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Sexually Transmitted Infections (STIs),

known as Sexually Transmitted Diseases (STDs) or Venereal Diseases (VD) are diseases that are passed on from one person to another through sexual contact, and sometimes by genital contact - the infection can be passed on via vaginal intercourse, oral sex, and anal sex.

  • Some sexually transmitted infections can spread through the use of unsterilized IV drug needles, from mother to baby during childbirth or breastfeeding, and blood transfusions.

  • Sexually transmitted infections have been around for thousands of years.

  • 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.

  • The term "venereal disease" is much less used today, while "sexually transmitted diseases" is slowly giving way to "sexually transmitted infections", because the last term has a broader range of meaning - a person can pass on the infection without having a disease (they do not have to be ill to infect other people).

  • The genital areas are generally moist and warm environments - ideal for the proliferation of yeasts, viruses and bacteria.

Examples of sexually transmitted infections (STIs) include:

Sexually transmitted infections are more easily passed on during unprotected sex - without using a condom.

Some infections can be passed on via sexual contact, but are not classed as sexually transmitted infections, because sexual contact is not the primary vector for the pathogens that cause the infections - an example is meningitis, it can be passed on via sexual contact, but usually people become infected for other reasons.

The WHO (World Health Organization) estimated over ten years ago that over 1 million people each day became infected with a sexually transmitted infection - most experts believe the figure is considerably higher today. The majority of these new infections occur in young adults aged up to 25 years, while approximately one third occur among individuals younger than 20 years of age. Globally, girls aged 14 to 19 are almost twice as susceptible to STIs than boys of the same age.

  • Chlamydia

  • Chancroid

  • Crabs (Pubic Lice)

  • Genital herpes

  • Genital warts

  • Hepatitis B


  • Human Papillomavirus (HPV)

  • Trichomoniasis (parasitic infection)

  • Molluscum Contagiosum

  • Pelvic Inflammatory Disease (PID)

  • Scabies

  • Syphilis

  • Syphilis, gonorrhea

  • Trichomoniasis (Trich)

  • Yeast infections

Common sexually transmitted infections

We take a look at some of the most common sexually transmitted infections below.


There are nearly 3 million reported cases of Chlamydia in the US each year (American Sexual Health Association).

Also known as chamydial 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), 6.8% of girls aged 14 to 19 years have Chlamydia today.

Women with Chlamydia do not usually have signs or symptoms. If there are any, they are usually non-specific and may include:

  • Cystitis

  • A change in vaginal discharge

  • Mild lower abdominal pain


If the 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


Also known as soft chancre and ulcus molle. A bacterial infection caused by fastidious Gram-negative streptobacillus Haemophilus ducreyi, and is characterized by painful sores on the genitalia. It is spread solely 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.

The average prevalence in the US, UK, Australia, France and Canada is approximately 1 case in every 2 million people. It is a risk factor for contracting HIV, due to their shared-risk exposure; also, one infection facilitates the transmission of the other

Within one day to two 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 in to 2 inches across, it is very painful, may have well defined, undermined borders, has a yellowish-gray material at its base. If the base is grazed it will typically bleed. In about 30% to 60% of 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 the labia minora or fourchette in females.

Chancroid is treated with a seven day course of Erythromycin, a single oral 1 gram dose of Azithromycin, or a single IM 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, moustache, beard, eyelashes, and eyebrows. They feed on human blood.

The vernacular "crabs" comes from the appearance of the lice, with their crab-like claws and body shape.

Genital herpes

This STI is caused by the herpes simples virus (HSV). The virus affects the skin, cervix, genitals, and some other parts of the body. There are two types:

  • HSV-1, 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 occurs through vaginal, oral or anal sex. In most cases, the virus remains dormant after entering a human being.

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

  • Fever

  • Generally feeling unwell (malaise)

  • Cold sores around the mouth

  • Red blisters - these can be painful, especially after they burst and leave ulcers on the external genital area, rectum, thighs and buttocks.

Key things you need to know

 Hepatitis B

This STI is caused by the Hepatitis B Virus (HBV). It is transmitted via 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 he/she 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 (Human Immunodeficiency Virus) is the virus that causes AIDS (Acquired Immune Deficiency Syndrome or Acquired Immunodeficiency 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 infected people, 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, breastfeeding, childbirth, and the sharing of infected needles.

Human Papillomavirus (HPV)

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 of males and females; 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 can significantly increase 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.

The HPV vaccine prevents HPV infection

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.

An infected pregnant mother can transmit the virus to her baby during childbirth, although this is very rare.

According to the CDC, half of all Americans who are sexually active will become infected with genital human HPV some time in their lives.

The best way to be protect from HPV infection is to be vaccinated.


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. Sufferers 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 infected people or simply shaking hands with them is unlikely to lead to transmission.

The scabies mite cannot jump or fly. However, it can survive for one or two 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.

  • Upon scratching areas of skin where the rash is, 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 to 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.


Also known as the clap or the drip, this sexually transmitted bacterial infection usually attacks the mucous membranes. Gonorrhea is the second most common STI in the USA, 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, while males may develop inflammation of the prostate gland, urethra, or epididymis.

The disease is caused by the proliferation of Neisseria gonorrhoeae. The disease can survive in the vagina, penis, mouth, rectum, or eye; it can be transmitted in a variety of sexual contacts.

As soon as a person is infected, he/she risks 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 two to ten 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 more likely to show no symptoms, 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 do nothing to protect people from sexually transmitted infections. Examples include oral contraceptives or intrauterine devices.

Consult a doctor for medical advice or visit us at PEOPLE CARE INSTITUTE for more information


Note: The information you see here is general and describes what usually happens with a medical condition, but doesn't apply to everyone. This information IS NOT  a substitute for professional medical advice, so please  make sure to contact a healthcare provider if you have a medical problem. 

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