What is an STD carrier?

A sexually transmitted disease (STD) carrier is a person infected with an STD (like HIV, herpes, crabs, syphilis, trichomoniasis, warts, chlamydia, and gonorrhea) who doesn't show outward (obvious) signs and/or symptoms of the infectious condition, thus potentially passing infection(s) unknowingly to one or more sexual partners (via unprotected sexual contact and/or sexual activities).