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Sexually Transmitted Diseases

Gonorrhea, Chlamydia, Syphilis, Herpes, Human Papillomavirus

What are sexually transmitted diseases (STDs)?

Whenever humans come into close contact with one another, there is a chance that they will transmit communicable diseases to one another. Sexual intercourse, being the ultimate close contact, carries with it a high likelihood of passage of sexually transmitted diseases (STD) from person to person. No culture or society is safe from STDs. The Centers For Disease Control and Prevention (www.cdc. gov) estimates that about 12 million Americans acquire a STD each year, and the society spends billions of dollars a year to treat STDs.

A large number and variety of microbes are transmitted sexually. For some-like gonorrhea, chlamydia, syphilis, and HIV-sexual intercourse is the predominant mode of transfer of the disease, but for others sexual intercourse is only one of many routes of infection. This article concentrates on the diseases that are predominantly transmitted via sexual contact. It will not cover HIV and AIDS but will refer the reader to other articles exclusively devoted to this important disease.

Before discussing specific diseases, several general concepts regarding STDs need to be pointed out:

  • STDs "travel" together. Once one STD is detected in a patient, there is a much higher than average chance that others are also present. This is why doctors treat STDs with broad-spectrum or multiple antibiotics and run tests to make sure other infections are not present.
  • In a woman with an STD, pregnancy should also be ruled out because STDs occur commonly as a result of unprotected sex that also results in pregnancy.
  • The sexual partners of a person who has an STD must also be sought and treated because these partners almost always have the infection as well.
  • STD patients must be counseled regarding future prevention of STDs, especially HIV.


Gonorrhea is caused by a bacterium called Neisseria gonorrhoeae.

  • In men, depending on the mode of intercourse, this bacterium could infect the urethra, epididymis, and anus, and it may spread to blood and joints (arthritis) but only rarely. The most common symptoms are pain with urination and urethral discharge. In women gonorrhea could cause infection of the urethra, vagina, cervix, bladder, uterus, fallopian tubes, anus, and rarely of the blood and joints.
  • Many women have no or minimal symptoms, such as mild vaginal discharge. Left untreated, gonorrhea could cause infertility, pelvic inflammatory disease (infection of uterus and fallopian tubes), and even infections of the brain and heart.

A diagnosis is made by culture of the urethral-, vaginal-, or cervical secretions- or urine, which is an attempt to grow the bacteria in a culture medium for identification. Gonorrhea is treated with penicillin, doxycycline, ceftriaxone, ciprofloxacin or azithromycin.


Chlamydia is caused by a small bacteria-like organism called Chlamydiae trachomatis.

  • In men it causes infection of the urethra, epididymis, groin lymph nodes, anus, and rarely joints. It is also a cause of genital sores (ulcers). The most common symptoms are pain with urination and urethral discharge.
  • In women it infects the vagina, urethra, cervix, bladder, uterus, fallopian tubes, groin lymph nodes, anus, and rarely the joints. Left untreated, chlamydia could cause infertility and pelvic inflammatory disease (infection of uterus and fallopian tubes).

Diagnosis is by culture of the vaginal-, cervical- or urinary secretions. Treatment is with doxycycline, azithromycin or erythromycin.


Syphilis is caused by a bacterium called Treponema pallidum.

  • It first presents as a painless genital ulcer. If ignored and left untreated, the ulcer (also called chancre or primary syphilis) goes away, but later, in approximately one to two months, emerges again as a red rash, fever, head and body aches, and enlarged lymph nodes.
  • This stage, called secondary syphilis, lasts for up to one year. Some people remain in this stage forever and have mild or no more symptoms. However, one-third to one-half of the patients proceed to tertiary syphilis, which starts about ten years after the initial infection.
  • Tertiary syphilis is the result of tissue destruction and could affect any part of the body, including the skin, nose, tongue, brain, or internal organs. The most serious area of involvement is the cardiovascular system, where the Aorta (the main artery supplying the body) gets infected and weakens. The weakened area dilates and becomes an aneurysm. This could lead to undue stress on the heart valves and heart failure.

Primary syphilis is diagnosed by direct observation of the bacteria obtained from the genital sores under the microscope. Secondary and tertiary syphilis are diagnosed by blood tests, in which human antibodies to the bacteria are detected. These antibodies are present because the body makes them to fight the infection. The drug of choice for treatment of syphilis is penicillin, but doxycycline and tetracycline are also effective.


Herpes is caused by two Herpes viruses: Herpes Simplex type I and II (HSV I & II). The genital herpes is most commonly caused by HSV II. It can cause infection of the urethra, vagina, vulva, and anus. The lesions are similar to acne but are itchy, painful and tend to recur every few weeks to months. The outbreaks become less frequent and less severe with time. The sores are highly contagious. Diagnosis is through the culture of the sores or direct observation of the infected cells under the microscope. As of yet, there is no cure for HSV, but several antiviral medicines that reduce the severity of the infections are available.

Acyclovir online

Famvir (Famciclovir), Valtrex (Valacyclovir)

Human Papillomavirus

This viral infection of the vagina, vulva, cervix, and penis is caused by a number of different viruses, all belonging to the Human Papilloma group (HPV). These viruses cause genital warts and, more importantly, could cause cancer of the cervix, vagina, vulva, and penis. The main reason for the routine Pap smears in women is to detect HPV infection and treat the diseased area before it becomes cancerous. Scrapings of the affected areas of the skin, cervix, or vagina provide the diagnostic material. Treatment is surgical removal of the area.

Other STDs

Besides gonorrhea, several other organisms could cause infection of the urethra, and they are collectively called non-gonococcal urethritis (NGU). The main cause of NGU is chlamydia, as described above. Other common and important organisms causing NGU include Ureaplasma urealyticum, Trichomonas vaginalis, and Herpes Simplex virus. Ureaplasma is treated with doxycycline and Trichomonas with metronidazole (Flagyl).

Besides syphilis and herpes, causes of genital ulcers include infections by other bacteria called Haemophilis ducreyi, Chlamydiae tricomatis, and Calymotobacterium granulomatis.

Pubic lice or "Crabs" is caused by an insect called Pthirus pubis that is also sexually transmitted. Scabies is caused by a mite (Sacroptes scabiei). Both these insects are diagnosed by visual inspection, and both organisms are killed by insecticide lotions containing malathion or carbaryl (such as Lindane).

Although not the primary route of infection, Hepatitis B and C viruses can also be transmitted sexually. These viruses enter the blood stream and eventually cause infection of the liver. They could cause a spectrum of damages, from minimal problems to death.

Last updated 6 April 2018