Cause: A tiny animal (protozoan) called Trichomonas vaginalis(`trich' for short).

Incubation Period: four to 28 days.

Transmission: By and insertive vaginal intercourse. It is much more common in women, and doesn't grow well in the penis, mouth, or anus. It is easily passed from vagina to vagina by secondary contact. Often, when a person has trich, they also have gonorrhea, but this isn't always the case. If you do have trich, it's good to get tested for other diseases.

Trich can also be latent. This means it will live in the vagina without causing any problems. That is, until something happens that makes it cause infection. For example, taking certain antibiotics can make trich 'come to life'! It's also been reported that trich has infected people who have gone into dirty stagnant pools or ponds.

What to Look For: This disease usually affects women, but men can be carriers who don't show any symptoms. When men do have symptoms, there will be a discharge from the urethra. In women, there is a smelly, frothy discharge from the vagina, itching, burning, and redness. There might not be symptoms, or if there are, then they'll be pretty light.

Treatment: Oral medications are used and usually work well. This disease is curable.

Complications: In really bad cases, the thighs may become raw and infected. It gets worse during pregnancy and when a woman gets her period. There is a link between trich and cervical cancer.

Contact your health provider as soon as you think you may have gotten an STD; the sooner you are treated, the better your chances of recovery, and it is less likely you will get complications. Also, have your partners checked out, and stop having sex until you get better. Otherwise, you and your partners could keep passing the disease back and forth to each other.

Having a trich infection makes it easier for secondary or opportunistic infections to happen. This is especially true for HIV, which can easily get into your body if your urethra is irritated. Also, if you have HIV and trich, then you are more likely to transmit HIV to another person.