Some common presentations include:

• Urogenital

Presentation can be simply that the genitals are red and sore to sometimes painful and swollen. There may be a burning sensation in urinating and a white or coloured discharge may be found from the vagina or penis. There may be sores, ulcers, blisters or warts.

• Systemic

If the infection has spread, there may be systemic effects [3]. The infective agent may affect the heart, kidneys, brain, eyes, joints, etc.

• Inguinal Lymphadenopathy

  Genital ulcers may be single or multiple and may be associated with inguinal or femoral lymphadenopathy. [web.archive.org]

  Primary inguinal syndrome- Begins 2-6 weeks after exposure as a painful inguinal or femoral lymphadenopathy that is usually unilateral. [atsu.edu]

  The most common clinical manifestation of LGV among heterosexuals is tender inguinal and/or femoral lymphadenopathy that is typically unilateral. A self-limited genital ulcer or papule sometimes occurs at the site of inoculation. [cdc.gov]

• Weight Loss

  You might also have weight loss or diarrhea. The only way to know with certainty that you have contracted AIDS is through a test that your doctor can administer. AIDS slowly destroys the immune system. [navicenthealth.org]

  If symptoms are present, they may include: Bumps, sores, or warts near the mouth, anus, penis, or vagina Swelling or redness near the penis or vagina Skin rash Painful urination Weight loss, loose stools, night sweats Aches, pains, fever, and chills Yellowing [my.clevelandclinic.org]

  Weight loss, loose stools, night sweats. Aches, pains, fever, and chills. Yellowing of the skin ( jaundice ). Discharge from the penis or vagina. Vaginal discharge may have an odor. Bleeding from the vagina other than during a monthly period. [webmd.com]

  Other symptoms you may have can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue (feeling very tired). [cdc.gov]

  Other symptoms of secondary syphilis include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The symptoms of secondary syphilis will go away with or without treatment. [web.archive.org]

• Chills

  If symptoms are present, they may include: Bumps, sores, or warts near the mouth, anus, penis, or vagina Swelling or redness near the penis or vagina Skin rash Painful urination Weight loss, loose stools, night sweats Aches, pains, fever, and chills Yellowing [my.clevelandclinic.org]

  […] that symptoms are present, they may include the following: Bumps, sores, or warts near the mouth, anus, penis, or vagina Swelling or redness near the penis or vagina Rash Painful urination Weight loss Loose stools Night sweats Aches, pains, fever, and chills [navicenthealth.org]

  Aches, pains, fever, and chills. Yellowing of the skin ( jaundice ). Discharge from the penis or vagina. Vaginal discharge may have an odor. Bleeding from the vagina other than during a monthly period. Painful sex. [webmd.com]

  HIV Symptoms Flu-like symptoms 1 to 2 months after first infection, including like swollen lymph nodes, fever, and headaches Chills Rash Night sweats Muscle Aches Sore throat Swollen lymph nodes Mouth ulcers AIDS Symptoms Rapid weight loss Recurring fever [onhealth.com]

  The common symptoms experienced by STD sufferers include: Bumps and sores near the vagina, penis, anus, or mouth Warts Swelling Redness Rashes Painful urination Loose stools Weight loss Aches and pains Fever Chills Jaundice Vaginal discharge that’s different [docdoc.com.sg]

• Lymphadenopathy

  Inguinal lymphadenopathy is present in about 50% of the patients with genital ulcer diseases. Genital herpes typically presents with multiple, shallow ulcers and bilateral lymphadenopathy. [web.archive.org]

  Three were diagnosed in 2009 in HIV-negative heterosexuals patients that presented the classical genito-ulcerative form with lymphadenopathy. [ncbi.nlm.nih.gov]

  Regional lymphadenopathy adjacent to the chancre may develop during primary syphilis. The swollen lymph nodes are firm, nonsuppurative. Lymphadenopathy may persist for months, despite healing of the chancre. [atsu.edu]

  Primary genital HSV infection can range from asymptomatic infection to a severe syndrome with multiple painful genital ulcers, fevers, dysuria, and tender lymphadenopathy. [clinicaladvisor.com]

  Look for lumps, swelling, lymphadenopathy, abnormal discharge, sores, ulcers, tears and scars around the genitals and in between the skin folds of the vulva. Speculum examination for: Vaginal discharge and redness of the vaginal walls (vaginitis). [patient.info]

• Rigor

  Therefore, they are not always the same as official national estimates produced using alternate, potentially equally rigorous methods, nor necessarily endorsed by specific Member States. [web.archive.org]

  "Safe sex" – the mantra of the 1980s following the outbreak of the HIV pandemic – is no longer practiced as rigorously as it was back then. [dw.com]

  However, these competing hypotheses have never been rigorously tested, despite their importance for understanding the global spread and vaccine-relevant genetic diversity of HIV-1. [doi.org]

  […] a negative effect on society: "The whole of human history does not contain a single instance of a group becoming civilized unless it has been absolutely monogamous, nor is there any example of a group retaining its culture after it has adopted less rigorous [en.wikipedia.org]

• Severe Pain

  You will need a follow-up visit 7 days after if your symptoms include joint pain, skin rash, or more severe pelvic or abdomen pain. Tests will be done to make sure the infection is gone. [medlineplus.gov]

  Symptoms in women may include vaginal discharge, burning or itching while urinating, painful sexual intercourse, severe pain in lower abdomen (if infection spreads to fallopian tubes), or fever (if infection spreads to fallopian tubes); however, many [en.wikipedia.org]

  Emergency testing for torsion might be indicated when the onset of pain is sudden, pain is severe, or the test results available during the initial examination do not support a diagnosis of urethritis or urinary-tract infection. [cdc.gov]

• Chronic Diarrhea

  As the virus continues to multiply and destroy immune cells, you may develop mild infections or chronic signs and symptoms such as: Swollen lymph nodes — often one of the first signs of HIV infection Diarrhea Weight loss Fever Cough and shortness of breath [mayoclinic.org]

  Symptoms That Suggest Sexually Transmitted Infections May Include: HIV/AIDS Headaches Difficulty swallowing Fever Night sweats Fatigue/weakness Appetite loss Weight loss Chronic diarrhea Nausea/vomiting Itchy, rashy skin/skin lesions Chronic coughing [healthychildren.org]

• Failure to Thrive

  As well they may experience severe forms of bacterial infections such as: conjunctivitis (pink eye) ear infections tonsillitis as well as delayed development failure to thrive AIDS sufferers commonly develop various cancers caused by viruses, such as: [herpes-coldsores.com]

• Myalgia

  During the acute stage there may be systemic manifestations include; fever, chills, headache, anorexia, myalgias, arthralgias, hypergammaglobulinemia and splenomegaly. [atsu.edu]

  The Jarisch-Herxheimer reaction is an acute febrile reaction frequently accompanied by headache, myalgia, and other symptoms that usually occur within the first 24 hours after any therapy for syphilis. [cdc.gov]

• Burning Sensation

  There may be a burning sensation in urinating and a white or coloured discharge may be found from the vagina or penis. There may be sores, ulcers, blisters or warts. Systemic If the infection has spread, there may be systemic effects. [symptoma.com]

  Symptoms in men include Discharge from your penis A burning sensation when urinating Burning or itching around the opening of your penis Pain and swelling in one or both testicles (although this is less common) If the chlamydia infects the rectum (in [nlm.nih.gov]

  Symptoms may include painful blisters or open sores in the genital area, which may be preceded by a tingling or burning sensation in the area. [stanfordchildrens.org]

  Men: Penile discharge Mild to severe burning sensation when urinating Can progress to epididymitis Women: Painful or burning sensation when urinating and/or yellow or bloody vaginal discharge Abdominal pain Bleeding between menstrual periods Vomiting [healthychildren.org]

• Paresthesia

  Pain and paresthesias around the outbreak site precede the appearance of lesions by 12 to 48 hours. The hallmark of genital herpes consists of grouped vesicles or pustules that lead to shallow ulcers. [web.archive.org]

  Preataxic patient experience lightning like pain radiating from the gluteal region to the heel or foot paresthesia of the soles of the feet and they mention walking feels like walking on carpet or wood. [atsu.edu]

• Vaginal Discharge

  Vaginal discharge Normal vagina and cervix during a medical speculum exam demonstrating IUD strings at the opening of the cervix and normal milky white vaginal discharge on the vaginal walls, cervix, and pooled in vaginal fornix. [en.wikipedia.org]

  Considering more than 20 studies of lower tract inflammation, M. genitalium has been positively associated with urethritis, vaginal discharge, and microscopic signs of cervicitis and/or mucopurulent cervical discharge in seven of 14 studies. [ncbi.nlm.nih.gov]

  and vaginal discharge. [dx.doi.org]

• Salpingitis

  PID can manifest as endometritis, salpingitis, adnexitis, tubo-ovarian abscess, pelvic peritonitis (figure 46) or perihepatitis. The most common manifestation of PID is salpingitis, and these terms are used synonymously in the literature. [web.archive.org]

  Observations concerning the microbial etiology of acute salpingitis. Am J Obstet Gynecol 1994; 170 (4) 1008-1014, discussion 1014–1017 84 Jossens MO, Schachter J, Sweet RL. [dx.doi.org]

  Detection of novel organisms associated with salpingitis, by use of 16S rDNA polymerase chain reaction. J Infect Dis. 2004; 190 (12):2109–2120. [ PubMed ] [ Google Scholar ] 89. Sweet RL, Gibbs RS. [ncbi.nlm.nih.gov]

• Dysuria

  Primary genital HSV infection can range from asymptomatic infection to a severe syndrome with multiple painful genital ulcers, fevers, dysuria, and tender lymphadenopathy. [clinicaladvisor.com]

  Men infected with M. genitalium frequently present with dysuria, while women may present with or without urogenital symptoms. [doi.org]

  Vaginitis presents with an increase in the amount, odor or color of discharge and may be accompanied by itching, dysuria, dyspareunia, edema or irritation of the vulva. [web.archive.org]

  Symptoms, if present, include dysuria; urethral pruritis; and mucoid, mucopurulent, or purulent discharge. Signs of urethral discharge on examination can also be present in persons without symptoms. [cdc.gov]

  Initial manifestations include local pain, tenderness, itching sensation, and dysuria. The pain associated with dysuria in females is described as more of an “external pain”. [atsu.edu]

• Dyspareunia

  Vaginitis presents with an increase in the amount, odor or color of discharge and may be accompanied by itching, dysuria, dyspareunia, edema or irritation of the vulva. [web.archive.org]

  A review of systems should emphasize symptoms of thyroid disease, pelvic or abdominal pain, dyspareunia, galactorrhea, and hirsutism ( 101 ). [cdc.gov]

• Burning Micturition

  Some of these symptoms include: red, swollen and painful genitals, discharge from penis or vagina, ulcers or warts, burning micturition, etc. [symptoma.com]

The work up includes blood sampling for culture and sensitivity. A swab sample of fluids may be collected from the throat, cervix, vaginal canal and/or rectum in females and throat, penile urethra and/or rectum in males.

Laboratory Tests Results

• Gram staining: Gram staining may be done to check for the organism involved.
• PCR: A Polymerase Chain Reaction test maybe done for more accurate results.
• C/S: Culture and sensitivity of either blood samples, urine or swab samples may be done for accurate results.

If the test results come positive for one STD, treatment is immediately started. Other STDs are also checked.

The exact treatment varies depending upon the type of STD it is. But generally, treatment is either oral or parenterally administered antibiotics. The common regime used these days for gonorrhea and chlamydia infection is Ceftriaxone, Azithromycin and Doxycycline given in a combination to prevent reoccurrence.

STDs, if treated adequately, have a good prognosis, unless it's an incurable one like AIDS. Symptoms are mild at first and if the diagnosis is made on time, and appropriate antibiotics are administered, symptoms regress completely.

However, if for example primary syphilis is left untreated and it progresses to tertiary syphilis, it may cause irreversible damage.

Complications

If left untreated, an STD may lead to:

Males

• Septic arthritis
• Epidydimisitis
• Oligospermia
• Sterility
• Systemic defects involving the heart, brain and joints

Females

• Pelvic Inflammatory Disease
• Septic arthritis
• Septic abortion
• Infertility
• Ectopic pregnancies
• Systemic defects involving the heart, brain and joints

A sexually transmitted disease is caused by microorganisms which are transferred from an infected individual to his/her sexual partner during intercourse.

Mode of Transmission:

• Sexual Transmission

This is the most common mode of transmission. An individual may knowingly or unknowingly transmit the pathogen to his or her sexual partner by either oral, vaginal or anal sex. Depending upon the kind of intercourse performed, the microbes may start an infection in that area. For example, anal sex leads to development of disease primarily in the rectum, oral sex leads to infection in the throat, etc. [10].

• Intravenous Drug Abuse

Drug addicts often share needles and syringes with each other and this unsanitary and unchecked misuse is also a leading cause of transferring infections. Of such, HIV is a very commonly transferred disease.

• Mother to child

Some STDs can be transferred from an infected mother to her child during childbirth when the baby passes through the infected birth canal. STDs like Gonorrhea can be transferred from mother to child during cord clamping as a fluid exchange may occur.

• Other

Other causes include exposure to a pathogen on an open wound, administration of donor blood that is contaminated with a microbe, etc.

Incidence

Studies conducted by the Centres of Disease Control reveal that there are 19.7 million new cases of sexually transmitted diseases occurring in the United States annually [1]. It is estimated that one in every 4 teenagers contracts an STI and/or STD each year.

Sex

Most STDs, though not all, are more common in women than in men. The exact prevalence varies with different types of STDs. Female to male ratios of some common STDs are mentioned below:

• Chlamydia infection occurs in 592.2 per 100,000 people in females as compared to just 219.3 per 100,000 people in males. 
• Gonorrhea occurs in 105.5 per 100,000 people in females as compared to just 91.9 per 100,000 people in males. 
• But in the case of Syphilis, the rate among men is much higher. The ratio being almost 1:7 in the US in 2009.

Age

STDs can occur at any age, ranging from in babies (in the case of gonorrhea which can be contracted by an infant during birth from an infected mother) to old age. But it is most commonly found in young people between 15-24 years of age.

Race

Most STDs are more prevalent in people belonging to the African-American race than in white people.

Most Prevalent STDs

• The most common STD in the world is Chlamydia infection.
• The second most common STD in the world is Gonorrhea.

When an affected individual has unprotected sexual intercourse with his/her sexual partner, the bacteria or other microbes enter into the genital tract. The primary area of infection depends upon the type of intercourse performed, for example, vaginal intercourse may cause the primary area of infection to be the vagina and cervix, anal intercourse leads to a primary infection in the rectum, oral sex leads to a throat infection, etc. [9].

Once a primary infection has been established, symptoms may or may not appear. The microbes may move from the genital tract to the lymphatic system and then enter the blood stream. If that happens, systemic effects appear [7].

Common STDs and Causative Agents:

Bacterial

• Chlamydia infection is caused by a bacterium called Chlamydia trachomatis.
• Gonorhea is caused by Neisseria gonorrhea.
• Syphilis is caused by Treponema pallidum.
• Chancroid by Hemophilius ducreyi.

Viral

• Human immunodeficiency virus (HIV) causes AIDS.
• Human papillomavirus (HPV) causes most commonly genital warts.
• Herpes simplex virus type 2 causes herpes [4].

Protozoal

• Trichomoniasis caused by Trichomona vaginalis.

Fungal

• Candidiasis is caused by Yeast.

Common Symptoms:

• Red, swollen genitals
• Pain and burning sensation during micturation
• Greenish-yellow or white coloured penile/vaginal discharge
• Spotting after sexual intercourse
• Bleeding between menstrual periods
• Lower abdominal and pelvic pain, sometimes mimicking pain of PID
• Ulcers on and around genitals
• Warts or blisters on and around genitals 
• Sore throat (oral sex)
• Swollen glands in the throat (oral sex)
• Pain in defecation (anal sex)
• Itching and general discomfort around anus and genitals

STDs can be easily prevented. Preventive measures include:

• Using latex condoms during intercourse [5]
• Getting checked for STDs, at least once a year if sexually active
• Having only one sexual partner
• No drug abuse
• Using syringes, donated blood, etc from reliable and well sanitised centres

Sexually transmitted diseases (STD) are a leading cause of hospital check ups in the world. Studied under a separate branch of science called Venereology, sexually transmitted diseases can be caused by a number of pathogens resulting in an extensive range of diseases.

It should be noted that the term STD should not be confused with STI (sexually transmitted infection). An STI indicates that a person is infected with a certain pathogen, but he is asymptomatic and that infection has not progressed to a disease yet [2]. An STD however, denotes that the infection is not latent anymore but has progressed to the disease. So it should be clear that the term STI has a broader range as it covers everyone with an infection by a known venereal disease causing pathogen and that person, symptomatic or not, has the potential to infect others as well.

Although very diverse on the basis of causative agents and signs, STDs may have a number of things in common. Some of these symptoms include: red, swollen and painful genitals, discharge from penis or vagina, ulcers or warts, burning micturition [8], etc.

Definition

A sexually transmitted disease is a bacterial, viral or fungal infection that infects the genital tract.

Cause

The microbes may enter the body through unprotected vaginal, anal or oral sex, or from contaminated needles and blood [6].

Signs and Symptoms

Common signs and symptoms include red swollen genitals, discharge from the penis or vagina, a feeling of burning pain during urination, warts, ulcers, etc.

Treatment

Treatment is usually of an antibiotics course.

Prevention

STDs can be very easily avoided if proper precautionary measures are taken. These include use of latex condoms during sex, regular testing for STDs if multiple sexual partners, spreading awareness among youngsters, etc.

1. Naidu KM. Epidemiology and Management. Community Health Nursing. Gyan Publishing House 2010. p. 248.
2. Department of Public Health, City & County of San Francisco (2011). STD Risks
3. Pearson R. Pinworm Infection. Merck Manual Home Health Handbook 2007
4. Verdonck K, González E, Van Dooren S, Vandamme AM, Vanham G, Gotuzzo E. Human T-lymphotropic virus 1: Recent knowledge about an ancient infection. The Lancet Infectious Diseases 2007 7 (4): 266. 
5. Villhauer T. Condoms Preventing HPV?. University of Iowa Student Health Service/Health Iowa 2005
6. Quilliam S. The Cringe Report.  J Fam Plann Reprod Health Care 2011. 37(2): 110–112.
7. Shafer MA, Moscicki AB. Sexually Transmitted Infections, 2006. pp. 1–8.
8. Oriel JD. The Scars of Venus: A History of Venereology. London: Springer-Verlag 1994
9. Gilbert MT, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE, Worobey M. The emergence of HIV/AIDS in the Americas and beyond. Proc. Natl. Acad. Sci. U.S.A. 2007 104 (47): 18566–70. 
10. CBC News Staff, Study traces origins of syphilis in Europe to New World. January 2008