- Last Updated on 04 December 2012
Sexual Transmitted Infections (STIs)
Sexually transmitted infections (STIs) are infections that are spread primarily through person-to-person sexual contact. Several types, in particular HIV and syphilis, can also be transmitted from mother to child during pregnancy and childbirth, and through blood products and tissue transfer. STIs are caused by bacteria, viruses, and parasites.
The most common conditions they cause are gonorrhoea, chlamydial infections, syphilis, trichomoniasis, chancroid, genital herpes, genital warts, human immunodeficiency virus (HIV) infections, and hepatitis B infections.
There are more than 30 different sexually transmissible bacteria, viruses and parasites. STIs can also cause serious health problems such as infertility, stillbirth, and blindness in newborns.
According to the WHO (Fact sheet N 110, August 2011), there are 448 million new infections of curable sexually transmitted (syphilis, gonorrhoea, Chlamydia and trichomoniasis) infections that occur yearly throughout the world. This does not include HIV and other STIs which continue to adversely affect the lives of individuals and communities worldwide. In developing countries, STIs and their complications rank in the top five disease categories for which adults seek healthcare.
In pregnant women with untreated early syphilis, 25% of pregnancies result in stillbirth and 14% in neonatal death. Sexually transmitted infections are the main preventable cause of infertility, particularly in women. WHO recommends a syndromic approach to diagnosis and management of sexually transmitted infections.
Some STIs exist without symptoms. Both symptomatic and asymptomatic infections can lead to the development of serious complications.
Untreated STIs can have critical implications for reproductive, maternal, and newborn health. STIs are the main preventable cause of infertility, particularly in women.
Untreated STIs are associated with congenital and peri-natal infections in neonates, particularly in regions where rates of infection remain high.
STIs and HIV
The presence of untreated STIs (both those that cause ulcers and those that do not) increases the risk of both acquisition and transmission of HIV by a factor of up to 10. Prompt treatment of STIs is thus important to reduce the risk of HIV infection. Controlling STIs is important for preventing HIV infections, particularly in people with high-risk sexual behaviours.
The most effective means to avoid becoming infected with or transmitting a sexually transmitted infections is to abstain from sexual intercourse (i.e., oral, vaginal, or anal sex) or to have sexual intercourse only within a long-term, mutually monogamous relationship with an uninfected partner. Male latex condoms, when used consistently and correctly, are highly effective in reducing the transmission of HIV and other sexually transmitted infections, including gonorrhoea, chlamydia, and trichomoniasis.
Common bacterial infections
- Neisseria gonorrhoeae (causes gonorrhoea or gonococcal infection)
- Chlamydia trachomatis (causes chlamydia)
- Treponema pallidum (causes syphilis)
- Haemophilus ducreyi (causes chancroid)
- Klebsiella granulomatis (previously known as Calymmatobacterium granulomatis causes granuloma inguinale or donovanosis).
Common viral infections
- Human immunodeficiency virus (causes AIDS)
- Herpes simplex virus type 2 (causes genital herpes)
- Human papillomavirus (causes genital warts and certain subtypes lead to cervical cancer in women)
- Hepatitis B virus (causes hepatitis; chronic cases may lead to liver cancer)
- Cytomegalovirus (causes inflammation in a number of organs including the brain, the eye, and the bowel).
- Trichomonas vaginalis (causes vaginal trichomoniasis)
- Candida albicans (causes vulvovaginitis in women; inflammation of the glans penis and foreskin balanoposthitis in men).
Sources: The WHO