STI is a group of infections caused by microorganism that spread primarily through sexual intercourse. The commonest ones are the curable bacterial infections: syphilis, chlamydia and gonorrhoea. Regular screening for these 3 infections, followed by appropriate treatment, is advisable for sexually active persons, especially if there are sexual activities outside stable monogamous relationship. Viral hepatitis can be transmitted through sex, but these are generally not considered STI. Currently no vaccine is available for STI. Prompt treatment is needed following diagnosis, which contribute to preventing further transmission. The best prevention is avoiding unprotected sex.
Syphilis
What is it? Syphilis is caused by the bacteria called Treponema pallidum. Syphilis can present with wide range of symptoms from an ulcer on the genitalia, rash and other organ manifestations which, if untreated, could lead to long term complications. Diagnosis is by a blood test.
Treatment: Antibiotic treatment.
Prophylaxis: No vaccine available
Gonorrhoea
What is it? Gonorrhoea is caused by the bacteria Neisseria gonorrhoeae which may involve genitals, mouth and/or rectum, resulting in pain and discharge. Complications may include inflammation of reproductive organs, spread to joints and heart. Some may be asymptomatic. Diagnosis depends on urethra swab culture or nucleic acid tests on urine, throat and rectum specimens.
Treatment: Antibiotic treatment; resistance is a concern.
Prophylaxis: No vaccine available
Chlamydia
What is it? Chlamydia is one of the commonest sexually transmitted infection. It may cause pain and give rise to discharge to the genital. Complications may include inflammation of reproductive organs. Nucleic acid tests on urine, throat and rectum specimens are commonly used for diagnosis.
Treatment: Antibiotic treatment.
Prophylaxis: No vaccine available
Hepatitis C
What is it? Infection caused by hepatitis C virus the transmission pattern of which is similar to that for hepatitis B. Hepatitis C is transmitted through contaminated injection and transfusion. It may be sexually transmitted as reported in outbreaks in the MSM community. Chronic infection may lead to cirrhosis and liver cancer.
Treatment: Direct acting antiviral (DAA) for chronic infection.
Prophylaxis: No vaccine available.
Others
What is it? Herpes genitalis, HPV, trichomonas (more common in women) and mycoplasma are other STI which may need medical attention, but no specific recommendations are available. HPV is the cause of wart and could also cause cancer of cervix in female, penis in male, and anus and throat in both sexes.
Treatment: Should seek medical advice.
Prophylaxis: HPV vaccine can protect from HPV infection.