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11.4. Main sexually transmitted diseases and prevention

The sexually transmitted diseases (STDs) are diseases that are transmitted having sex with other people infected by various bacteriaviruses, fungi and arthropods that can develop or live in body fluids. Although they usually affect the genital organs, many of them also affect other organs.

Although most STDs have a treatment that can be cured, it is necessary to take the necessary measures to avoid contagion.

The main sexually transmitted diseases

Sexually transmitted diseases are very common and the number of people affected is increasing due to various causes:

  • Existence of greater freedom in sexual relations.
  • Do not use condoms in sexual intercourse (promiscuity in itself does not have to promote contagion, since you can have only one partner and if you do not use a condom it can transmit an STD).
  • Loss of fear of death from AIDS. Before, contracting HIV was synonymous with death, but with advances in antiretroviral drugs, the expectation and quality of life of patients has greatly increased, thus reducing precautions.
  • The abuse of antibiotics has generated resistant microorganisms.

The main sexually transmitted diseases are:


It is caused by the bacterium Neisseria gonorrhoeae, so this bacterium can be fought with antibiotics.

It is transmitted through sexual intercourse. It is not contagious by using public services, sharing towels, etc.

Symptoms appear three days to three weeks after sexual intercourse, and in men are itching when urinating and the production of a purulent discharge from the penis. In women, increased vaginal discharge and abdominal pain due to inflammation in the uterus, which can lead to sterility.

News: The rise of gonorrhea in Spain.

Disinformation (ok diario): Gonorrhea caused by the cells of a virus ... (Taken from Dr. Bioblogo)


It is caused by the bacterium Treponema pallidum, so it can be treated with antibiotics If left untreated, it can be very serious, even fatal.

It is transmitted through sexual intercourse, but it can also pass from the mother to the fetus.

Symptoms appear one to twelve weeks after contact. Reddish ulcers first appear on the sexual organs, anus, or mouth. When the disease progresses, they appear in other parts of the body and lumps in the neck, armpits, groin, etc. After three years the heart, spinal cord and brain are affected, producing dementia.

Curiosity: Al Capone


It is caused by the bacterium Chlamydia trachomatis, so it can be cured with antibiotics. It is transmitted by contact with the mucous membranes of the vagina, mouth, eyes, urethra or rectum. Also a pregnant woman can infect her child during childbirth.

The most characteristic symptoms in men is the urgent need to urinate, burning when urinating, inflammation of the testicles, and in women, thick and yellowish vaginal secretions, burning when urinating, discharge from the urethra, pain during sexual intercourse, etc. It can cause sterility in both sexes. In children it can cause pneumonia, eye infections, and blindness.

Genital herpes

Caused by the Herpes simplex virus or HSV. It causes painful blisters and sores on the genitals, as well as painful urination and lumps in the groin.

It is transmitted by vaginal, anal, and oral sexual contact, and sometimes through skin wounds. People who do not have sores can transmit the virus.

The virus remains in the body forever, and outbreaks often repeat themselves, especially in the first year. There is no cure, but antivirals and other medications can provide relief.

Hepatitis B

It is caused by the hepatitis B virus (HBV) that infects the liver and carries a high risk of death from cirrhosis and liver cancer. There is a vaccine to prevent this disease.

The virus is transmitted through sexual intercourse, breast milk, and through contact with blood or other bodily fluids, such as sharing contaminated hypodermic syringes or razor blades or getting a tattoo with contaminated instruments.

Symptoms appear one month after infection. For example, extreme fatigue, headache, yellowing of the skin and eyes (jaundice), dark urine, nausea and vomiting, abdominal pain, and general malaise.

AIDS (Acquired Immune Deficiency Syndrome)

The human immunodeficiency syndrome (AIDS) is caused human immunodeficiency virus (HIV). It causes the destruction of T lymphocytes, which are responsible for the immune response, so that the affected person is left without defenses, with a weak immune system, unprotected against any possible infection.

The person can be a carrier of the virus even if they do not manifest the disease, and yet they can transmit it. Is transmitted by semen, the vaginal secretion and blood also transmitted from pregnant mother to the fetus.

It cannot be cured, although currently antiretrovirals have made it possible to treat the disease much better.

% de personas infectadas por VIH en el mundo

By User:PDH (Based on UN data from [1] 2011.) [Public domain], via Wikimedia Commons

Human papilloma

The human papilloma virus is an infectious disease caused by the virus of human papillomavirus (HPV), being the ETS more common. There is a vaccine to prevent it.

Although it is transmitted mainly through sexual contact, it is by skin-to-skin contact, there is no need for fluid exchange like AIDS.

An infected person may not have any symptoms and years may go by without them showing up. Its main symptom is the appearance of warts on the genitals of men and women, as well as irritations at the entrance to the vagina with a burning sensation during sexual intercourse.

The human papillomavirus can cause cervical cancer.

Activity: Sexually transmitted diseases.

Activity: Questions about STDs.

Presentation: Sexually Transmitted Diseases (contains images not suitable for all people).

Answer in your notebook

11.14.- What does it depend on whether a person has a higher risk of contracting AIDS?

Answer in your notebook

11.15.- What contraceptive method, in addition to avoiding unwanted pregnancies, prevents the spread of STDs?


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