• Bacterial vaginosis
• Trichomoniasis
• Vaginal yeast infection

Some vaginal infections are transmitted through sexual contact, but others, such as yeast infections, probably are not.

BACTERIAL VAGINOSIS

Bacterial vaginosis (BV) is the most common cause of vaginitis symptoms among women of childbearing age. It previously was called nonspecific vaginitis or Gardnerella-associated vaginitis. Health experts are not sure what role sexual activity plays in BV.

BV reflects a change in the growth of vaginal bacteria. This chemical imbalance occurs when different types of bacteria outnumber the normal, “good” ones. Instead of Lactobacillus (a type of normal bacteria that can live naturally in the vagina) being the most numerous, increased numbers of bacteria such as Gardnerella vaginalis, Bacteroides, Mobiluncus, and Mycoplasma hominis are found in the vaginas of women with BV. Researchers are studying the role that each of these germs may play in causing BV, but they do not yet understand the role of sexual activity in developing BV. A change in sexual partners, using an IUD (intrauterine device), and douching may increase a woman’s risk of getting BV.

Symptoms

The main symptom of BV is an abnormal, foul-smelling vaginal discharge. Some women describe it as a fish-like odor that is most noticeable after having sex. Nearly half of the women with signs of BV, however, have no symptoms. A health care provider may see these signs while giving a physical examination and may confirm the diagnosis by doing lab tests of vaginal fluid.

Other symptoms may include

• Thin vaginal discharge, usually white or gray in color
• Pain during urination
• Itching around the vagina

Diagnosis

A health care provider can examine a sample of vaginal fluid under a microscope, either stained or in special lighting, to look for bacteria associated with BV. Then, they can diagnose BV based on

• Absence of lactobacilli
• Presence of numerous "clue cells" (cells from the vaginal lining that are coated with BV germs)
• Fishy odor
• Change from normal vaginal fluid

Treatment

Health care providers use antibiotics such as metronidazole or clindamycin to treat women with BV. Generally, male sex partners will not be treated.

Complications

In most cases, BV causes no complications. There have been documented risks of BV, however, such as an association between BV and pelvic inflammatory disease (PID). PID is a serious disease in women which can cause infertility and tubal (ectopic) pregnancy.

BV also can cause other problems such as premature delivery and low-birth-weight babies. Therefore, some health experts recommend that all pregnant women, whether or not they have symptoms, who previously have delivered a premature baby be checked for BV. A pregnant woman who has not delivered a premature baby should be treated if she has symptoms and laboratory evidence of BV.

BV also is associated with increased chances of getting gonorrhea or HIV infection. (HIV, human immunodeficiency virus, causes AIDS.)

TRICHOMONIASIS

Trichomoniasis (trick-oh-moe-nye-uh-sis) is one of the most common sexually transmitted infections (STIs). According to CDC, an estimated 7.4 million new cases occur in men and women every year in the United States.

Trichomoniasis is caused by a parasite called Trichomonas vaginalis. Trichomoniasis is primarily an infection of the urogenital tract. The vagina is the most common place for infection in women, and the urethra is the most common in men.

Symptoms

Trichomoniasis, like many other STIs, often occurs without any symptoms. Most infected men do not have symptoms. When women have symptoms, they usually appear within 5 to 28 days of exposure to the parasite.

Although some infected women have minor or no symptoms, many do have symptoms. The symptoms in women include

• Heavy, yellow-green or gray vaginal discharge
• Discomfort during sex
• Vaginal odor
• Painful urination

They may also have irritation and itching of the genital area and, on rare occasions, lower abdominal pain.

If present, the symptoms in men include a thin, whitish discharge from the penis and painful or difficult urination and ejaculation.

Diagnosis

A health care provider can diagnose trichomoniasis by performing laboratory tests on fluid samples from the vagina or penis. When women are infected with trichomoniasis, a pelvic examination reveals red sores on the cervix or inside the vagina.

Treatment

Because men can transmit the disease to their sex partners even when they don’t have symptoms, health experts recommend that both partners be treated to get rid of the parasite. Health care providers usually use metronidazole in a single dose to treat people infected with trichomoniasis. A person can get trichomoniasis again after being treated successfully, however.

Prevention

The surest way to avoid getting STIs is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected. Using a latex male condom consistently and correctly during sex may help prevent the spread of trichomoniasis.

Complications

Research has shown a link between trichomoniasis and two serious complications. Scientific studies suggest that trichomoniasis is associated with at least a 3- to 5-fold increased risk of HIV transmission and may cause a woman to deliver a low-birth-weight or premature infant. Scientists need to do additional research to fully explore these relationships.

VAGINAL YEAST INFECTION

Vaginal yeast infection, or vulvovaginal candidiasis, is a common cause of vaginal irritation. This common fungal infection occurs when there is an imbalance of the fungus called Candida albicans. Although this infection is not considered an STI, 12 to 15 percent of men develop symptoms after sexual contact with an infected partner.

Yeast are always present in the vagina in small numbers, and symptoms only appear with overgrowth. Health experts estimate that approximately 75 percent of all women will have at least one yeast infection with symptoms during their lifetimes.

Several factors are associated with increased yeast infection in women, including

• Being pregnant
• Having uncontrolled diabetes mellitus
• Using oral contraceptives or antibiotics

Other factors that may increase the incidence of yeast infection include using

• Douches
• Perfumed feminine hygiene sprays
• Topical antibiotics and steroid medicines

Health experts do not know whether yeast can be transmitted sexually. Because almost all women have the fungus in their vaginas, it has been difficult for researchers to study this aspect.

Symptoms

The most frequent symptoms of yeast infection in women are itching, burning, and irritation of the vagina. Painful urination and painful intercourse also are common.

Vaginal discharge is not always present and may be a small amount. The thick, whitish-gray discharge is typically described as cottage-cheese-like, although it can vary from watery to thick.
Most male partners of women with yeast infections do not have any symptoms of the infection. Some men, however, have reported temporary rashes and burning sensations of the penis after intercourse if they did not use condoms.

Diagnosis

Because few specific signs and symptoms are usually present, health care providers cannot diagnose this condition by a person’s medical history and physical examination. They usually diagnose yeast infection by examining vaginal secretions under a microscope for evidence of yeast.

Treatment

Various antifungal vaginal medicines are available to treat yeast infections. Women can buy antifungal creams to be applied directly to the area, tablets to be taken orally, or suppositories (butoconazole, miconazole, clotrimazole, and tioconazole) for use in the vagina. Because BV, trichomoniasis, and yeast infection are difficult to tell apart on the basis of symptoms alone, a woman with vaginal symptoms should see her health care provider for an accurate diagnosis before using these products.

Other products available over the counter contain antihistamines or topical anesthetics that only mask the symptoms and do not treat the infection.

Women who have chronic or recurring yeast infections may need to be treated with vaginal creams or oral medicines for long periods of time.

HIV-infected women may have severe yeast infections that often do not respond to treatment.

OTHER CAUSES OF VAGINITIS

Although most vaginal infections in women are due to bacterial vaginosis, trichomoniasis, or yeast, there may be other causes as well. These causes include allergic reactions, irritations, and other STIs.

Allergic symptoms can be caused by spermicides, vaginal hygiene products, detergents, and fabric softeners. Cervical inflammation from these products often is associated with abnormal vaginal discharge, but health care providers can tell them apart from true vaginal infections by doing lab tests.

RESEARCH

To control vaginitis, research is going on to find out the factors that promote the growth and disease-causing potential of vaginal microbes. This information could help improve efforts to treat and prevent vaginitis. No longer considered merely a harmless annoyance, vaginitis is the object of serious studies as scientists try to clarify its role in such conditions as PID and pregnancy-related complications.

NIAID-funded research has uncovered important information about yeast’s reproductive behavior, which could lead the way to new treatments for yeast infections.

NIAID-funded researchers discovered an association between lactobacilli and protection from BV. They then developed a lactobacillus vaginal suppository that help “good” bacteria grow in the vagina. Researchers are now studying the use of vaginal lactobacilli suppositories with oral metronidazole to treat and prevent BV.

In October 2003, another NIAID-funded project completed sequencing the genetic code of Trichomonas vaginalis. Researchers are beginning to understand its biology and to find new and innovative ways to prevent the disease. Trichomonas vaginalis is also of particular interest to biomedical researchers because of its role in HIV transmission, infant morbidity, and predisposition to cervical cancer. More information on this sequencing project can be found at http://www.tigr.org/tdb/e2k1/tvg.

MORE INFORMATION

National STD and AIDS Hotline
1-800-227-8922 or 1-800-342-2437 (24 hours a day, 7 days a week)

National Library of Medicine
MedlinePlus
8600 Rockville Pike
Bethesda, MD 20894
1-800-338-7657
http://medlineplus.gov

Centers for Disease Control and Prevention
1600 Clifton Road
Atlanta, GA 30333
1-888-232-3228
http://www.cdc.gov

NIAID is a component of the National Institutes of Health (NIH), which is an agency of the Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

Prepared by:
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892