All answers refer to unlaundered pants worn by someone w/an STD. Crab, definitely. They can cling to the fabric and then attach to your pubic hair once you put the pants on. Other STD's I would say...
No. Chlamydia can damage the body, but the germ is gone after effective treatment is completed. Patients being treated should avoid oral, anal, and vaginal intercourse until 1-2 weeks have passed...