HIV & AIDS
HIV is a virus that invades the immune system and destroys it over time; reducing a person’s ability to fight off infections and cancer. People with HIV eventually develop AIDS, which is often fatal. You can get HIV from contact with infected blood or body fluids during vaginal or oral sex, and the risk is greatly increased if you have anal sex, multiple partners or shoot drugs. Infected pregnant girls can pass it on to their babies.

At first, you may just have short-lived, flu-like symptoms (tiredness, fever, aches). You may have no other symptoms for years. Even with no symptoms, you can still pass on the disease during sex. If you go on to get AIDS, you may get multiple infections that other people fight off easily. Most people with HIV can prolong their lives by carefully taking medicine every day for the rest of their life. These drugs are expensive, hard to take and have side effects.

Chlamydia
Chlamydia is the most common bacterial sexually transmitted disease. Most infected people—especially women—don’t have symptoms, so they can’t tell. Even without symptoms, infected people can pass chlamydia to every person they have sex with. When people with chlamydia do have symptoms, the symptoms may include pain when going to the bathroom or a “discharge" coming from the penis or vagina.

Chlamydia can be treated with antibiotics. But if you don’t know you’re infected, you won’t be looking for treatment. If you have had sex, see your doctor and get checked. Don’t put it off. If treatment is delayed, infected women can get a pelvic inflammatory disease (a serious complication of chlamydia). PID causes problems now (abdominal pain) and problems later (difficulty getting pregnant or infertility).

Genital Herpes
Genital herpes is a common infection caused by the herpes simplex virus, usually, HSV-2. Most people with genital herpes infection (HSV-2) don’t know they are infected. When symptoms are present, they often include blisters or sores in the genital area. Infected people can also have pain and burning when going to the bathroom. HSV-2 has a relative: HSV-1. Infection with HSV-1 causes cold sores and fever blisters, usually in and around the mouth. HSV-1 can also infect the genital area.

Antiviral medications help the symptoms, but can’t cure the disease. People who have one painful skin outbreak of genital herpes almost always have other outbreaks. If you have genital herpes—even if you don’t have blisters or sores—you can spread the infection during sex. And if you have genital herpes and have sex with a person who is infected with HIV, your chances for catching HIV increase.

HPV
Human papilloma virus (HPV)is a sexually transmitted viral infection that infects the skin and mucous membranes, including those in the genital area. HPV is transmitted two ways: by skin-to-skin contact and by contact with infected body fluids. It is most often spread by sex play or sexual intercourse (vaginal, anal or oral sex). HPV is the most common viral STD. Some people with HPV have warts on (or in) their genitals, but most people with HPV don’t know they are infected.

A Pap smear can detect HPV infection in women. Infection with certain strains of HPV causes cervical cancer in women. All sexually active women should have regular Pap smears so that cervical cancer and other problems caused by HPV can be recognized and treated. There is no cure for HPV. Because most people don’t know they have HPV, they don’t seek medical treatment. Warts caused by HPV can be treated, but treatment doesn’t guarantee the warts won’t return. Abnormal Pap smears and cervical cancer can be treated, but successful treatment depends on finding those problems early.

Gonorrhea
Gonorrhea is a bacterial infection that is primarily spread by sexual contact, including sexual intercourse, oral sex and anal sex. Most infected people—especially, infected women—don’t have symptoms, so they can’t tell. Even without symptoms, infected people can pass gonorrhea to every person they have sex with. When people with gonorrhea do have symptoms, they might experience pain when going to the bathroom or a discharge from the penis or vagina.

Gonorrhea can be treated with antibiotics. But if you don’t know you’re infected, you won’t be looking for treatment. If you have had sex, see your doctor and get checked. Don’t put it off. If treatment is delayed, infected women can get a pelvic inflammatory disease (a serious complication of gonorrhea). PID causes problems now (abdominal pain) and problems later (difficulty getting pregnant or infertility).

Syphilis
Syphilis is a highly contagious STD that’s caused by the bacterium Treponema pallidum. Syphilis is passed during oral, vaginal or anal sex through direct contact with highly infectious sores or patches that are usually on the genitals or mouth. Infected pregnant girls can also pass it on to their babies, causing major birth defects or miscarriages. 

You may get a painless ulcer (chancre) that goes away in a few weeks (primary syphilis). In people with untreated primary syphilis, the bacteria spreads through the blood stream, causing flu-like symptoms and a rash (secondary syphilis). If untreated, people with secondary syphilis may end up with tertiary syphilis, which can cause paralysis, blindness and conditions that can lead to the rupture of major blood vessels and death. Antibiotics can cure most syphilis infections and prevent further damage. However, they will not repair any damage already done.

Adapted from The Medical Institute, medinstitute.org.