Sexually transmitted disease

A serious health threat of widespread concern

Sexually transmitted diseases (STDs) are amongst the most common infectious diseases globally. The term sexually transmitted disease encompasses a wide range of infections caused by bacteria, viruses and parasites through sexual intercourse (vaginal, oral or anal) with an infected individual. Such infections include contamination with HIV, syphilis, hepatitis, herpes and the human papilloma virus (HPV). They represent a serious health threat given their potentially serious complications and the fact they increase susceptibility to other infections. Highly sexually active people with multiple sexual partners, those who do not use condoms, drug abusers and commercial sex workers are at high risk. Symptoms should be checked regularly as these infections can have severe long-term consequences for the individual’s and their partner’s health.

Today, in the United States, one in four teenagers becomes infected, and by the age of 25 as many as one in two of all sexually active young adults are affected.1 Likewise in Europe, sexually active young people are most likely to contract an STD, whereas homosexual men comprise the largest group of new HIV cases detected per year.2 A new challenge is the rise of syphilis in Europe, primarily amongst men who are highly sexually active. Left untreated, syphilis causes significant complications, although it can be successfully treated with antibiotics. However, in many countries, traditionally in the developing and emerging regions, a failure to diagnose and treat lowers the chance of containment.

Due to a decline in awareness, in particular amongst young people, many individuals are not well informed or even aware that they could be the carrier of an STD. Adolescents and young adults account for almost 50 percent of all newly acquired sexually transmitted diseases.1 They are more likely to engage in high-risk sexual behaviour, including a lack of condom use, having multiple sexual partners, regularly having new sexual partners, and having sexual relations with persons of unknown disease risk. With the exception of HIV/AIDS, general awareness of sexually transmitted diseases amongst young people is rather low, and knowledge does not necessarily translate into changed sexual behaviour. It therefore remains important for adolescents to receive a more comprehensive sexual education including hard-hitting campaigns.

Approximately 370,000 babies are born with HIV every year. Without appropriate treatment, more than half of these children will die. Another prominent cause of infant mortality is untreated maternal syphilis, which still accounts for more than half a million stillbirths.

However these deaths could be prevented through routine detection and treatment of syphilis by prenatal care. Rising rates of syphilis among pregnant women in the United States have increased the number of babies born with syphilis. An evaluation for risk factors and universal screening of pregnant women for syphilis is urgently needed and should become a standard of care.

Rates of sexually transmitted diseases amongst homosexual men are high and have been increasing, principally due to the higher risk sexual behaviour which is prevalent in this target group. They are also more likely to be carriers of early syphilis and HIV. Medical guidelines recommend healthcare professionals undertake presumptive treatment of sexual contacts of individuals with syphilis. For this reason, early and regular testing for syphilis infection is vital as it is the only way to establish contamination. In the case of HIV, it should be obligatory to be tested at least once a year.

Injecting drug users are at increased risk of contracting an STD through the use and sharing of contaminated needles, the practice of high-risk sexual behaviour owing to lowered inhibitions, and having sexual relations with other drug users at a similarly high level of risk. Only limited information is published on the proportion and risk factors of syphilis infections associated with illicit drug abuse. However, there is clearly a need for screening among drug users.


Sexually transmitted diseases in brief


Transmission is through intimate sexual contact. Additionally, several sexually transmitted diseases can also be transferred from mother to child during pregnancy and childbirth. Contracting a sexually transmitted disease can increase the risk of HIV infection three-fold or more.

Risk factors include high-risk sexual activity, young age, early onset of sexual activity, lack of condom use, having multiple sexual partners, and existing infection with a sexually transmitted disease.

Groups at high risk of acquiring and transmitting sexually transmitted diseases include young adolescents and adults, pregnant women, men who have sex with men, and injecting drug users.

sexually transmitted diseases fig1

  1. U.S. Department of Health and Human Services. Centers for Disease Control and Prevention. Transmitted Disease Surveillance. Washington 2010.
  2. European Centre for Disease Prevention and Control (ECDC). Sexually transmitted infections in Europe. Stockholm 2011.
  3. American Foundation for AIDS Research (amfAR). Eradicating Mother-to-Child HIV Transmission: Where We Are and Where We Need to Go. amfAR-Sponsored Congressional Briefing. Last access January 2014.