Answer: The sexually transmitted infection that usually fails to reveal obvious symptoms in women is <u>syphilis</u>.
Explanation: Syphilis is a sexually-transmitted infection, that is to say that it is a contagious disease spread by sexual activity or close contact with an infected person. The bacteria <em>Treponema pallidum </em>is the one that causes syphilis. Moreover,<u> a woman that has syphilis may not feel nor see any symptoms, which means that, in some cases, syphilis' symptoms may not even be noticed. </u>
