Sexually transmitted infections

Sexually transmitted Infections (STI) are common infections worldwide but the majority of these infections and complications occur in tropical regions of the world. There are various reasons for this such as a fragile health care infrastructure to diagnose and treat these infections; the presence of marginalized populations such as commercial sex workers, illicit drug and alcohol users, core-group transmitters such as military personnel, police workers or truck drivers, and the weak position of women in society.

Human Immunodeficiency Virus (HIV) infection is mainly transmitted through sexual contact and in the presence of traditional STI, such as gonorrhea and syphilis, the risk of HIV transmission is increased approximately threefold [1]. The improvement of STI control not only reduces the morbidity and mortality caused by these traditional STI but also reduces the incidence of HIV infections [2].

Prevention

The transmission of STI may be prevented by abstaining from sexual activity or being faithful to an uninfected sexual partner. The male condom is also highly effective against transmission of STI when used consistently and correctly. They are cheap, often provided for free, and readily available but unfortunately only used in very limited numbers by the general population and high-risk groups, e.g. commercial sex workers frequently fail to negotiate these safe sex measures in male-dominated sexual relations.

We are in dire need of preventive measures that are controlled by women and in this regard new developments are taking place. Tenofovir vaginal gel applied by women, before and after the heterosexual contact, has shown a 40% reduction in newly acquired HIV infection between users and controls but unfortunately this result has not yet been repeated in other studies [3]. Furthermore, there is a United Nations programme underway reintroducing the female condom with two brands already on the market and two different models getting approval in the year 2013. This variety of choice hopefully will make the price go down and make them affordable to the public at large [4].

Diagnosis and treatment

STI are managed using syndromic case management in which, after history taking and physical examination, various clinical syndromes are discerned that may be caused by a restricted number of STI and that are managed according to locally adapted treatment guidelines, partner notification and follow-up [5].

The syndrome of genital ulcer is usually caused by syphilis or chancroid but during the last decades most cases in developing countries are now due to genital herpes. A syphilis ulcer may be painless but is often quite painful especially when secondary bacterial infection has occurred. The border and bottom of the ulcer are indurated and it is often accompanied by bilateral inguinal lymphadenopathy. The ulcer is self-limiting and signs and symptoms of secondary syphilis with various types of skin rashes and condylomata lata may follow. Chancroid ulcers can be multiple with irregular borders and are often quite painful. When inguinal adenopathy is present this may progress towards abscess formation i.e. a bubo. The latter is managed with incision and drainage. The history of the presence of small blisters preceding the grouped shallow ulcers is highly suggestive of genital herpes. Recent studies of genital herpes in young adults in the United States have shown that the majority is now caused by Herpes Simplex Virus type 1 and this is due to an increase of oro-genital sexual practices [6]. In the presence of HIV co-infection the clinical characteristics of these STI may change, often leading to an increase in ulcer size and a more protracted course.

Congenital syphilis

Recent studies estimate that in 2008, 1.4 million pregnant women worldwide were infected with syphilis, 80% of whom had attended antenatal care services. The percentage of pregnant women tested for syphilis and adequately treated, ranges from 30% for Africa and the Mediterranean region to 70% for Europe. In 2008, syphilis infections in pregnant women caused approximately 215,000 stillbirths, 90,000 neonatal deaths, 65,000 preterm or low birth weight babies, and 150,000 babies with congenital infections [7].

Therefore, it is important to realize that despite antenatal care programmes, a fairly sensitive point-of-care syphilis test, and effective treatment options, syphilis continues to be an important cause of adverse outcomes of pregnancy, including considerable numbers of perinatal deaths and disabilities.

Urethral discharge in men is mainly caused by Neisseria gonorrhoeae and Chlamydia trachomatis and, with the former, the discharge can be profuse and milky but the latter may cause only a little watery discharge, dysuria or regularly no symptoms at all. If symptoms persist after treatment of these two organisms an infection with Trichomonas vaginalis could be postulated and this can be treated accordingly.

There is increasing concern about the resistance of Neisseria gonorrhoeae for the antibiotics commonly used around the world. In the last 10 years a high level of resistance to fluoroquinolone emerged and only third-generation cephalosporins now remain recommended as first line treatment regimen for gonococcal infections. There are reports of decreased susceptibility in N. gonorrhoeae to ceftriaxone and cefixime and also treatment failure from countries in South and East Asia and this has now spread to Australia, Europe and Canada [8]. The majority of reports are from developed countries and we are ill-informed about the situation in resource-constrained settings as surveillance data are lacking. So multi-drug resistance gonococci may be a problem in the near future and initial treatment with two drugs is already recommended in the United States and the United Kingdom[9].

Syndromic case management of vaginal discharge and lower abdominal pain is complicated by the lack of a clear definition of what constitutes an abnormal vaginal discharge in quantity, colour or odour and the multiple causes of lower abdominal pain in sexually active women. An infection of the vaginal mucosa is commonly caused by Trichomonas vaginalis alone or together with bacterial vaginosis (BV) or a yeast infection. If the local prevalence of N. gonorrhoeae or C. trachomatis is high a mucopurulent cervicitis may cause vaginal discharge and treatment for these organisms should be considered.

Women with lower abdominal pain accompanied by cervical excitation tenderness or vaginal discharge should be managed for pelvic inflammatory disease (PID). Infectious organisms that are commonly involved include Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and anaerobic bacteria, and perhaps Mycoplasma. When women provide a history of a missed or overdue period, recent delivery, abortion, and physical examination indicates abdominal guarding, abnormal vaginal bleeding, or an abdominal mass, a gynaecological referral is due.

Human Papilloma Virus infections are the cause of genital warts but more importantly, of cervical cancer. Cervical cancer is the 2nd most common cancer among women, worldwide, and the great majority occurs in developing countries. HIV co-infection and the lack of effective screening programmes are contributing factors to this problem. Since several years we have two vaccines against HPV types [6,11], 16, 18 that are used as a preventive strategy [10]. Both vaccines have been shown to be highly immunogenic and effective in prevention of incidence and persistent HPV infections that could lead to the development of precancerous lesions. Many countries have developed their own individual vaccine schedules. However, HPV-vaccination is preferably provided to individuals that have not yet become sexually active. The high cost of the vaccines and the challenges of immunizing girls aged 9 to 13 years have been barriers to introduction in less affluent countries. The first countries to get support for HPV vaccines through demonstration programmes were recently announced namely Ghana, Kenya, Madagascar, Malawi, Niger, Sierra Leone, Tanzania and Lao PDR. Most of them will begin introducing the vaccines this year protecting girls aged 9 to 13, mainly through vaccination in schools. By 2020, it is estimated that over 30 million girls will be immunized and this is exciting news [11].

Effective cervical cancer screening programmes in developing countries are lacking because of the weak health care infrastructure that is not able to offer regular pelvic examination of women or cytology screening, shortage of health care workers, and the use of the sensitive HPV DNA testing is completely out of reach. In developing countries there are also different uptake rates of screening among women of diverse ethnic and socio-economic groups so that e.g. in the USA there are significant differences in incidence and mortality rates between white and non-white women [12]. With these HPV vaccination programmes we have the potential to reduce the cervical cancer burden among women of different ethnic groups or socio-economic status and decrease the incidence and mortality of cervical cancer in developing countries.

Conclusions

The role of traditional STI in increasing the risk of HIV acquisition has led to more interventions trying to control these infections. However, despite the availability of active drugs and e.g. syndromic case management traditional STI still cause high levels of morbidity and mortality. The many reasons for this include lack of education, sex work, alcohol use, unsafe sex, unfriendly health services etc. The increased demand for HIV care programmes can only be reached through decentralization to peripheral health care units that need trained staff and support through guidelines and a reliable supply of essential drugs. Nevertheless, STI prevention efforts should remain an important priority and despite the fact that medical male circumcision and pre-exposure prophylaxis are effective in reducing HIV incidence, we should not neglect the issues mentioned above like unsafe sex and alcohol use that still continue to hamper the prevention of STI.

Reference

Full list of references can be obtained from the author.

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