Sexually Transmissible Diseases

What is Sexually transmissible diseases?

Sexually transmissible diseases are infections that can be passed from one person to another through sexual activity. Since the human body cannot become immune to sexually transmissible diseases, people with multiple sexual partners may acquire the same infection repeatedly or more than one infection at the same time. However, ordinary social contacts such as shaking hands, sharing meals, swimming in public pools and travelling on public transport will not spread these infections.

The common sexually transmissible diseases include trichomoniasis, genital warts, genital herpes, gonorrhoea, syphilis and chlamydia, etc. Acquired lmmune Deficiency Syndrome (AIDS) is also a sexually transmissible disease.


Trichomoniasis is caused by a single-cell parasite. Incubation takes from 4 to 20 days.

Trichomonas infection in men is usually asymptomatic. Some men may experience pain on urination and discharge thick greyish yellow pus from the urethra. About half of the infected women also have no symptoms. Some have vagnitis with symptoms such as vaginal itching, increased vaginal discharge which is yellow and greenish with an unpleasant smell, and a burning sensation during urination and sexual intercourse.

Genital Warts

Genital warts, unlike ordinary skin warts, are transmissible through sexual intercourse. The incubation period generally ranges from 1 to 8 months, with an average of about 3 months.

The person infected with genital wart virus develops small, fleshy and pinpointed, or flat growths on the skin or mucous membrane of the genital areas. The warts will grow in size and form clusters. These clusters tend to ulcerate, bleed and become inflamed. In men, warts often appear around the prepuce, glans of the penis or the urethral opening. In women, warts are most frequently found on the vulva, labia, vagina and cervix. For those who engage in anal intercourse, warts may also be found around the anus or the perineum.

Genital Herpes

Genital herpes, caused by Herpes Simplex Type ll virus, is transmitted when herpes lesions come into contact with mucous membrane or broken skin, most commonly through sexual intercourse. Incubation averages 2 to 5 days.

After the incubation period, the infected person develops symptoms such as fever, muscle pain, frequent urination with a burning sensation and swelling of lymph nodes, etc. There will be an itching sensation in the penis, urethra, labia or cervix, followed by the appearance of small vesicles in these areas. For those who engage in anal intercourse, vesicles may appear in and around the anus. These vesicles will soon fester and rupture to become very painful ulcers leaking clear fluid.

The above symptoms automatically disappear in about 3 weeks. However, the virus remains dormant in the nervous system of most of the infected people, giving rise to recurrent but milder attacks of genital herpes.

Pregant women infected with genital herpes may transmit the virus to their babies through the birth canal. Over 60% of the infected infants are expected to die , while the rest may have widespread infection with serious complications of brain infection and mental retardation. Pregnant women who have a history of genital herpes should therefore inform their health care providers during antenatal check-ups. If a recurrent attack occurs near the time of delivery, a caesarean section may help reduce the risk of infecting the newborn.

Anyone suspected of suffering from genital herpes infection should seek early advice and treatment. There is as yet no complete cure for herpes, but drugs are available to reduce the discomfort and incidence of recurrence.


Gonorrhoea is caused by a bacterium and mainly transmitted through sexual intercourse with an infected person. Symptoms usually appear 1 to 14 days after infection.

Symptoms are usually more conspicuous in men, and include a yellowish, purulent discharge from the urethra, and frequent urination with a burning sensation. However, about 10% of the men experience no symptoms at all. If not treated promptly, gonorrhoea can infect the other genital areas such as the epididymis, prostate and urethral glands, leading to narrowing of the urethra, difficulty in urination and even kidney failure. Those who engage in oral or anal intercourse may suffer from gonorrhoea infection of the throat or the rectum.

Gonorrhoea frequently goes undetected in women because about 50-80% of the infected women have no symptoms. Some have purulent vaginal discharge, and some experience frequent and painful urination. Gonorrhoea can cause infection of the Bartholin glands, pelvic cavity as well as fallopian tubes, resulting in infertility. Women who engage in oral or anal intercourse may also suffer from gonorrhoea infection of the throat or the rectum.

An infant may suffer from infection of the eyes through exposure to the mother's infected birth canal. Blindness may result if the infection is not treated properly.

It is essential for a person suffering from gonorrhoea to seek early diagnosis and treatment in order to prevent serious complications and permanent damage to the infected organs.


Syphilis is mainly transmitted through vaginal, oral and anal sex with an infected person. The corkscrew-shaped syphilis organism can also be transmitted through the placenta from the blood of an infected mother to her baby. Transfusion of infected blood can also transmit the disease.

Syphilis is a serious disease. If left untreated, it may lead to various complications and can even result in death. An infected person presents varying symptoms at different stage of the disease:

Primary Stage

Incubation takes from 9 to 90 days, although most people develop symptoms in 3 to 4 weeks after infection. In the initial stage, painless sores appear on the genital areas. These are more easily noticed in men but may be missed in women whose lesions develop inside the vagina.

These lesions will disappear with or without treatment. But if untreated, the organism will spread to the rest of the boby and the disease will progress to the secondary stage.

Secondary Stage

About 6 to 8 weeks after the sores have healed, the person may develop non-itchy and painless skin rash, mouth ulcers, fever, enlarged lymph nodes or flu-like symptoms. These symptoms will eventually subside and the disease then enters the latent stage.

Latent Stage

An infected person at this stage has no signs and symptoms. Only a blood test can detect the presence of syphilis.

Late Syphilis

Signs of late syphilis may appear several to many years after the initial infection. The organism will affect the heart, major biood vessels and central nervous system, causing blindness, mental illness, handicap and even death.

Syphilis is treatable. Once cured, a person can resume normal sexual activity but should still visit the doctor regularly for physical check-up and blood test. Prompt treatment can also prevent the disease from being transmitted from an infected pregnant women to her baby.


Chlamydia is a less commonly known sexually transmissible disease. Incubation ranges from 7 to 21 days.

Symptoms in men include difficulty in urination and a white or clear discharge from the penis. Women may experience vaginal itching, increased vaginal discharge, pelvic or abdominal pain, difficulty in urination and abnormal vaginal bleeding. Since about 70% of women and 25% of men have no symptoms at all, it is common for infected persons to spread the disease unknowingly.

Chlamydia infection can have serious consequences for both men and women. In men, it may cause inflammation of the testes, seminal vesicle and vas deferens. In women, infection usually spreads from the uterus to the fallopian tubes, causing inflammation and adhesion of the tubes which may lead to future ectopic pregnancy or infertility. Apart from sexual contact, the disease has a high chance of transmission during childbirth. The baby of an infected mother is likely to contact the disease when it passes through the birth canal, and suffer from chlamydial conjunctivits or pneumonia.

Chlamydia infection can be treated with antibiotics and treatment is usually simple. But if the infection leads to pelvic inflammation or infertility, then treatment will be much more complicated. It is therefore very important for an infected person to seek early and proper diagnosis and treatment.


AIDS is caused by the human immunodeficiency virus (HIV). The virus progressively destroys the immune system so that the body is unable to defend itself against illness. A person with HIV may remain well for several years after infection.But over a longer period of time, as the immune system weakens, the infected person may develop particular illnesses such as opportunistic infections and tumours, etc. When this happens, the person is said to have AIDS (Acquired Immune Deficiency Syndrome.)

HIV is mainly present in blood, semen and vaginal secretions. Only a very small quantity of the virus is present in saliva. The virus does not easily pass through the intact skin but may penetrate the much thinner mucous membrance of the mouth and rectum. HIV is mainly transmitted in three ways:

Unprotected penetrative sex where semen, vaginal secretion or blood of an infected person is contacted;

Infection of a baby by its HIV infected mother during pregnancy, childbirth or breast-feeding;

Exposure to the virus through open wounds or mucous membrane of the eyes, nasal and oral cavity, or by sharing contaminated needles, or transfusing infected blood or blood produsts.

HIV can be detected through blood tests, except within the first three months after an intital infection which is known as the window period in HIV testing. Hence to ensure an accurate test result, a person undergoing blood test for HIV must be tested again six months later. There is as yet no cure for HIV infection. However, effective treatment is now available to help slow down the progression to AIDS, prevent opportunistic infections and alleviate symptoms. Affected persons should therefore maintain a positive attitude.

To minimize the risk of infections, one should avoid unsafe sexual contact, promiscuity and sharing of needles and syringes.

Prevention and Treatments of STDs

Because sexually transmissible diseases (STD) do not always present with obvious symptoms, many infected people fail to obtain prompt treatment and hence spread the virus to others. Most STD can be diagnosed by simple testing of secretion, blood or cell samples. Anyone who suspects STD infection should seek prompt diagnosis irrespective of whether there are symptoms. The sexual partner should also be tested and treated to avoid repeated infection.

Safer sex is the most effective way to prevent STD. This means to have sex only with a single non-infected partner. If this is not possible, condom should be properly used during each sexual intercourse. Sexually active people should receive regular check up in order to safeguard their health.

The FPA clinics provide preliminary screening for a range of STD for women. Appropriate referral for follow-up or treatment can be arranged as necessary. For details, please consult our clinic staff.

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