Some of these microbes are known to be sexually transmitted.Many STIs are (more easily) transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and (less often—depending on type of infection) the mouth, throat, respiratory tract and eyes.
Some treatment facilities utilize in-home test kits and have the person return the test for follow-up.
The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer with an infected partner.
Not all sexual activities involve contact: cybersex, phonesex or masturbation from a distance are methods of avoiding contact. Although a condom is effective in limiting exposure, some disease transmission may occur even with a condom.
Therefore, the old condom must be properly disposed of.
A new condom is used for each act of intercourse, as multiple usage increases the chance of breakage, defeating the effectiveness as a barrier.
In the case of HIV, sexual transmission routes almost always involve the penis, as HIV cannot spread through unbroken skin; therefore, properly shielding the penis with a properly worn condom from the vagina or anus effectively stops HIV transmission.