I have had it before. My doctor said it was sexually transmitted but I have heard different. I found this:

Trichomoniasis is caused by the single-celled protozoan parasite, Trichomonas vaginalis. The vagina is the most common site of infection in women, and the urethra (urine canal) is the most common site of infection in men.
The parasite is sexually transmitted through penis-to-vagina intercourse or vulva-to-vulva (the genital area outside the vagina) contact with an infected partner. Women can acquire the disease from infected men or women, but men usually contract it only from infected women.

The surest way to avoid transmission of sexually transmitted diseases 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.

Latex male condoms, when used consistently and correctly, can reduce the risk of transmission of trichomoniasis.

Any genital symptom such as discharge or burning during urination or an unusual sore or rash should be a signal to stop having sex and to consult a health care provider immediately. A person diagnosed with trichomoniasis (or any other STD) should receive treatment and should notify all recent sex partners so that they can see a health care provider and be treated. This reduces the risk that the sex partners will develop complications from trichomoniasis and reduces the risk that the person with trichomoniasis will become re-infected. Sex should be stopped until the person with trichomoniasis and all of his or her recent partners complete treatment for trichomoniasis and have no symptoms.

Men can carry STD's and not experience any symptoms for a long time. A year seems like a stretch, though. I'd have a chat with the bf.

I am trying to figure out if they can tell when your body came into contact with the virus. I really need to know, that I could warn a possible victim. Is it possible that a man can carry it in his blood, after having been treated? Does is come from them being unclean, or do they have to sleep with someone with the virus to carry the virus?

Honestly the most common way to get it is through sex but you can get it from the toilet seat and maybe even from a movie theatre if there was a girl wearing a skirt sitting there before you. I mean, it's even founf in women who are NOT sexually active so I don't know why they call it an STD. I'm clean and i've gotten it before. If you are tresated it does not carry in the blood and it is not very easy for a male to pick up an infection like that.

Thanks that helps a little bit. I am trying to figure out if it came from my boyfriend. He was diagnosied but was treated just in case. I just wanna know where it came from. Is there any way that they can tell that?

No they can't tell how you got it.

Trichamonas is a sexually transmitted disease, period! Genereally spread from an infected male or female to a female. But can be spread either way. You can not get it from toilet seats, towels, etc. Trichamonas do not live outside of the body for but maybe 30 to 60 minutes. Men may possibly have the parasite and not know it and it is more prevelant in uncircumcised men, but it is sexually transmitted. If you have been faithful it may be time to talk to your boyfriend.

Can it be transmitted by a male touching another female that has the std and take it back to his partner by hand within those 30 to 60 minutes?