Transcript
Classification
STD may refer only to infections that are causing diseases, or it may be used more loosely as a synonym for STI. Most of the time, people do not know that they are infected with an STI until they are tested or start showing symptoms of disease. Moreover, the term sexually transmissible disease is sometimes used since it is less restrictive in consideration of other factors or means of transmission. For instance, meningitis is transmissible by means of sexual contact but is not labeled as an STI because sexual contact is not the primary vector for the pathogens that cause meningitis. This discrepancy is addressed by the probability of infection by means other than sexual contact. In general, an STI is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact (more sophisticated means—blood transfusion, sharing of hypodermic needles—are not taken into account). Thus, one may presume that, if a person is infected with an STI, e.g., chlamydia, gonorrhea, genital herpes, it was transmitted to him/her by means of sexual contact. The diseases on this list are most commonly transmitted solely by sexual activity. Many infectious diseases, including the common cold, influenza, pneumonia, and most others that are transmitted personto-person can also be transmitted during sexual contact, if one person is infected, due to the close contact involved. However, even though these diseases may be transmitted during sex, they are not considered STIs.
Cause
Danish poster raising awareness about safer sex
Sexually transmitted diseases (STDs) are diseases that are mainly passed from one person to another during sexual contact. The term sexually transmitted infection (STI) is increasingly being used instead of STD, because some sexually transmitted infections, such as chlamydia, do not cause any pain or unpleasant symptoms such as blisters. Many people may never know that they have been infected unless they are tested in a clinic.
However, having no symptoms does not mean that someone does not have an infection that needs treating or an infection that can lead to a disease or medical condition. The common way to prevent the transmission of STIs or STDs is to avoid unprotected sexual contact, whether it is vaginal, anal or oral. However, some STIs or STDs such as herpes can still be passed even if a condom or dental dam is used. It is important to educate yourself about how STIs or STDs are transmitted and how to safeguard your sexual health, including identifying symptoms and seeking medical help early. Under STD/STI topics, you will find links to pages that contain more information about common STDs/STIs, including: how to prevent transmission, information about treatment and STD symptoms and pictures, where applicable.