Because Trichomonas vaginitis is a STD that can be transmitted during sexual activity, you can help to prevent infection by:
Not having sex
Having sex with only one uninfected partner
Consistently using male latex condoms during sexual intercourse, with or without a spermicide
To help prevent vaginitis, you can:
Keep the area around your genitals clean and dry.
Avoid irritating soaps and bath additives, vaginal sprays and douches.
Change tampons and sanitary napkins frequently.
Wear loose cotton underwear that doesn't trap moisture. Avoid nylon underwear.
After swimming, change quickly into your dry clothing instead of sitting in your wet bathing suit for long periods.