Sexually transmitted diseases (STD, STIs).

More than 15 million acquired infections each year in the U.S.:an estimated 2.55 million new sexually transmitted infections.

Bacterial and protozoal sexually transmitted infections cause more than 1 million treatable, sexually transmitted diseases daily worldwide.

There has been a global resurgence of sexually transmitted infections.

The global incidence of bacterialy sexually transmitted infections, specifically chlamydia trachomatis, neisseria, gonorrhoeae and Treponema palladium are rising with 374 million infections estimated to occur annually.

Disproportionately affects racial and ethnic minorities, gay and bisexual men, and youth.

Adolescents and young adults are at highest risk for such infections because of behavioral and biologic factors.

Women are disproportionately burdened, by STI sequelae including:  pelvic inflammatory disease, chronic pain, infertility, ectopic pregnancy, increased risk of HIV accusation, and pregnancy and fetal complications.

There is an estimated one in five adults have an STI.

61% of the 1.1 million cases of chlamydia reported in 2018 in the US were among individuals age 15-24 years.

People with an STI (Sexually transmitted infection) are at a greater risk of transmitting HIV to others.

Among people without HIV, STIs increase rates of HIV acquisition.

STIs increase rates of infertility, chronic pelvic pain, atopic pregnancy, miscarriage, fetal death, and congenital neonatal infections.

Young patients more likely to engage in unprotected intercourse, multiple sexual partners and substance abuse in association with sexual activity.

Risk factors include women having sex during menses, coitarche, and being subject to coercive sex.

The use of alcohol, tobacco, marijuana are risk factors.

Use of oral contraceptives and having a new sexual partner are predictive for an incident HPV infection.

Incidence is increasing.

The high rates of sexually transmitted infections in the US contribute to chronic disease, cancer, infertility, adverse birth outcomes, and mortality with a substantial burden to population health.

The rates of gonorrhea, syphilis, and chlamydia infections have increased substantially in high income countries, with particular increases among men who have sex with men.

Estimated 1.4 million new cases of chlamydia and 350,000 cases of gonorrhea in 2014.

In 2022 reported rates of chlamydia were at 495 and of gonorrhea 194.4 per hundred thousand people, respectively.

Approximately 24,000 US women develop infertility related to sexually transmitted infections annually.

Sexually transmitted diseases (STDs), are infections that are commonly spread by sexual activity, especially vaginal intercourse, anal sex and oral sex.

Initially, STDs usually do not cause symptoms, resulting in a greater risk of passing the disease on to others.

The term sexually transmitted infection (STI) is generally preferred over sexually transmitted disease as it includes those who do not have symptomatic disease.

Symptoms and signs of disease include: vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain.

STDs can be transmitted to an infant before or during childbirth.

Some STDs may cause fertility problems.

1.1 billion reported cases other than HIV/AIDS, in 2015.

Deaths 108,000 other than HIV/AIDS, 2015.

More than 30 different agents-bacteria, viruses, and parasites can be transmitted through sexual activity.

About 500 million were infected with either syphilis, gonorrhea, chlamydia or trichomoniasis.

At least 530 million people have genital herpes and 290 million women have human papillomavirus.

Bacterial STDs include chlamydia, gonorrhea, and syphilis.

Viral STDs include genital herpes, HIV/AIDS, and genital warts.

Parasitic STDs include trichomoniasis.

Some sexually transmitted illnesses can be spread by non-sexual contact with donor tissue, blood, breastfeeding, or during childbirth.

The most effective way of preventing STDs is by not having sex.

Some vaccinations may also decrease risk of certain infections including hepatitis B and some types of HPV.

Safer sex practices such as use of condoms, having fewer sexual partners, and being in a monogamous relationship decreases the risk.

Circumcision in adult males may be effective to prevent some infections.

Most STIs are treatable or curable.

Of the most common infections, syphilis, gonorrhea, chlamydia, and trichomoniasis are curable STDs.

Herpes, hepatitis B, HIV/AIDS, and HPV STDs are treatable but not curable.

Resistance to certain antibiotics is develops among some organisms such as gonorrhea.

Sexually transmitted shigellosis has demonstrated significant antibiotic resistance.

Some untreated STIs can lead to infertility, chronic pain or death.

The presence of an STD in children may indicate sexual abuse.

Risk of transmission per unprotected sexual act with an infected person:

Performing oral sex on a man with an STD may result:

Throat chlamydia

Throat gonorrhea (25-30%)



Syphilis (1%)

Hepatitis B

HIV (0.01%)

Hepatitis C

Performing oral sex on a woman with a STD may result:



Throat gonorrhea

Throat chlamydia

Receiving oral sex from a man with a STD may result:






Receiving oral sex-woman-woman



Bacterial vaginosis


Vaginal sex-man





Hepatitis B




Mycoplasma hominis infection

Mycoplasma genitalium



Ureaplasma infection

Hepatitis C

Vaginal sex with a woman:





Hepatitis B




Mycoplasma hominis infection



Ureaplasma infection

Hepatitis C

Anal sex-insertive





Hepatitis B





Hepatitis C

Anal sex-receptive





Hepatitis B





Hepatitis C





Hepatitis A


Bacterial related STD:

Chancroid (Haemophilus ducreyi)

Chlamydia (Chlamydia trachomatis)

Gonorrhea (Neisseria gonorrhoeae)

Granuloma inguinale

Mycoplasma genitalium

Mycoplasma hominis

Syphilis (Treponema pallidum)

Ureaplasma infection




Viral hepatitis (Hepatitis B virus), saliva, venereal

Hepatitis C is rarely sexually transmittable.

Hepatitis A virus causes an acute, self-limiting hepatitis that is fulminating in  less than 0.5% of infections.
Hepatitis A virus  is transmitted by the fecal oral route through ingestion of contaminated food or water or by  direct contact with an infectious person.
Hepatitis A transmitted by men having sex with men.

Herpes simplex (Herpes simplex virus 1, 2) skin and mucosal, transmissible with or without visible blisters

HIV (Human Immunodeficiency Virus), venereal fluids, semen, breast milk, blood.

HPV (Human Papillomavirus), skin and mucosal contact.


Crab louse, colloquially known as “crabs” or “pubic lice” -Pediculosis pubis.


Trichomoniasis (Trichomonas vaginalis)

Sexually transmitted infections include:

Chlamydia- bacterium Chlamydia trachomatis.

Chlamydia symptoms may include abnormal vaginal discharge, burning during urination, and bleeding in between periods, although most women do not experience any symptoms.

Chlamydia symptoms in men include pain when urinating, and abnormal discharge from their penis.

Chlamydia can potentially lead to pelvic inflammatory disease (PID).

Chlamydia is curative with antibiotics.

The two most common forms of herpes are caused by infection with herpes simplex virus (HSV).

HSV-1 is typically acquired orally and causes cold sores.

HSV-2 is usually acquired during sexual contact and affects the genitals, however either strain may affect either site.

The virus affects the areas where it entered the body, occurring through kissing, vaginal intercourse, oral or anal sex.

Herpes virus is most infectious during times of visible symptoms.

Asymptomatic individuals can still spread the virus through skin contact.

The primary infection and related symptoms are usually the most severe, in the absence of antibodies.

After the initial attack, recurring attacks that are milder may occur.

No cure exists, but there are antiviral medications can treat symptoms and lower the risk of transmission.

HSV-1 can be transmitted to their partner genitally.

Human papillomavirus (HPV) is the most common STI in the United States.

More than 40 different strands of HPV exist and many do not cause any health problems.

In 90% of cases of HPV infection the body’s immune system clears the infection naturally within 2 years.

Some cases can lead to genital warts or cervical cancer and other HPV related cancers.

There are also two vaccines available for women (Cervarix and Gardasil) that protect against the types of HPV that cause cervical cancer.

HPV can be passed through genital-to-genital contact as well as during oral sex.

Gonorrhea bacterium live on moist mucous membranes in the urethra, vagina, rectum, mouth, throat, and eyes.

Gonorrhea infection can spread through contact with the penis, vagina, mouth or anus.

Symptoms of gonorrhea usually appear 2 to 5 days after contact with an infected partner.

In some cases men might not notice symptoms for up to a month after exposure.

Gonorrhea symptoms in men include burning and pain while urinating, increased urinary frequency, penile discharge-white, green, or yellow in color,red or swollen urethra, swollen or tender testicles, or sore throat.

Gonorrhea symptoms in women may include vaginal discharge, burning or itching while urinating, painful sexual intercourse, severe pain in lower abdomen with fallopian tube infection or fever.

Many women do not show any symptoms with gonorrhea.

Most cases of gonorrhea can be cured with antibiotics.

Clinical manifestations of syphilis include the ulceration of the uro-genital tract, mouth or rectum.

Trichomoniasis is caused by infection with a protozoan parasite called Trichomonas vaginalis.

While Trichomoniasis affects both women and men, symptoms are more common in women.

Trichomoniasis is treated with an antibiotic called metronidazole.

HIV is carried in body fluids, and is spread by sexual activity, along with

contact with infected blood, breast feeding, childbirth, and from mother to child during pregnancy.

The stages of HIV infection include primary infection, asymptomatic infection, symptomatic infection, and AIDS.

In the primary HIV infection stage, an individual will have flu like symptoms for about 2 weeks.

In the asymptomatic stage, symptoms usually disappear, and the patient can remain asymptomatic for years.

The symptomatic stage when the immune system is weakened, and has a low cell count of CD4+ T Cells, called AIDS.

Patients with AIDS are subject to opportunistic infections and die as a result.

Twenty-seven different viruses have been identified in semen.

Many STIs are more easily transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and less often, the mouth, throat, respiratory tract and eyes.

The membrane covering the head of the penis is a mucous membrane.

The penile membrane produces no mucus, similar to the lips of the mouth.

Mucous membranes allow certain pathogens into the body.

The amount of contact with infective sources varies with each pathogen but in all cases, a disease may result from even light contact from fluid carriers like venereal fluids onto a mucous membrane.

HIV can be transmitted from mother to child either during pregnancy or breastfeeding.

It is possible to be an asymptomatic carrier of sexually transmitted disease.

Sexually transmitted diseases in women often cause the serious condition of pelvic inflammatory disease.

STI tests may be useful for:

diagnostic test to determine the cause of symptoms or illness

as a screening test to detect asymptomatic or presymptomatic infections

as a check that prospective sexual partners are free of disease before they engage in sex without safer sex precautions

as a check prior to or during pregnancy,

to prevent harm to the baby

as a check after birth, to check that the baby has not caught an STI from the mother

to prevent the use of infected donated blood or organs

as part of the process of contact tracing from a known infected individual

as part of mass epidemiological surveillance

There is a window period after initial infection during which an STI test will be negative, and the infection may be transmissible.

Reducing STD risk include: vaccination, mutual monogamy, reducing the number of sexual partners, abstinence, avoiding contact of body parts or fluids which can lead to transfer with an infected partner.

Cybersex, phonesex or masturbation from a distance are methods of avoiding contact, and the proper use of condoms reduces contact and risk.

Some STIs, particularly certain persistent viruses may be impossible to detect.

Sexual prevention counseling for STIs is usually offered to all sexually active adolescents and to all adults who have received a diagnosis, have had an STI in the past year, or have multiple sex partners.

Vaccines are available for some viral STIs, such as Hepatitis A, Hepatitis B, and some types of HPV.

Vaccination before initiation of sexual contact is advised.

Condoms and female condoms only provide protection when used properly as a barrier.

Sexual transmission of HIV almost always involves the penis, as HIV cannot spread through unbroken skiN.

Proper male condom usage entails:

Not putting the condom on too tight,

too loose, avoiding inverting or spilling a condom once worn.

Female condom device consists of two rings: The larger ring fits over the cervix and the smaller ring remains outside the vagina, covering the vulva.

Cap and cervical diaphragm partially protect against STDs, but they do not protect against HIV.

CDC recommends sexually active women under the age of 25 and those over 25 at risk should be screened for chlamydia and gonorrhea yearly with

nucleic acid amplification tests.

Nucleic acid amplification tests can be done on either urine in both men and women, vaginal or cervical swabs in women, or urethral swabs in men.

Screening can be performed:

to assess the presence of infection and prevent tubal infertility in women

during the initial evaluation before infertility treatment

to identify HIV infection for men who have sex with men

for those who may have been exposed to hepatitis C

for HCV

Prophylactic antibiotics can be utilized in the case of rape.

Among women, the incidence of STI‘s was not significantly lower with doxycycline post exposure prophylaxis then with standard care (Stewart J).

Index cases and sexual partners should be treated for chlamydia or gonorrhea infections.

Sexual transmission of shigella manifests as  self-limiting gastroenteritis to severe, bloody dysentery.
Factors associated with sexually transmissible shigellosis  include direct oral anal contact, use of drugs to enhance sexual experiences, condom with sex, multiple sexual partners, use of sexual networking to meet partners, and attendance at six parties.
Sexual Transmission of enteric pathogens can be direct as through oral anal contact, or indirect through contact with physically contaminated fingers or objects.
The combined incidence of gonorrhea, chlamydia, and syphilis was lower by 2/3 with doxycycline post exposure prophylaxis than with standard care, supporting its use among MSM with recent bacterial STI’s.

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