Sexually Transmitted Diseases: Definition, Classification, & Causes

The term disease refers to any deviation from health. It is a destructive process in an organ or organism with a specific cause and symptoms. A number of disease-causing microbes can be introduced to the body during sexual activity and negatively affects the genital and other body organs and organ systems. However, the earlier symptoms of Sexually Transmitted Diseases are mild and not noticeable.

It is important to note that one should not avoid or escape from the severity of sexually transmitted diseases that leads to major and permanent damage to our body organs. In this article, we will study about Sexually Transmitted Diseases in detail. Scroll down to find more about STDs!

What are Sexually Transmitted Diseases?

Diseases that are most frequently transmitted through sexual intercourse and sexual activity are called sexually transmitted diseases. The contact is usually oral, vaginal, or anal sex; however, they can also spread by hypodermic needles and by blood transfusion. These are also called venereal diseases.

It is important to note that not all STDs are transmitted by sexual activities. Some of the STDs are transmitted due to non-sexual activities also. Some of the examples of non-sexual activities involve the exchange of syringes, breastfeeding, blood transfusion, etc.

Classification of Sexually Transmitted Diseases (STDs)

Following are the basis of classification of sexually transmitted diseases:

Sexually Transmitted Diseases Caused by Bacteria

Bacteria are microscopic prokaryotic organisms. Not all bacteria are harmful, but a few that are harmful can cause deformities in our bodies. One of the modes of transmission of disease-causing bacteria includes sexual contact. Following are the most common sexually transmitted diseases caused by certain bacteria:

1. Gonorrhoea: This venereal infection is caused by the coccus bacteria, namely Neisseria gonorrhoeae.
Transmission: It affects both male and female genitals. It can also infect the throat and anus. It can be easily transmitted during vaginal intercourse but can also be transmitted during anal or oral sex.
Symptoms: The following symptoms have been come to know in the infected person:
i. In men, symptoms usually start within 2-10 days after infection. It may take a maximum of a month to appear. Intense inflammation in the penis that is followed by yellowish discharge of pus is the main symptom in males.

ii. Symptoms in females include an unusual discharge from the vagina, pain while urinating, abdominal pain, fever, etc. Symptoms start within 2-10 days after infection, but women are less likely to experience symptoms from gonorrhoea; hence the infection goes undetected for longer.
Treatment: Gonorrhea is a curable disease that can be treated with a single antibiotic injection of ceftriaxone along with a single dose of azithromycin or probenecid (1 gm) by mouth. However, resistant strains also respond well to norfloxacin and ciprofloxacin.

2. Syphilis: The causative agent of syphilis is a spirochaete bacterium, namely Treponema pallidum.
Transmission: It can be transmitted through direct contact with a syphilis sore during sexual intercourse. Sores occur mainly on the external genitalia, vagina, anus, or in the rectum. This disease can also be transmitted during close physical contact.
Symptoms: There are three distinct stages of the disease. After each stage, the symptoms become more instinctive, and the sufferer may fail to seek treatment. These stages can be tabulated as follows:

Treatment: Syphilis is easy to cure in its early stages. Syphilis can be easily treated and cured with intramuscular injection of penicillin. Other antibiotics available to treat syphilis are erythromycin, tetracycline, doxycycline, etc.

3. Chlamydiasis: It is caused by a bacterium Chlamydia trachomatis.
Transmission: Chlamydia can be transmitted during oral, vaginal, and anal sex. The disease can also be passed from an infected mother to her baby during vaginal parturition.
Symptoms: Symptoms usually start appearing after one to three weeks of exposure. Males and females show different symptoms. These are as follows:
i. Men might have a discharge from the urethra (penis) and also have a burning sensation during urination and itching around the head of the penis. Rarely could they have testicular swelling with pain.
ii. Females may complain of an abnormal vaginal discharge or a burning sensation while urinating. Other symptoms include lower abdominal discomfort, lower back pain, pain during sexual intercourse, bleeding in between menstrual periods.
Treatment: It can be easily treated and cured with antibiotics, such as tetracycline, doxycycline, azithromycin. Azithromycin is recommended during pregnancy.

Some other STDs caused by Bacteria:

Fig: Different Types of Bacteria Causes Sexually Transmitted Diseases

Learn About Reproductive Health Here

Sexually Transmitted Diseases Caused by Viruses

Viral infections are a threat to life as the diseases are mostly non-curable. Sexual contact is one of the modes of transmission of viral infection from a male partner to a female or vice versa. Viral diseases are fatal and are not curable. A few viral sexually transmitted diseases are discussed below:
1. Acquired Immunodeficiency Syndrome (AIDS): Acquired Immunodeficiency syndrome is caused by the infection from a retrovirus, known as Human Immunodeficiency Virus.
Transmission: AIDS can be transmitted by blood transfusion, hypodermic needles shared by addicts, during sexual intercourse, and from mother to baby during birth. This virus is not spread by casual physical contact such as hugging, sharing the same bathroom facilities.
Symptoms: Patients with AIDS have a depleted immune system and are very susceptible to opportunistic infections. HIV virus kills the T- cells. Common symptoms of AIDS include:
i. Fever
ii. Swollen lymph glands
iii. Weakness and weight loss
iv. Mouth sores
v. Diarrhoea
vi. High Blood Pressure

In severe conditions, the patient may develop pneumonia, Kaposi’s sarcoma (a skin cancer), lymphoma (cancer of the lymph system), tuberculosis. Although AIDS has a long incubation period, once it develops, there is a rapid decline in health. A commonly used diagnostic test for AIDS is Enzyme-Linked ImmunoSorbent Assay (ELISA).
Treatment and Prevention: There is no cure for AIDS. However, a variety of treatments is available that can delay the progression of the disease for many years and improve health. The following strategies are given a trail towards the inhibition of HIV:
i. Antiretroviral therapy is considered to be highly effective in reducing the number of HIV particles in the bloodstream. The HIV particles can be measured by a blood test called viral load. This can help the immune system to recover from HIV infection and improve T-cell counts.
ii. A recently introduced drug N-butyl deoxynojirimycin, however, holds some promise.
iii. Currently, AZT (azidothymidine) is used for the treatment of AIDS. Patients treated with AZT showed increased numbers of the circulating helper T-cells and increased immunological capacity.

2. Genital Warts: It is caused by Human Papilloma Virus (HPV). There are about 100 types of HPV. Approximately 30 types of HPV can live in and around the genital and anal areas. Most genital warts are caused by HPV-Type-6 and HPV-Type-11. Genital warts usually look like a small bump in the genital area. They are skin-coloured bumps that can be small or large, raised or flat.
Transmission: The virus can be transmitted through anal or vaginal intercourse. It can also be transmitted to the baby during birth.
Symptoms: Genital warts in males appear on the penis, scrotum, thighs, inside or around the anus. Genital warts in females appear inside and outside the vagina and anus, cervix. A few common symptoms of genital warts are as follows:
i. Vaginal discharge
ii. Itching, burning, and bleeding of infected genital areas.
Treatment and Prevention:
i. Smokers are more likely to have genital warts. Therefore avoiding smoking is a preventive measure against genital warts.
ii. Some recommended HPV treatments include imiquimod (Aldara), podophyllin and podofilox (Condylox), trichloroacetic acid (TCA).
iii. Warts can also be removed by burning through electric currents, laser therapy, injection of the drug interferon.
iv. The HPV vaccine can prevent two types of HPV that cause genital warts in 90% of the cases.

3. Genital Herpes: It is a sexually transmitted disease caused by Herpes Simplex Virus (HSV). This virus can be found in the vaginal fluid and semen.
Symptoms:
i. Blisters on the penis, scrotum, and buttocks, vagina are observed.
ii. Itching in the regions before the blisters appear.
iii. The blisters may become ulcerated and ooze fluid.
iv. Swollen lymph gland, headache, body ache, fever.
v. Babies that are born with genital herpes can develop blindness, brain damage.
Treatment and Prevention:
i. Antiviral drugs that help to heal the blisters can be taken.
ii. Cleaning the infected area with warm water can inhibit severe infection.

4. Hepatitis-B: It is a sexually transmitted disease caused by the Hepatitis virus.
Transmission: The disease can be transmitted during unprotected sex, through blood transfusion, through contaminated needles. It can also be transmitted to the baby during birth. The viruses are most likely to be found in the blood, semen, and vaginal fluid.
Symptoms: The infection can be acute or chronic. The symptoms of acute hepatitis are as follows:
i. Flu, diarrhoea, loss of weight, fever, body pain.
ii. Jaundice, dark urine, pale faeces, loss of appetite.
People who cannot fight off acute infections can go on to develop chronic hepatitis B which leads to a high risk of liver failure, liver cancer, liver cirrhosis.
Treatment and Prevention:
i. Acute hepatitis B can be overcome by home remedies and taking painkillers.
ii. Hepatitis B vaccine can be given as a preventive measure to children.

Fig: Different Types of Viruses Cause Sexually Transmitted Diseases

Sexually Transmitted Disease Caused by Protozoan

Trichomoniasis: It is caused by a flagellated protozoan called Trichomonas vaginalis. Infection is more common in women than men.

Fig: Trichomonas vaginalis

Transmission: The protozoan is passed from an infected person to an uninfected person during sex. The most infected part in women is the lower genital tract and urethra in males.
Symptoms:
The symptoms usually appear in women within 5-30 days of exposure. Most men with trichomoniasis do not have any symptoms.
i. Some men may have irritation inside the penis, mild discharge, burning after urination, or ejaculation.
ii. The symptoms in women include yellow-green vaginal discharge with a strong odour, itching, burning, and soreness of genitals.
Treatment and Prevention:
i. A latex male condom, when used consistently, can reduce the risk of trichomoniasis.
ii. Metronidazole can be prescribed, and the sexual partner must be treated simultaneously.

STDs Caused by Fungi & Parasite

Below we have tabulated the sexually transmitted diseases caused by Fungi and Parasite:

 Fig: Candida vaginitis & Public lice

Risk Factors Involved with STDs

Below we have provided some common risk factors associated with STDs:

1. Pelvic Inflammatory Disease (PID)
2. Abortion
3. Miscarriage
4. Reproductive Tract Cancer
5. Ectopic Pregnancies
6. Infertility
7. Eye inflammation
8. Heart disease
9. Arthritis
10. Pelvic pain

Sexual Health Practices

The following preventive measures should be taken in common to avoid the spread of all types of sexually transmitted diseases:
i. Avoid sex with an unknown partner, multiple partners, infected partner.
ii. Use of condoms during coitus.
iii. Avoid sexual contact while under the influence of alcohol.
iv. Vaccination against HIV, Hepatitis-B, HPV is necessary to reduce the chances of transmission of certain diseases.
v. Besides condoms, other barrier methods can be applied during sex.

Summary

We are known to have several infectious diseases that are caused by bacteria, viruses, protozoans, fungi, etc. These diseases can be transmitted from one person to another through several means. A number of disease-causing microbes inhabit in genital organs of an infected person. When such a person undergoes sexual activity with a healthy partner, they can transmit the disease-causing agent to their partner that leads to a particular disease. These diseases are called sexually transmitted diseases. Gonorrhoea, syphilis, chlamydia, hepatitis-B, AIDS, genital warts are a few commonly studied sexually transmitted diseases in humans. This article is a summarised study of all the diseases that transmit during coitus.

FAQs on Sexually Transmitted Diseases

Q.1. How easy is it to get STDs?
Ans: Sexually transmitted diseases can be most frequently transmitted through oral, anal, and vaginal sex.

Q.2. Who is more prone to STDs, males or females?
Ans: Females are more susceptible to sexually transmitted diseases because the larger vaginal surface is more exposed to sexual secretion.

Q.3. Can sexually transmitted diseases be cured?
Ans: The sexually transmitted diseases caused by viruses cannot be cured, while those caused by bacteria, fungi, protozoans, and parasites can be cured by drugs, medicines, and surgical methods.

Q.4. What causes AIDS?
Ans: AIDS is caused by a retrovirus named Human Immunodeficiency Virus.

Q.5. What are two of the deadliest STDs?
Ans: Acquired Immunodeficiency Syndrome (AIDS) and Hepatitis-B are the two deadliest sexually transmitted diseases because AIDS weakens the immune system, and Hepatitis-B attacks the liver that carries metabolic activities in the body.

Q.6. Name the protozoan which causes STDs in humans.
Ans: The STDs by Protozoans are caused by a flagellated protozoan called Trichomonas vaginalis.

Q.7. What are some of the preventive measures to avoid STDs?
Ans: Some of the preventive measures to avoid STDs are as follows:
i. Use of condoms during coitus.
ii. Avoid sexual contact while under the influence of alcohol.