Sexually Transmitted Diseases

Sexually transmitted diseases (STDs) are a group of communicable diseases that are transferred predominantly by sexual contact and are thus to a large extent "behavioral diseases". Over the past decade, they have continued to be the most commonly notifiable infectious conditions nationally and worldwide. With the escalating epidemic of HIV infection, there has been new attention focused on the spread of STDs in general, raising concerns about both the clinical and social implications of these infections. Recognising a disease as sexually transmitted has several practical consequences for the clinician. In this section we would only discuss about some of the most prevalent STDs worldwide.

Gonorrhea Epidemiology

In 1990, WHO estimated 35 million cases of gonorrhea worldwide, second to Chlamydia trachomatis amongst STDs. In developed countries the trends show a clear increase from 1957 onwards. reaching a peak in the early Seventies and decreasing since but in Asia and Africa it still remains high. A significant peak of gonorrhea is seen in late summer and a trough in winter.

Clinical Features

In Males :

Gonococcal urethritis in males is characterised by a yellowish, purulent urethral discharge and dysuria. The usual incubation period is 2 to 6 days. The discharge of gonorrhea is slightly more copious and purulent than in nongonococcal urethritis. Symptoms are probably produced by 90 per cent of infections, although asymptomatic infections do occur and may persist for many months.

Asymptomatic men are increasingly understood to be major facilitators of gonococcal transmission. Recognition of a male reservoir for transmission, in addition to the substantial burden of asymptomatic disease in women, is necessary in order for adequate measures to be taken. About a quarter of homosexual men attending screening clinics have evidence of anorectal gonorrhea.

Gonococcal infection of the rectum causes a wide spectrum of symptoms, ranging from asymptomatic carriers to severe proctitis with tenesmus and bloody, mucopurulent discharge.

In Females :

In prevalence studies, approximately half of the women infected with the gonococcus are asymptomatic or have so few symptoms that they do not seek medical care. The most commonly involved site is the endocervix (80-90 per cent), followed by the urethra (80 per cent), rectum(40 per cent) and pharynx (10-20 per cent). Most pharyngeal, urethral, and rectal infections cause few or no symptoms. Cervical infection may result in vaginal discharge or abnormal menstrual bleeding'. Although approximately 40 per cent of females with cervical gonorrhea also have positive rectal cultures, symptoms of proctitis in females are unusual.

In Children :

Infants born to a mother with cervicovaginal gonorrhea may develop a gonococcal conjunctivitis, although routine use of prophylactic 1 per cent silver nitrate eye drops has markedly reduced the incidence of this problem. Neonates may also acquire pharyngeal, respiratory or rectal infection and may develop gonococcal sepsis. Older children up to 1 year of age usually acquire conjunctival or vaginal infection by accidental contamination from an adult, whereas from 1 year to puberty most childhood gonorrhea is the result of purposeful sexual abuse by an adult.

Differential Diagnosis

Uncomplicated gonorrhea

Males : Nongonococcal urethritis

Females :
Urinary infection, Trichomoniasis, Candidosis, Bacterial vaginosis

Both Sexes : Proctitis, Pharyngitis.


Neisseria gonorrhoeae (gonococcus) can be identified from infected areas by Gram stain and culture on special media (i.e. antibiotic-containing media). Blood culture and synovial fluid investigations should be performed in cases of disseminated infection. Coexisting pathogens such as chlamydia, trichomonas and treponema must be sought. New non-culture methods such as genetic probe techniques have become available. These techniques are especially useful in areas where specimen transport is an issue.


Syphilis Epidemiology

Syphilis has been recognised for centuries in the developed countries. The number of cases of primary and secondary syphilis were at the peak during the Second World War and dropped to a low level in the late 1950s with a slow but steady increase since that time. However, from 1986 there has been an epidemic of primary and secondary syphilis in the USA with increases ranging from 10-200 per cent in 25 cities. In developing countries sero-prevalence rates are high varying from 5-20 per cent in women attending antenatal clinics to 70 per cent in certain groups, e.g., prostitutes.

As syphilis is acquired almost exclusively by intimate contact with the infectious lesions (chancre, mucus patches, condylomata lata), the disease is most common in young, sexually active individuals. The highest rate in both men and women occurs at ages 20-24 followed by ages 25-29 and 15-19 years.

It is more prevalent among the poorly educated and economically deprived groups. The ratio for male : female was about 3:1 in the mid 1980's. The occurrence is more in male homosexual than in female homosexual. Infant deaths from syphilis fell by 98 to 99 per cent by 1980 but rose sharply in 1988-90.

Clinical Features

Primary Syphilis :

The first clinical sign of primary stage of syphilis is the development of a chancre at the site of treponemal inoculation approximately three weeks after initial exposure. Chancres are usually located on external genitalia, where they are painless unless secondarily infected. Lesions in the anal canal and perianal area have been noted more frequently in homosexual males. Genital chancres in women can be missed because of their location in the vagina or on the cervix, where they may resemble a cervical erosion or even an ulcerating carcinoma. Chancres, usually heal spontaneously within 2 to 6 weeks.

Secondary Syphilis :

Approximately 4 to 8 weeks following the appearance of the primary chancre, patients typically develop lesions of secondary syphilis. They may complain of malaise, fever, headache, sore throat, and other systemic symptoms. Most patients have generalised lymphadenopathy including the epittrochlear nodes. Approximately 30 per cent of patients have evidence of the healing chancre, although many patients including male homosexuals and women have no history of a primary lesion. At least 80 per cent of patients with secondary syphilis have cutaneous lesions or lesions of the mucocutaneous junctions at some point in their illness. The rashes often are pink, coppery, or dusky red, particularly the earliest macular lesions. The earliest pink macular lesions are frequently seen on the margins of the ribs or the sides of the trunk with later spread to the rest of the body. The face is often spared except around the mouth. Ringed or annular lesions may occur, especially around the face, particularly on black individuals. Lesions at the angle of the mouth or the corner of the nose may have a central linear erosion (the so called "split papule"). The rash is often minimally symptomatic. However, many patients with late syphilis do not recall either primary or secondary lesions.

In warm moist areas such as in the perineum, large, pale, flat-topped papules may coalesce to form condylomata lata. These may also be seen in the axilla and rarely in a generalized form. They are extremely infectious.

Other manifestations of secondary syphilis include hepatitis, which has been reported in upto 10 per cent of patients in some series. Jaundice is rare, but an elevated alkaline phosphatase is common.

Late Syphilis (tertiary syphilis) :

This includes late latent syphilis also referred to as benign tertiary syphilis, involvement of viscera, the CNS, and the aorta.

Neurosyphilis :

The clinical manifestations of symptomatic neurosyphilis can take a variety of forms. Meningovascular syphilis is an inflammatory process that becomes clinically evident 10 years after the initial infection. It may present as a stroke in younger individuals, producing hemiparesis, aphasia, and visual disturbances. Patenchymatous neurosyphilis is a desenerative disorder that includes general paresis and tabes dorsalis. Both generally occur 15 to 20 years after priman infection. General paresis, now uncommon, presents clinically as dementia, speaking defects, impaired judgement and rarely, delusions. If untreated, paresis progresses to paralysis and further mental and physical deterioration.

Cardiovasular Syphilis :

The primary cardiovascular complications of syphilis are aortic insufficiency and aortic aneurysm, usually of the ascending aorta. Less commonly other large arteries may be involved, and rarely involvement of the coronary ostia results in coronary insufficiency.

Anal Syphilis :

An anal chancre is a common manifestation of primary syphilis. Three quarters of those infected are homosexual men. The chancre appears two to six weeks after exposure during anal intercourse. It may be confused with an anal fissure and when secondary bacterial infection supervenes can cause considerable pain at the anus.

Relapsing Syphilis :

Condylomata lata are likely to recur. The skin manifestations tend to be unilateral; the eruptions more dense, marked with fewer lesions, and sometimes solitary. They are also more infiltrated and of somewhat longer standing and have some characteristics that resemble the skin lesions in late syphilis. This reflects the increasing immunity with the duration of the early disease. Neurorecurrences, as well as ophthalmic and other relapsing manifestations may occur.

Latent Syphilis :

By definition the patient is asymptomatic with normal CSF findings but positive serology. It is arbitrarily divided into early (<2 years) and late latent (>2 years) syphilis. Infectiousness does not stop with the advent of latency as women may continue to give birth to congenitally infected infants during the early latent stage or for at least two years into the latent stage. Approximately 60 per cent of patients remain latent for the rest of their lives, the only evidence of syphilis being positive serology with usually a low titer. The rest develop clinical late syphilis but autopsy studies indicate that a higher proportion has subclinical infection especially of the cardiovascular system.

Congenital Syphilis :

Infection of the fetus in utero can occur in any untreated pregnant woman but is most likely to occur in the early stages of infection. Early congenital syphilis is often manifested by a rhinitis, which is followed by a diffuse maculopapular rash with widespread sloughing of the epithelium. There may be a generalised osteochondritis and perichondritis that could lead to areas of bone destruction. The liver is often involved. Neonatal death is usually secondary to liver failure, pneumonia, or pulmonary haemorrhage. Congenital syphilis may progress to a latent phase if the untreated child survives.

It can occur as late as 30 years after birth, with optic atrophy and eighth nerve deafness. Other late characteristics of latent congenital syphilis include arthropathy and bilateral knee effusions, and widely spread peg-shaped upper central incisors (Hutchinson's teeth). Neurosyphilis may also develop.

Differential Diagnosis

Secondary Syphilis :

Congenital Syphilis :


Treponema pallidum is not amenable to in vitro culture - the most sensitive and specific method. It is usually identified by dark ground microscopy.

The following serological tests are used which are either treponemal specific or non specific. All serological investigations may be negative in early primary syphilis.

The VDRL (Venereal Disease Research Laboratory) test is non-specific but is a useful screening test, becoming positive within 3-4 weeks of the primary infection. As it generally becomes negative by six months after treatment, this can be used to monitor treatment efficacy and is helpful in assessing disease activity. The VDRL may also become negative in untreated patients (50 per cent of patients with late stage syphilis). False-positive results may occur in other conditions particularly infectious mononucleosis, hepatitis, mycoplasma infections, some protozoal infections, Cirrhosis. malignancy, autoimmune disease and chronic infection.

T. pallidum hemagglutination assay (TPHA) is highly specific for treponemal disease but will not differentiate between syphilis and other conditions such as yaws.

The fluorescent treponema antibodies absorbed test (FTA-ABS) is positive in more than 90 per cent of patients with primary infection and in all patients with latent and late syphilis. It remains positive for life even after treatment. It is also highly specific for treponemal disease but cannot differentiate between syphilis and some other conditions (e.g., yaws).

In certain cases examination of the CSF for evidence of neurosyphilis and a chest X-ray to determine the extent of cardiovascular disease will be indicated.


The most common complication of late syphilis was late benign syphilis or gumma but in the era of penicillin gummas are rare. They typically develop from one to 10 years after the initial infection and may involve any part of the body.

The primary cardiovascular complications of syhilis are aortic insufficiency and aortic aneurysm, usually of the ascending aorta. Less commonly other large arteries may be involved. Rarely involvement of the coronary ostia results in coronary insufficiency. Death may eventually result from congestive heart failure.

Chlamydial Infections Epidemiology

Genital infections caused by C. trachomatis are the most common bacterial sexually transmitted syndromes in the United States. In men 30-40 per cent of non-gonococcal and postgonococcal urethritis is due to chlamydia. It is frequently found in association with other pathogens : 20 per cent of men and 40 per cent of women with gonorrhea have been found to have co-existing chlamydial infections. Although chlamydial urethral infection is less frequent in homosexual men, it is a major cause of proctitis. Prevalence of chlamydial infection also tends to be higher in non-whites than in whites.

Clinical Features

Chlamydial infections are associated with a wide range of clinical states ranging from asymptomatic infection to urethritis, epididymitis, and proctitis in the male; cervicitis, salphingitis, and acute urethral syndrome in the female; and conjunctivitis and pneumonia-in-the newborn.

Majority of women are asymptomatic. Findings suggestive of chlamydial cervicitis include easily induced endocervical bleeding, mucopurulent endocervical discharge, and hypeterophic ectopy. The presence of endometritis correlates with a history of intermenstmal bleeding. The proportion of women with cervical chlamydial infection who develop upper genital tract infection (endometritis, salpingitis, pelvic peritonitis) is thought to be significant. Infertility due to obstructed fallopian tubes and ectopic pregnancy have been correlated.

Majority of women with urethral infection do not have dysuria or frequent urination. However, chlamydial urethritis should be suspected in young women with dysuria lasting for more than seven to 10 days, lack of hematuria and suprapubic tenderness, use of birth control pills, and sterile pyuria.

Recent studies have suggested that chlamydia is sometimes associated with perihepatitis with right upper quadrant pain, fever, nausea and vomiting, and salphingitis.

Dark ground microscopy showing tightly coiled Treponema palliadum

Chlamydia trachomatis infection is an important cause of proctitis among those who practise anoreceptive intercourse. Many such people harbour sub-clinical infections. Symptoms include a mucoid or blood stained discharge, pain, tenesmus, and fever. Sigmoidoscopy shows a non-specific proctitis and many have inguinal lymphadenopathys.


Cell culture systems are still considered the definitive method of diagnosis but are costly and not suitable for routine use. Antigen detection systems depending on either direct fluorescent antibody or enzyme-immunoassay are increasingly available. Wooden swabs may interfere with assay techniques. Special transport media are required.


Men suffer fewer complications than women, because the urethra is usually the only site affected producing scanty, mucopurulent discharge and dysuria. Occasionally in men it causes epididymitis and orchitis which may result in infertility. Rectal infection leading to proctitis may occur in men practising anoreceptive intercourse. In women it can cause salphingitis and healing may result in tubal scarring with occlusion and infertilirys.

Nongonococcal Urethritis


Nongonococcal Urethritis (NGU), formerly called non-specific urethritis occurs worldwide. According to the data given by STD clinics in England in 1982 it has shown that the occurrence is about three times more in men than in women. Male patients with NGU are more often married and older patients with NG genital infections belong to a higher socio-economic class. No race is exempt though it appears that NGU and its complications are more frequent in Caucasians than in Blacks. In case of seasonal variations a significant peak of NGU is observed in late summer and a trough in winter.

Clinical Features

In Men: The incubation period of NGU varies from a few days to six weeks. The onset is less acute than in gonorrhea and the patient presents with mucopurulent discharge and dysuria. There may be discomfort in the shaft of the penis or meatus. At times the discharge is seen only first thing in the morning after accumulation overnight and before being washed away by the first urination and may be ignored by the patient and not seen by the doctor. Cystitis is not a feature except for the very rare 'abacterial hemorrhagic cystitis' which has a hyperacute onset with the patient complaining of frequency of urination even 15 minutes or so, dysurea, and malaise. The urine contains a great deal of pus and macroscopically visible blood. The condition is sometimes followed by Reiter's disease. If untreated, the discharge will eventually cease but this may take weeks, rarely even months. if treated with Tetracycline, there is a rapid response within a week in 80-90 per cent of cases; if given a placebo, there is a similar response in about 20 per cent. However, this difference becomes less as time goes on and at three months may be only 10 per cent in favor of Tetracycline because of recurrences during this period. NGU has a marked tendency to recur and it is often impossible to decide whether one is dealing with a new infection or a recurrence of the old one. Even when the regular sexual partner has been treated with the same drug, at the same time as the patient, recurrences do occur. However, some claim that if such treatment is given to couples carrying C. trachomatis, the recurrence rate is greatly reduced.


Smears should be taken from the urethra when the patient has not voided urine for at least four hours and should be Gram stained and examined under a high power (x 1000) oil immersion lens. The presence of five or more polymorphonucleocytes per high power field is diagnostic. Men who are symptomatic but have no objective evidence of urethritis should be re-examined and tested after holding urine over night. Cultures for gonorrhea must be taken together with swabs for chlamydia testing.


Patients with NGU tend to complain of discharge or dysuria rather than both. NGU can accompany Stevens-Johnson syndrome. It can also be a part of Reiter's syndrome and seems to follow urethral infections with C. trachomatis.

Chancroid Epidemiology

Chancroid occurs sporadically throughout the Western Hemisphere, Europe and Australia, but it is highly prevalent and endemic throughout most of Sub-Saharan Africa and South East Asia. Before sulfonamide, chancroid was the most common cause of genital ulceration in the world, and it remains so in endemic areas. The majority of reported cases occur in males. An outbreak in Greenland was exceptional in that about 40 per cent of cases were noted in women. It is quite likely that there has been significant underdiagnosis in women in the past.

Clinical Features

Clinical features include painful, friable suppurative ulceration, with common adjacent discrete lesions. In the female, genital lesions are often introital, especially of the fourchette. In the male, they are often subpreputial and have a predilection for the coronal sulcus and the frenulum. The ulcers are distinctive, painful lesion with undermining of the cutaneous border. Suppuration and friability are also characteristic. In 50-70 per cent of chaneroids, the regional lymph nodes enlarge unilaterally and become tender shortly after the lesion appears. In 30-50 per cent of cases, the lymph nodes fuse together and form a painful bubo. Other uncommon clinical variants include the phagedenic type of ulcer with secondary suprainfection and rapid tissue destruction, giant chancroid, serpiginous ulcer and multiple small follicular type of ulcer in a perifollicular distribution.

Differential Diagnosis



Three diagnostic methods are used to diagnose chancroid-Gram stain, auto-inoculation and culture. Culture of H. ducreyi is specific and preferred method of diagnosis. Best culture results seem to be obtained with a chocolate agar medium containing 3mg/ml of Vancomycin. The organisms can be identified in smears of ulcer, buboaspirate and aspiration of inguinal nodes.


Cervical cancer is estimated to cause 500,000 death each year worldwide. The public health impact of controlling precursor cervical lesions and cancer is potentially huge, especially in developing countries where the incidence rate of cervical cancer is 40 per 100,000 women. Recent investigations indicate that Human Papillomavirus, (HPV) play an important role in premalignant and malignant lesions of the cervix and have important ramification for the diagnosis, screening and treating the associated disease.

Papillomaviruses are a genera of viruses grouped together by their tumorigeniciry and homogeneity of DNA. They infect a wide variety of vertebrates, including man. To date, more than 70 types of HPV have been described. Each type shows a particular tropism to specific anatomic sites. Cutaneous infections and mucosal infection of anogenital, oral and respiratory epithelial are common.

Attention has focused on the association between anogenital infection with HPV and the development of cervical dysplasia and invasive cervical cancer. In a study of 2600 cervical smears, highly oncogenic DNA from HPV type 16 was found in 47 per cent of high grade squamous intraepithelial lesions and 47 per cent of invasive cancers by Southern blotting. Genomic HPV DNA is functionally divided into early and late genes. The early genes are responsible for DNA replication. transcriptional regulation, and transformation. The late genes encode the major and minor capsid proteins. Early genes products act as oncogenic proteins. A recent report indicates that injection of peptide fragments of early genes into mice induced protective cell mediated immune responses against formation of tumors.

As we continue to unravel the cellular and molecular mechanism responsible for carcinogenesis and its relation to infection with HPV, targeted strategies for prevention and treatment of the disease will become a reality. These strategies may affect gene regulation or protein expression or they may exploit Immoral and cell mediated immunity to affect prevention and rejection of tumorsis.

Herpes Genitalis

In the United Kingdom the incidence of genital herpes is increasing. An increase of over 21 per cent was observed from the year 1982 -1983.

Genital herpes is usually caused by Herpes simplex virus type 2(HSV-2) and for less frequently by Herpes simplex virus type 1(HSV-1). Following the primary episode, the virus persists in the presacral-ganglia in a latent form and may be reactivated to cause recurrent infections. Genital herpes is potentially a far more serious condition in women than men because of the risk of their transmitting the infections to their infants, the suggestion that the virus is directly or indirectly a cause of cervical carcinoma and, least important, the greater severity of the primary attack.

Genital herpes is transmitted by sexual intercourse. The danger period for infection is still considerable after the painful lesions become painless and the patient is assumed to be non-infectious, yet virus shedding may continue for up to two weeks. Asymptomatic shedding of virus from the cervix has been found especially in prostitutes who may form an infectious reservoir of HSV-2 infection. An infected mother can transmit herpes to the neonate during delivery.

The lesion starts as a patch of erythema followed rapidly by one or several groups of papules or vesicles which break down to form shallow ulcers.

These crust over and after separation of the crust usually heal without recurring. The lesions are painful and irritating - an important diagnostic feature. Regional tender inguinal lymphadenopathy is associated with the primary attack but rare in recurrences. Symptoms include urethral or vaginal discharge, perianal pain, dysuria, rectal pain, tenesmus, itching, constipation and rectal discharge. One of the most frustrating aspect of genital HSV infections is the tendency for recurrence in nearly all patients. Isolation of HSV by tissue culture of vesicles (ideally 24-48 hr old) remains the most definitive form of diagnosis.

Microscopic examination of scrapings, from lesions using Giemsa or Wright's stain (RXZNCK test) may be used to show the characteristic cellular morphology of HSV infection. Serologic tests are helpful only in primary infections, since antibody titer remain relatively unchanged during recurrent disease.

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