production of discharge, a combination of mucus, liquid, bacterial cells, and human cells. Vaginal discharge is naturally secreted by the mucous membranes of the vagina in healthy people. Inflammation increases the volume of vaginal discharge produced, and the discharge can be fermented by bacteria or fungi during infection, generating a characteristic fishy odor. Vaginitis is most commonly caused by Candida albicans, a species of yeast that can infect the mucous membranes of the mouth, throat, and vagina. Other symptoms of a yeast infection include vaginal discharge, vaginal itching, vaginal inflammation, and vulval inflammation. Fungal vaginitis is usually self-diagnosed and can be treated with topical over-the-counter antifungal drugs called azoles.
Candida albicans is a yeast native to the mouth, alimentary canal, and vagina. C. albicans may become overgrown causing candidiasis in the digestive system and vaginitis yeast infections in the vagina.
Credit: CDC/Dr. Brinkman

Protozoan Sexually Transmitted Diseases

The protozoan Trichomonas vaginalis is spread through sexual contact and can cause vaginitis in women and urethritis in men.

Trichomoniasis, a common STD, is caused by an infection with a protozoan, unicellular protist called Trichomonas vaginalis. The parasite is often a benign resident of the vaginal microbiota that spreads during sex. When the normal microflora of the vagina is disrupted, Trichomonas vaginalis can opportunistically spread.

Some T. vaginalis strains are more virulent than others, possessing virulence factors that aid in movement, adhesion, and spread in the reproductive system. They infect the vulva, vagina, cervix, or urethra in women and urethra in men. It usually does not infect other body parts such as the anus, mouth, or hands. Only 30% of people who are infected show any symptoms of the infection. Symptoms for women are genital itching, burning or redness, pain during urination, and abnormal vaginal discharge. For men, itching or irritation inside the penis, burning after ejaculation or urination, inflammation, and discharge from the penis are all symptoms of trichomoniasis.

Diagnosis is made by testing a sample of discharge from the patient—vaginal fluid for women and urine for men—for the presence of T. vaginalis DNA. Using condoms lowers the risk of getting trichomoniasis but does not completely eliminate it since trichomoniasis can infect areas not covered by condoms. Trichomoniasis can be treated with the oral antibiotics metronidazole or tinidazole.