Sexually Transmitted Infections-(STIs)

Sexually transmitted infections (STIs) are infections that are spread primarily through person-to-person sexual contact. There are more than 30 different sexually transmissible bacteria, viruses and parasites.The most common conditions they cause are gonorrhoea, chlamydial infection, syphilis, trichomoniasis, chancroid, genital herpes, genital warts, human immunodeficiency virus (HIV) infection and hepatitis B infection. Several, 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 more than 30 different bacteria, viruses and parasites and are spread predominantly by sexual contact, including vaginal, anal and oral sex. Some STIs may be spread via skin-to-skin sexual contact. The organisms causing STIs can also be spread through non-sexual means such as blood products and tissue transfer. Many STIs—including chlamydia, gonorrhoea, hepatitis B, HIV, HPV, HSV2 and syphilis—can also be transmitted from mother to child during pregnancy and childbirth.

A person can have an STI without having obvious symptoms of disease. Therefore, the term “sexually transmitted infection” is a broader term than “sexually transmitted disease”

(STD). Common symptoms of STDs include vaginal discharge, urethral discharge in men, genital ulcers, and abdominal pain.Eight of the more than 30 pathogens known to be transmitted through sexual contact have been linked to the greatest incidence of illness. Of these 8 infections, 4 are currently curable: syphilis, gonorrhoea, chlamydia and trichomoniasis. The other four are viral infections and are incurable, but can be mitigated or modulated through treatment: hepatitis B, herpes, HIV, and HPV.

Prevention of STIs

Counselling and behavioural approaches

Counselling and behavioural interventions offer primary prevention against STIs (including HIV), as well as against unintended pregnancies. These include:

• comprehensive sexuality education, STI and HIV pre- and post-test counselling;
• safer sex/risk-reduction counselling, condom promotion; and 
• interventions targeted at key and vulnerable populations, such as adolescents, sex workers, men who have sex with men and people who inject drugs.

In addition, counselling can improve people’s ability to recognize the symptoms of STIs and increase the likelihood they will seek care or encourage a sexual partner to do so. Unfortunately, lack of public awareness, lack of training of health workers, and long-standing, widespread stigma around STIs remain barriers to greater and more effective use of these interventions.

Barrier methods

When used correctly and consistently, condoms offer one of the most effective methods of protection against STIs, including HIV. Female condoms are effective and safe, but are not used as widely by national programmes as male condoms.

Diagnosis of STIs

Accurate diagnostic tests for STIs are widely used in high-income countries. These are especially useful for the diagnosis of asymptomatic infections. However, in low- and middle-income countries, diagnostic tests are largely unavailable. Where testing is available, it is often expensive and geographically inaccessible; and patients often need to wait a long time (or need to return) to receive results. As a result, follow up can be impeded and care or treatment can be incomplete.

The only inexpensive, rapid blood test currently available for an STI is for syphilis. This test is already in use in some resource-limited settings. The test is accurate, can provide results in 15 to 20 minutes, and is easy to use with minimal training. Rapid syphilis tests have been shown to increase the number of pregnant women tested for syphilis. However, increased efforts are still needed in most low- and middle-income countries to ensure that all pregnant women receive a syphilis test.

Several rapid tests for other STIs are under development and have the potential to improve STI diagnosis and treatment, especially in resource-limited settings.

Treatment of STIs

Effective treatment is currently available for several STIs.

• Three bacterial STIs (chlamydia, gonorrhoea and syphilis) and one parasitic STI (trichomoniasis) are generally curable with existing, effective single-dose regimens of antibiotics.
• For herpes and HIV, the most effective medications available are antivirals that can modulate the course of the disease, though they cannot cure the disease.
• For hepatitis B, immune system modulators (interferon) and antiviral medications can help to fight the virus and slow damage to the liver.

Resistance of STIs—in particular gonorrhoea—to antibiotics has increased rapidly in recent years and has reduced treatment options. The emergence of decreased susceptibility of gonorrhoea to the “last line” treatment option (oral and injectable cephalosporins) together with antimicrobial resistance already shown to penicillins, sulphonamides, tetracyclines, quinolones and macrolides make gonorrhoea a multidrug-resistant organism. Antimicrobial resistance for other STIs, though less common, also exists, making prevention and prompt treatment critical.

STI case management

Low- and middle-income countries rely on syndromic management, which is based on the identification of consistent groups of symptoms and easily recognized signs (syndromes) to guide treatment, without the use of laboratory tests. This approach, which often relies on clinical algorithms, allows health workers to diagnose a specific infection on the basis of observed syndromes.Syndromic management is simple, assures rapid, same-day treatment, and avoids expensive or unavailable diagnostic tests. However, this approach misses infections that do not demonstrate any syndromes - the majority of STIs globally.

10 FACTS ABOUT STIs

1. Sexually transmitted infections (STIs) are mostly spread from one infected person to another through sexual intercourse. Some infections may also be transmitted from mother to child during pregnancy and childbirth. Another way that infections are passed on is through the sharing of blood products or tissue transfers. Some diseases caused by STIs include syphilis, AIDS and cervical cancer.
2. STIs often exist without symptoms, particularly in women. Thus, men and women with sexual partners who have STI symptoms should seek care regardless of a lack of signs. Whenever an infection is diagnosed or suspected, effective treatment should be provided promptly to avoid complications.
3. STIs disproportionately affect women and adolescent girls. Every year, one in 20 adolescent girls gets a bacterial infection through sexual contact, and the age at which infections are acquired is becoming younger and younger. Improving awareness and knowledge of STIs and how to prevent them among adolescents should be part of all sexual health education and services.
4. Sexually transmitted infections are important causes of Fallopian tube damage that lead to infertility in women. Between 10% and 40% of women with untreated chlamydial infections develop symptomatic pelvic inflammatory disease. Post-infection damage of the Fallopian tubes is responsible for 30% to 40% of female infertility cases.
5. In pregnancy, untreated early syphilis is responsible for 1 in 4 stillbirths and 14% of neonatal (newborn) deaths. About 4% to 15% of pregnant women in Africa test positive for syphilis. Interventions to more effectively screen pregnant women for syphilis and prevent mother-to-child transmission of the disease could prevent an estimated 492 000 stillbirths per year in Africa alone.
6. One of the most deadly sexually transmitted infections is the human papilloma virus (HPV). Virtually all cervical cancer cases are linked to genital infection with the virus. Cancer of the cervix is the second most common cancer in women, with about 500 000 new cases and 250 000 deaths each year. The new vaccine that prevents the infection could reduce these cervical cancer-related deaths.
7. When used properly and consistently, condoms are one of the most effective methods of protection against STIs, including HIV infection. Although the female condom is effective and safe, it is not as widely used in national programmes because of its higher cost when compared to male condoms.
8. The partner notification process, which is an integral part of STI care, informs sexual partners of patients about their exposure to infection so that they can seek disease screening and treatment. Partner notification can prevent reinfection and reduce the wider spread of infections.
9. Social or economic conditions, and some sexual behaviours increase a person's vulnerability to STIs. Populations most-at-risk for sexually transmitted infections vary from setting to setting, depending on local culture and practices. Interventions to prevent and care for STIs should be intensified for such populations, while ensuring that services minimize potential stigmatization and discrimination
10. A global strategy to accelerate prevention and control of STIs was developed by WHO through broad consultation among Member States and partners, and then endorsed by the World Health Assembly in May 2006. To build momentum and effectiveness, the 10-year plan includes technical and advocacy components that can be adapted for use around the world.

Source: WHO.int