Sexually transmitted diseases are infective diseases that are transmitted through sexual contact, which means that semen, blood, saliva and other body fluids that are coming from people with STD are highly contagious. Although many people think that this is not so serious, CDC estimates that nearly 20 million new sexually transmitted infections occur every year in the United States accounting for almost $16 billion in health care costs annually with 25% of these occurring in someone between the ages 16 and 19. More than 2 million cases of the three nationally reported STDs – chlamydia, gonorrhea, and syphilis – were reported in the United States in 2016, the highest number ever. 
The most common sexually transmitted diseases
The most common sexually transmitted disease is definitely a Chlamydia infection.
Chlamydia infection is caused by the bacteria called Chlamydia trachomatis. The most common symptoms are an abnormal genital discharge and burning while urinating. Unfortunately, Chlamydia doesn't usually cause any symptoms, so you may not realize that you have it.
Symptoms in women include
- Abnormal vaginal discharge, which may have a strong smell
- A burning sensation when urinating
- Pain during intercourse
- If the infection spreads, you might get lower abdominal pain, pain during sex, nausea, or fever.
Symptoms in men include
- Discharge from your penis
- A burning sensation when urinating
- Burning or itching around the opening of your penis
- Pain and swelling in one or both testicles (although this is less common)
If not treated on time, it can lead to much more severe health problems such as lower abdominal pain, lower back pain, nausea, fever, bleeding and pain during the intercourse, and finally infertility. In women, an untreated infection can spread to the uterus and fallopian tubes, causing pelvic inflammatory disease, which can cause permanent damage to your reproductive system, leading to long-term pelvic pain, infertility, and ectopic pregnancy.
Chlamydia infections can be treated with antibiotic therapy, either with a one-time dose of the antibiotics or a 7-day course. If Chlamydia infection caused any damage to your reproductive system, this could not be reversed. Your partner should be treated too, and you two should not have sex until the infection has cleared up. 
Acquired Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome (AIDS) is probably the most serious and life threatening sexually transmitted disease today in all parts of the world. It is caused by the human immunodeficiency virus (HIV) and it is considered a sexually transmitted disease because the virus can be found in almost all body fluids, including sperm, vaginal discharge, saliva and others. This is a very serious and incurable disease. It doesn’t kill you itself, instead, it makes you more prone to all other kinds of infections by reducing your immunity to the minimum.
Target cells for the human immunodeficiency virus are T- helper lymphocytes, which are the base of the cellular body defense.
Not HIV nor AIDS can be cured, but are manageable with a combination of antiretroviral (ART) drugs: TDF (tenofovir) either 3TC (lamivudine) or FTC (emtricitabine) and EFV (efavirenz).
These are also one of the most common sexually transmitted diseases, and they are caused by a Human Papillomavirus. The most common symptom is a skin formation called condyloma. These condylomas appear on genitals and can spread to the surrounding skin. They are highly contagious and can progress into several other symptoms such as headaches, muscle aches, pain when urinating, itching, burning, or swollen glands in the genital area. In most cases, it requires no therapy what so ever because the skin lesions disappear them selves in two to four weeks.
There is no cure for HPV, but genital warts can be removed. There are special, prescription-only treatments for genital warts, do not use medication used for non-genital types of warts. Surgery is also an option. Treatment can only remove the genital wart. Treatment does not cure HPV, the virus that causes genital warts. However, if you have problems with warts, your doctor may :
- Use an electric current to burn off the warts
- Use a light/laser to destroy warts
- Freeze off the warts
- Cut out the warts
Hepatitis B is also considered a sexually transmitted disease. Although in most cases it is caused by infected needles, sexual intercourse is also one of the most common ways to get infected. It is caused by Hepatitis B virus and one of the diagnostic problems is the fact that it doesn’t cause any changes to the genitals. It primarily hits the liver causing inflammation, cirrhosis and even cancer in late stages of the disease. More than 250 million people are living with hepatitis B virus infection, and in 2015, almost one million people worldwide died due to hepatitis B complications, which includes cirrhosis and hepatocellular carcinoma. Hepatitis B can be prevented by currently a vaccine.
Herpes is the same virus (herpes simplex 1) that is causing the small blister-like lesions on facial region and lips and is also responsible for a serious sexually transmitted disease called Genital herpes (herpes simplex 2). The symptoms are almost the same as they are on human face - painful blisters or open sores but this time in the genital area, buttocks or anywhere else on the skin.
Like with all viral infections, there is no cure for it but the good thing is that these lesions disappear by themselves in a couple of days. The fact is also that the patient will carry the virus in his body for the rest of his life. According to some studies, more than 45 million Americans are infected with HSV at this moment. The virus can spread even when sores are not present.
Pregnant women with active sores during delivery should give birth by a C-section to avoid transmission to a newborn for whom the infection could be deadly.
Gonorrhea is a serious sexually transmitted disease caused by a bacterium called Neisseria Gonorrheae. Nowadays more than 700,000 persons in the U.S. get gonorrheal infections each year. In most cases, females don’t have any symptoms, which can be very dangerous from the epidemiological point of view. Males can have problems with burning sensation when urinating, or a white, yellow, or green discharge from the penis.
Untreated gonorrhea can cause serious health problems such as pelvic inflammatory disease, epididymitis and many others. It can be cured with several antibiotics but every year there is more and more drug-resistant strains of gonorrhea, which makes the successful treatment much more difficult.
Syphilis is a very serious sexually transmitted disease, which, if left untreated, can even become deadly. A spiral-shaped bacterium called Treponema pallidum causes it. The incidence of the syphilis has increased dramatically in recent years. Many experts believe that it is because the first symptoms of this terrible disease may go undetected. The first symptoms are very mild and disappear spontaneously in a few days. However, later, the bacterium attacks brain, heart and almost all the internal organs.
The most common symptom is a single, painless sore on the penis or on the vagina called ulcus durum, which is the sign of the first stadium of the disease. Later, as the disease progresses, people get skin rash on the hands and feet that usually does not itch and clears on its own, fever, swollen lymph glands, sore throat, headaches and weight loss.
Penicillin is still the first choice of weapon against this terrible disease, but it works only if the syphilis is discovered early.
You should get tested for syphilis if you are sexually active and you are
- are a man who has sex with men;
- are living with HIV; or
- have partner(s) who have tested positive for syphilis.
Prevention of the sexually transmitted diseases
There are also several things a person can do to reduce the possibility of infection. If two people decide to stay in a monogamous relationship, there is a much smaller risk that one of them will be infected with an STD.
A condom should be used during every sexual intercourse, including vaginal, anal, or oral sex, although they don’t offer a 100% protection.
There is one important thing that every sexually active person should know: everyone should have regular gynecological or dermatological checkups for STDs, especially when starting a relationship with a new sexual partner.
During the intravenous application of some medication or insulin, only clean needles should be used. When a person finds out that he is infected with some sexually transmitted disease, he should avoid all sexual activity while being treated.
Incidence of STDs
The fact is that the incidence of STDs has been rising in the past couple of years and most experts believe that the real cause of this is the fact that the young people are becoming sexually active much earlier than they were for example 30 years ago.
Another group of experts believes that the problem isn’t the timing but in the today’s trend to have multiple sexual partners during a lifetime, which potentially puts people at very high risk of developing contracting STDs.
Experts believe that females are, from the epidemiologic point of view, much more endangered than the males. In most of that sexually transmitted diseases, symptoms in women are rather mild and really can go undetected. Women don’t know that they are infected, and that is more than enough for a real epidemic.
Vertical transmission of several sexually transmitted diseases is possible. Some STDs can be passed from a pregnant woman to the baby while the woman is pregnant and during the childbirth.
For example, syphilis can cross through the placenta and that’s why the baby may be born infected.
Some other sexually transmitted disease such as Gonorrhea, Chlamydia, hepatitis B, and genital herpes can't pass through the placenta, but they can be given on a baby during the act of delivery, while baby passes through the birth canal.
Some of these diseases passed on the baby can be treated soon after, but some can lead to severe body defects and even death.
The prognosis varies among the different diseases.
However, there is one rule that works with all of them - the sooner the disease is detected, the higher are the chances for a (complete) recovery.
The prognosis for the recovery from those sexually transmitted diseases caused by bacteria is better because there are some powerful antibiotics which are very effective.
The problem comes with the treatment of the STDs that are caused by a virus. There are no medications that can kill a virus. This is because it incorporates in our cells. Anyway, there are several medications made to prevent the virus from multiplying. For this reason, patients can be treated on a long-term basis to relieve symptoms and prevent life-threatening complications, which improves the quality of their lives.
There are also some other diseases which are considered to be a STDs such as Trichomoniasis, Bacterial vaginosis, Cytomegalovirus infections, Scabies and Pubic lice and usually not life-threatening.
Read More: STDs are Still a Huge Problem in U.S.
Every change in your genitals should be reported to a physician. By “every change,” in most cases, we refer to:
1. abnormal vaginal discharge,
2. vaginal burning and itching,
3. unusual pain in a pelvic area while having sex,
4. strange blister-like formations on genitals,
5. discharge from the tip of the penis,
6. swelling of the lymph nodes,
7. skin rashes over large parts of the body and many others
Doctors will test you for a sexually transmitted disease and, in most cases, it will be performed by a gynecologist, a specialist in disorders of the urinary tract and the male sexual organs called urologist, a family physician, a dermatologist or even a nurse. The tests are strictly confidential, and no name of the patient will be revealed!