Sexually Transmitted Diseases - Types, Prevention and Treatment

Sexually transmitted diseases (STD), also called venereal diseases, are a major public health problem in all countries. There are several different types of STD, some more serious, some milder.

Some sexually transmitted diseases can lead to death, whether due to compromised immune systems, as in the case of HIV, or by increasing the risk of malignant tumors, such as cases of hepatitis B and HPV. Other common complications of sexually transmitted diseases are infertility, urethral injury, and pelvic inflammatory disease.

In this article we will do a quick review on the most common types of sexually transmitted diseases. Let's address your forms of transmission and the most common symptoms. If you want more information about specific diseases, use the links that will be provided throughout this article.

Sexually transmitted diseases
Sexually transmitted diseases

What are the most common STD?

There are several sexually transmitted diseases, caused by different types of germs, including bacteria, viruses, parasites and protozoa. Among the most common STDs, we can mention:

Of the STDs cited above, those with the highest incidence, in descending order, are HPV, chlamydia, trichomoniasis and gonorrhea.

Candidiasis, hepatitis A and bacterial vaginosis (infection by Gardnerella bacteria) are not considered sexually transmitted diseases, although they may eventually be transmitted by this route. Similarly, some intestinal infections, such as amebiasis, giardiasis, shigellosis and others, can be transmitted through the sexual pathway if contaminated feces are contacted, such as anal penetration or anilingus (oral sex in the anus).

To be considered an STD the disease must have the sexual route as the main mode of transmission.

How do you get an STD?

It seems a bit obvious to ask how to get a sexually transmitted disease, however, most STDs can be transmitted through other than sexual pathways.

For example, HIV and Hepatitis B and C can be transmitted through contaminated needles, blood transfusion or mother to child during pregnancy. Syphilis can be transmitted through the kiss if there are lesions in the mouth. Pubic pediculosis (boring) can be transmitted through towels or underwear.

Therefore, STD is a disease that is preferentially, but not necessarily, transmitted through the sexual pathway.

Of the three sexual pathways (anal, vaginal and oral), the anal route is the one with the highest risk of transmission and contamination. Just to get an idea, a man who is passive in an anal intercourse with a contaminated partner is 30 times more likely to become infected with HIV than a man who is active in a vaginal relationship with a contaminated partner.

Some STDs are more contagious than others. The risk of contamination with a single vaginal intercourse is much greater for diseases such as hepatitis B, gonorrhea and chlamydia than for HIV, syphilis and HPV, for example.

Oral sex is the form with the lowest rate of transmission, but it is not without risks. The person who receives the oral sex usually has less risk, because his genital organ only has contact with the saliva. The partner who provides oral sex is at greater risk because it has contact with contaminated vaginal or penile secretions.

In general, homosexual women or men are at greater risk of contamination than heterosexual men. The lowest risk occurs in homosexual women, as long as no dildos or any other object is shared for penetration.

Having an STD increases your risk of having others. Individuals with genital herpes or gonorrhea, for example, if they have sex with people with HIV greatly increase their risk of contamination. The inflammation and the genital lesions caused by an STD favor the contagion by other STDs.

Risk factors

The main risk factor for contracting a sexually transmitted disease is to have an active sex life. The best way to prevent STDs is not to have sex. However, this is a viable option for only a minority of people. In those who do not intend to practice celibacy, using condoms and not having a promiscuous life is the best course.

When the population that has or has had some venereal disease is studied, some data are frequently found and can be characterized as risk factors for contamination. Through these studies it is possible to state that sexually transmitted diseases are more common in people who have the following characteristics:
  • Age between 15 and 24 years
  • Not married
  • Multiple sexual partners
  • Early initiation of sexual life
  • Practice sex without condoms
  • Frequent consumption of alcohol
  • Drug users
  • Sex with prostitutes

In addition to the above factors, individuals who have had an STD are at greater risk of having other STDs.


The group of sexually transmitted diseases is quite heterogeneous, so the symptoms are very varied. In a didactic way, we can divide the STD clinical picture into 3 large groups.

1. Urethral discharge (urethritis)

Inflammation of the urethra, a channel that drains urine, is the main feature of several STDs. The most common symptoms of urethritis are burning to urinate, called dysuria and penile or vaginal discharge. In women, in addition to discharge there is pain and vaginal bleeding.

Gonorrhea, chlamydia, trichomoniasis, and other less common causes such as Mycoplasma genitalium and Ureaplasma urealyticum infections are the main STDs that have urethritis as the main characteristic.

2. Genital ulcers

Another common manifestation of sexually transmitted diseases is the appearance of ulcers in the genitals. STDs with this characteristic are syphilis, donovanose (inguinal granuloma), lymphogranuloma venereum, genital herpes, and soft cancer.

Each STI usually forms ulcers with its own characteristics. For example: syphilis courses with a painless and clean ulcer; soft cancer with painful and purulent ulcer; herpes usually have multiple small, very painful ulcers, etc.

In women, ulcers may appear inside the vagina and are not easily visible. In syphilis, which occurs with painless ulcer, the lesion may even go unnoticed.

3. General symptoms

Sexually transmitted diseases may also present with systemic symptoms due to involvement of internal organs.

PID (pelvic inflammatory disease) is a serious infection of the female reproductive organs such as uterus, fallopian tubes and ovaries. It may be a complication of gonorrhea or chlamydia.

Inflammation of the liver is typical of hepatitis B and C, but may also occur in disseminated gonorrhea and secondary syphilis.

HIV can cause fever, pharyngitis and the appearance of lymph glands throughout the body.

In general, each STD has its specific symptoms. It is necessary to read individually about each disease to know its symptoms.


As has been said, the best way to prevent STDs is not to have sex. However, this orientation is impracticable for the vast majority of the population. Therefore, we need to think about other ways of preventing venereal diseases.

Vaccines are highly efficient methods for disease prevention. The problem is that currently there are only vaccines for two STDs: HPV and hepatitis B.

Therefore, the most effective preventive method against sexually transmitted diseases is still the condom. Condoms are not a 100% effective method but have a fairly high success rate.

Studies show that condoms made from latex and polyurethane are impenetrable to HIV viral particles. The material is highly secure. Failures usually arise from misuse of the condom, allowing it to leave the penis or break during intercourse. In general, condom use reduces the risk of HIV transmission by up to 90%.

The condom is also very effective in preventing other STDs, especially gonorrhea in men. For reasons not yet well understood, the STD that presents the lowest rate of prevention with the condom is trichomoniasis. Even so, regular condom use reduces the chance of contamination by more than 30%. Condom may not be a perfect method, but it is still much better than having unprotected sex.

The condom is ineffective against pubic pediculosis, popularly known as boring. This disease is caused by a type of lice that lodges in the pubic hair, an area not covered by the condom. Therefore, during sexual intercourse, the intimate contact between the pubic hair areas is not avoided by the use of the condom, making this method ineffective against the transmission of Phthirus pubis , the causative agent of pubic pediculosis.

In men, circumcision is an effective way to reduce the risk of STD contamination. Studies have shown that circumcised men are up to 50% less likely to become HIV-infected through intercourse with women than men who did not undergo circumcision. This benefit is only proven in heterosexual relationships.

Circumcision protects only man. The rate of transmission of HIV to women is the same regardless of whether or not the man is circumcised.

Circumcision also appears to decrease the rate of man's infection against syphilis, herpes, and HPV, but not against gonorrhea, trichomoniasis, and chlamydia.


The treatment of STDs obviously depends on their cause. Some STDs have a cure, some do not.

Infections such as syphilis, gonorrhea, chlamydia, lymphogranuloma, and trichomonas can be cured with appropriate antibiotics.

Hepatitis B and C infections have treatment, but the cure rate is not high. Many patients live chronically with these infections.

HIV has treatment, but it still has no cure. The same goes for genital herpes.

HPV has no treatment, but in many cases the body can spontaneously get rid of the virus. The problem is the increased risk of cervical cancer that women have.

To learn more about sexually transmitted diseases, access the links provided in this text to read about each of the STDs described here.

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