What is prostatitis and how can it be avoided?

Infected prostate! An infection of the prostate, or an immune reaction to previous infection. Have protected sex, since stds are the most common causes in young males. Unprotected anal sex will invariably cause infection! oral sex can do so as well, albeit less likely.
Prostatitis. Prostatitis is most often caused by gram negative bacteria native to ones GI tract. Only occasionally is it thought to truly be a sexually transmitted disease. Because there is no way of identifying the organism as in other infections, antibiotics to cover the possibility of std are usually prescribed. Safe sex as always...