Chlamydia

So ladies I have a couple (3) questions.

> Lets say there are 2 virgins and they have unprotected sex alot could they start their own type of sexual transmitted disease?

>So lets just say someone had chlamydia before, took the pill, got treated, tested again and it came back negative. Is it possible that the person could still pass it on to someone else they have unprotected sex with?

>Last question, if someone who had chlamydia before and got treated for it get it again if they have sex with a virgin? Or possibly give it to them?