Some sexually transmitted infections can spread through the use of unsterilized drug needles, from mother to baby during childbirth, or breast-feeding, and blood transfusions.
Sexually transmitted infections have been around for thousands of years. The genital areas are generally moist and warm environments - ideal for the growth of yeasts, viruses, and bacteria.
Microorganisms that exists on the skin or mucus membranes of the male or female genital area can be transmitted, as can organisms in semen, vaginal secretions, or blood during sexual intercourse.
Examples of sexually transmitted diseases include:
- crabs (pubic lice)
- genital herpes
- genital warts
- hepatitis B
- human immunodeficiency virus and acquired immunodeficiency syndrome (HIV and AIDS)
- human papillomavirus (HPV)
- trichomoniasis (parasitic infection)
- molluscum contagiosum
- pelvic inflammatory disease (PID)
- syphilis, gonorrhea
- trichomoniasis (trich)
Sexually transmitted infections are more easily passed on during unprotected sex - without using safer sex options (i.e., condoms, dams, sanitizing sex toys).
Some infections can be passed on via sexual contact but are not classed as sexually transmitted infections; for instance, meningitis can be passed on via sexual contact, but usually, people become infected for other reasons, so it is not classed as an STD.
The WHO (World Health Organization) estimates that, worldwide, there are more than 1 million new STDs acquired each day. People aged 15-24 acquire half of all new STDs, and 1 in 4 sexually active adolescent females has an STD, such as human papillomavirus or chlamydia. Compared with older adults, individuals aged 15-24 have a higher risk of getting STDs.
However, STI rates among seniors are increasing.
Common sexually transmitted infections
We take a look at some of the most common sexually transmitted infections below.
Also known as chlamydial infection, chlamydia is an STI caused by Chlamydia trachomatis (C. trachomatis), a bacterium that infects humans exclusively. Chlamydia is the most common infectious cause of genital and eye diseases globally - it is also the leading bacterial STI.
According to the CDC (Centers for Disease Control and Prevention), in 2015, nearly 3 percent of girls aged 15-19 had chlamydia.
Women with chlamydia do not usually have signs or symptoms. If there are any, they are usually non-specific and may include:
- a change in vaginal discharge
- mild lower abdominal pain
If chlamydia is left untreated, it may lead to the following signs and symptoms:
- pelvic pain
- painful sexual intercourse, either intermittently or all the time
- bleeding between menstrual periods
Chancroid is also known as soft chancre and ulcus molle. It is a bacterial infection caused by fastidious gram-negative streptobacillus Haemophilus ducreyi and is characterized by painful sores on the genitals. It is only spread through sexual contact.
Infection rates are very low in rich countries; it is more common in developing nations, especially among commercial sex workers and some low socioeconomic groups. This is due to the lack of access to healthcare services, the stigma attached to seeking help, a lack of sexual health awareness, and other factors.
In 2015, just 11 cases of chancroid were reported in the United States. Chancroid increases the risk of contracting HIV, and HIV increases the risk of contracting chancroid.
Within 1 day to 2 weeks after becoming infected, the patient develops a bump that turns into an ulcer within a day. The ulcer can be from 1/8 of an inch to 2 inches across, it is very painful, may have well defined, undermined borders, and a yellowish-gray material at its base. If the base is grazed, it will typically bleed. In some cases, the lymph nodes swell and become painful (lymphadenopathy).
Women often have at least four ulcers, while men usually have just one. Males tend to have fewer and less severe symptoms. The ulcers typically appear at the groove at the back of the glans penis (coronal sulcus) in uncircumcised males, or, in females, the labia minora (small inner folds of the vulva) or fourchette (thin fold of skin at the back of the vulva).
Chancroid is treated with a 7-day course of erythromycin, a single oral dose of azithromycin, or a single dose of ceftriaxone.
Crabs (pubic lice)
Pthiriasis (pubic lice manifestations) are primarily spread through sexual contact. Pets do not play any part in the transmission of human lice. The lice attach to the pubic hair, and may also be sometimes found in the armpits, mustache, beard, eyelashes, and eyebrows. They feed on human blood.
The common term "crabs" comes from the appearance of the lice, with their crab-like claws and body shape.
This STI is caused by the herpes simplex virus (HSV). The virus affects the skin, cervix, genitals, and some other parts of the body. There are two types:
- HSVp1, also known as herpes type 1
- HSV-2, also known as herpes type 2
Herpes is a long-term (chronic) condition. A significant number of infected individuals never show any symptoms and do not know about their herpes status.
HSV is easily transmissible from human-to-human by direct contact. Most commonly, transmission of type 2 HSV occurs through vaginal, oral, or anal sex. Type 1 is more commonly transmitted from shared straws, utensils, etc. In most cases, the virus remains dormant after entering a human being, in other words, there are no symptoms.
The signs and symptoms associated with genital herpes, if they do appear, may include:
- blisters and ulceration on the cervix
- vaginal discharge
- pain on urinating
- generally feeling unwell (malaise)
- cold sores around the mouth - for type 1 HSV
Also, there may be red blisters - these can be painful, especially after they burst and leave ulcers on the external genital area, rectum, thighs, and buttocks.
This STD is caused by the hepatitis B virus (HBV). It is transmitted through contact with infected semen, blood, and some other body fluids. A person can become infected by having unprotected sex, using an unsterilized syringe, being accidentally pricked by a sharp object, drinking infected breast milk, or being bitten by an infected person.
The patient's liver swells, and they can suffer serious liver damage as a result of the infection, which can eventually lead to cancer. In some cases, the disease can become chronic. Blood donation centers always check to make sure the donor's blood is free of the hepatitis B virus.
HIV and AIDS
HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome). Put simply, HIV is the virus while AIDS is the illness/disease. When a person has AIDS, their immune system is altered, and they become much more vulnerable to infections and diseases. As the disease progresses, this susceptibility worsens.
HIV exists in the body fluids of a person who has HIV, such as semen, blood, breast milk, and vaginal fluids. HIV can be transmitted through blood-to-blood contact, which may occur during sexual contact (vaginal, oral, or anal sex), blood transfusions, breast-feeding, childbirth, and the sharing of infected needles.
Human Papillomavirus (HPV)
Most people with an HPV infection have no symptoms.
Human Papillomavirus is a name for a group of viruses that affect the skin, as well as the moist membranes that line the body, such as the throat, cervix, anus, and mouth.
There are over 100 types of HPV, of which, about 40 can affect the genital areas; these types may also infect the mouth and throat.
The ones that affect the genital area are known as genital human papillomavirus.
HPV infection can lead to:
- The abnormal growth and alteration of cells within the cervix, which significantly increases the risk of developing cancer of the cervix.
- Genital warts, the most common STI in the majority of developed nations.
The majority of infected individuals have no symptoms and are unaware.
HPV is most commonly transmitted through vaginal or anal sex. However, oral sex and genital-to-genital contact (without penetration) are also avenues for transmission. Infected people with no signs and symptoms can infect others.
A pregnant mother who has HPV can transmit the virus to her baby during childbirth, although this is very rare.
According to the CDC, most sexually active Americans will be infected with one type of HPV at some time in their lives.
The best protection from HPV infection is to be vaccinated.
Trichomoniasis is a common sexually transmitted disease that can affect both males and females. However, women are more likely to experience symptoms. The infection is caused by a single-celled protozoan parasite, Trichomonas vaginalis.
For women, the most common site of infection is the vagina, while for men it is the urethra (urine canal). Transmission may occur either by penis-to-vagina sexual intercourse or vulva-to-vulva contact.
While women may be infected from either male or female sexual partners, men nearly always become infected from having sex with women (not men).
Signs and symptoms of trichomoniasis include:
- vaginal odor
- vaginal discharge
- pain or discomfort during sexual intercourse
- pain when urinating
A woman with trichomoniasis is more likely to become HIV infected if she is exposed to the virus. A woman with trichomoniasis and HIV is also more likely to pass the HIV virus onto other sexual partners.
Molluscum contagiosum is a contagious skin infection caused by a virus. There are four types: MCV-1 (most common), MCV-2 (most commonly sexually transmitted one), MCV-3, and MCV-4. When it infects young children, it is not considered an STI.
Signs and symptoms include small, round bumps and indents on the skin. If left untreated, the bumps usually go away, but this can take up to 2 years. A doctor can remove the bumps with chemicals, an electrical current, or by freezing them. There are some prescription medicines that will eventually get rid of the growths.
Scabies is a contagious skin condition caused by Sarcoptes scabiei, a tiny mite. They burrow into the skin and lay their eggs. The patient develops a skin rash and experiences intense itchiness. People with scabies are often unaware of their condition for several weeks after initial infection, which means scabies infestations spread rapidly.
Some experts believe scabies is caused by poor living conditions and a lack of personal hygiene - however, there is no scientific proof of this.
Scabies is most commonly transmitted through close body contact, such as holding hands for a long time or sexual intercourse. Hugging a person who has scabies or simply shaking hands with them is unlikely to lead to transmission.
The scabies mite cannot jump or fly. However, it can survive for 1-2 days after leaving the human body - this means that sharing clothing or bedding with an infected person raises the risk of infection. However, prolonged physical contact, as may occur during sexual intercourse, is the most common route of transmission.
Signs and symptoms of scabies may not become apparent for several weeks after initial infection, and may include:
- A skin rash - small red spots, known as burrow marks; they look like tiny insect bites. Some people may think it is eczema.
- Intense itching, which gets worse at night or after taking a hot shower.
- The burrow marks, which typically appear as a small line of at least four tiny spots, appear on the elbows, wrists, around the nipples (in women), near the genitals (in men), and in between the toes and fingers.
- After scratching the rash, the area can become inflamed, and crusty sores may develop.
- Less commonly, the rash may appear on the buttocks, ankles, axillae (armpits), genitalia (in women), groin, the inside of the elbow, scalp, neck, face, head, shoulders, waist, soles of the feet, lower leg, and knees.
Syphilis is the result of infection by Treponema pallidum, a bacterium. It is transmitted by sexual contact - the infected person has a syphilis lesion. An infected mother can pass on this STI to her baby during pregnancy, which can result in stillbirth or serious birth defects. An infected person, when exposed to HIV, has a higher risk of becoming HIV-positive.
There is a 9-90-day incubation period after initial infection - average time 21 days, before the initial signs and symptoms of the disease emerge. Each syphilis stage has characteristic signs and symptoms. Some infected people have no signs, while for others they may be mild. In some cases, even if signs and symptoms go away, the bacterium is still there and can cause serious health problems later on.
Neisseria gonorrhoeae bacteria.
Also known as the clap or the drip, this sexually transmitted bacterial infection usually attacks the mucous membranes.
Gonorrhea is the second most common STD in the U.S., after Chlamydia.
The bacterium, which is highly contagious, resides in the warm and moist cavities of the body.
The majority of infected women show no signs or symptoms. If left untreated, females may develop pelvic inflammatory disease; males may develop inflammation of the prostate gland, urethra, or epididymis.
The disease is caused by Neisseria gonorrhoeae. The bacteria can survive in the vagina, penis, mouth, rectum, or eye; it can be transmitted during a variety of sexual contacts.
As soon as a person is infected, they risk spreading the bacteria to other parts of their body - somebody may inadvertently rub their eye and spread the infection; this prolongs the treatment period. A mother can pass the infection on to her baby during childbirth.
Signs and symptoms of gonorrhea may appear from 2-10 days after initial infection, in some cases, it may take 30 days. Some patients have such mild symptoms that their infection is mistaken for something else, such as a yeast infection.
Males may have the following signs and symptoms:
- burning during urination
- testicular pain and/or swelling
- a green, white, or yellow discharge from the penis
Women are less likely to show symptoms, but if they do, they may include:
- spotting after sexual intercourse
- swelling of the vulva (vulvitis)
- irregular bleeding (between periods)
- pink eye (conjunctivitis)
- pain in the pelvic area
- burning or pain during urination
If the rectum becomes infected, there may be anal itching, painful bowel movements, and sometimes discharge. When transmission occurred from oral sex, there may be burning sensation in the throat and swollen glands.
Prevention of sexually transmitted infections
Have "safe sex" - for each sexual act, use a new latex condom, whether it be oral, vaginal, or anal sex. Avoid using an oil-based lubricant, such as petroleum jelly when using a latex condom. Non-barrier forms of contraception, such as oral contraceptives or intrauterine devices, do nothing to protect people from sexually transmitted infections.
Abstain - abstaining from any sexual act is probably the most effective way to avoid becoming infected with an STD.
Be faithful to one uninfected partner - be in a long-term relationship with a person who is not infected, and remain faithful.
Vaccinations - there are vaccinations that can protect from eventually developing some types of cancer caused by two STIs - the HPV (human papillomavirus) and Hepatitis B vaccines.
Check for infections - before sexual intercourse with a new partner, check that the partner and yourself have no STIs.
Drink alcohol in moderation - people who are drunk are more likely to engage in risky behavior. Avoid using some recreational drugs, which may also affect judgment.
Explain you want safe sex - before engaging in any sexual act with a new partner, make it clear that you would only consider safe sex.
Education - parents, schools, and society in general need to teach children about the importance of safe sex, and explain how to prevent becoming infected with an STI. Education should also include information relevant to the LGBTQ (lesbian, gay, bisexual, transgender, queer/questioning) population.