A sexually transmitted disease (STD) is an illness caused by an infectious pathogen that has a significant probability of transmission between humans by means of sexual contact, including vaginal intercourse, oral sex, and anal sex. Increasingly, the term sexually transmitted infection (STI) is used, as it has a broader range of meaning; a person may be infected, and may potentially infect others, without showing signs of disease. In addition, "disease" seems to have much more of a negative connotation than "infection." Some STIs can also be transmitted via the needles used in IV drug use, as well as through childbirth or breastfeeding. Sexually transmitted diseases have been well-known for hundreds of years.