While AIDS (SIDA in Spanish) is the most lethal of sexually transmitted diseases (STDs) and gets the most press, other STDs are far more prevalent and also serious if left untreated. All are spread by unprotected sexual conduct; use of latex condoms reduces the possibility of contracting sexually transmitted diseases, but does not eliminate it.

Most STDs, including gonorrhea, chlamydia, and syphilis, are treatable with antibiotics, but some strains have developed immunity to penicillin and alternative treatments. If taking antibiotics, complete the prescribed course, since an interrupted treatment may not kill the infection and could even help it develop immunity.

The most common STD is gonorrhea, characterized by a burning sensation during urination, and penile or vaginal discharge; it may cause infertility. Chlamydia has milder symptoms but similar complications. Syphilis, the only major New World disease to spread to Europe after the Spanish invasion, begins with ulcer and rash symptoms that soon disappear; long-term complications, however, can include cardiovascular problems and even mental derangement.

Herpes, a virus causing small but irritating genital ulcers, has no effective treatment. It is likely to recur, spreads easily when active, and can contribute to cervical cancer. Hepatitis B, though not exclusively an STD, can spread through the mixing of bodily fluids such as saliva, semen, and menstrual and vaginal secretions. It can also spread through unsanitary medical procedures, inadequately sterilized or shared syringes, during body piercing, and under similar circumstances. Like hepatitis A it can lead to liver damage but is more serious; vaccination is advisable for high-risk individuals, but it’s expensive.