Sexually Transmitted Infections

A sexually transmitted infection (STI), sexually transmitted disease (STD) or venereal disease (VD) is a category of diseases and infections either passed on through sexual intercourse, or caused by infections past on through intercourse, ranging from penetrative intercourse involving the vagina or anus, or oral intercourse. STIs are amongst the most widely known disease and infections.

As a matter of public awareness, STIs are some of the most widely known and generally understood diseases and disorders, in as much as large amount of information have been disseminated amongst the global population about a wide variety of these diseases and infections. STIs are perhaps the most publicised diseases and infections in the media, and have been the focus of several high profile films, books and television shows.

In recent years large efforts have been made to reduce the spread of most STIs, with campaigns on a national and global level focusing on such infections as HIV, syphilis and gonorrhoea. The World Health Organisation has undertaken a number of high profile campaigns that have seen varying but mostly positive success to tackle the spread of HIV, syphilis and other STIs.

Diagnosis and treatment of STIs varies greatly depending on the type of infection or disease a person has. STIs range in form and can be present as basterial, fungal, or viral infections, as well as parasitical and protozoal infestations. In some cases it may be as simple as observation, where in others the patient may be required to undergo noninvasive or invasive testing, blood tests, smear tests or other such tests. Culturing may also be used. Treatment can include simple courses of antiviral and antibacterial medication, topical creams or injections, or may require lifelong medication (as is the case with HIV/AIDS).

Most STIs are generally not life threatening in people with healthy immune systems, however all STIs can result in complications - even if rarely - that can lead to permanent health problems and in some cases death. HIV/AIDS is perhaps the mostly widely known and dangerous of all STIs, although other STIs should not be underestimated as matters of grave concern.

Syphilis

Syphilis is a well-known sexually transmitted infection. It is primarily transmitted through sexual contact, although it may also be transmitted from an infected mother to the foetus during pregnancy (congenital syphilis). 

Syphilis is believed to have infected around 15 million people globally, with more than 90% of cases being in the developing world. Despite a decline in infection in the 1940s due to improved availability of penicillin, rates of infection have increased since 2000 which has been attributed to unsafe sexual practices, increased promiscuity, prostitution, and decreasing use of condoms.

Human papillomavirus (HPV)

Human papillomavirus (HPV) is a virus of the papillomavirus type. HPVs infect only the keratinocytes of the skin or mucous membranes. Most HPV infections cause no symptoms in most people.

There are more than 30 to 40 types of HPV that are typically transmitted through sexual contact. Some may cause genital warts, although most cause no symptoms at all. There are other types of HPV virus - classed as "high risk" - that are different from the ones that cause genital warts, and can progress to precancerous lesions as well as invasive cancers. Nearly all cases of cervical cancer are caused by HPV. 

Human immunodeficiency virus (HIV)

Human immunodeficiency virus (HIV) is a lentivirus – a type of retrovirus – and is the cause of acquired immunodeficiency syndrome (AIDS). AIDS is a condition in humans that leads to progressive failure of the immune system, which allows infections and cancers to thrive.

HIV is one of the most widely known sexually transmitted infections in the world, and is classed as a pandemic infection by the World Health Organisation. Approximately 35 million people have HIV globally, of which 17 million are women and 3.5 million are under the age of 15. Sub-Saharan Africa is considered the area most effected by HIV/AIDS; around 6 million people are infected with HIV/AIDS, and an estimated 66% of all deaths linked to HIV/AIDS globally occurred in this region in 2009, compared with under 200,000 deaths in the US, under 600 in the UK, and 53 in Canada. Despite being a pandemic infection, the spread and morality rates associated with HIV/AIDS have declined in recent years, partly due to improvement in medication and also due to raising global awareness amongst the population. In 2010 there were 1.8 million deaths linked to AIDS, down from 3.1 million in 2001. It is estimated that around 20% of those infected with HIV/AIDS are unaware of the condition. In total HIV/AIDS has led to over 32 million deaths since it was recognised in 1981.

Herpes Simplex

Herpes simplex is a viral disease caused by Herpes simplex type 1 (HSV-1) and type 2 (HSV-2). Herpes infections are categorised into one of several disorders based on the site on infection, ranging from oral herpes (an infection of the mouth), genital herpes (an infection of the genitals), herpes infections of the hand (herpes whitlow), ocular herpes (an infection of the eye), and possibly Bell’s Palsy.

Genital infections caused by the herpes simplex virus (HSV-2) are classed as a sexually transmitted infection. Preventing the spread of HSV-2 is encouraged, and barrier protection is the most reliable method. Despite the wide availability of condoms, many people who suffer HSV-2 infections will not present with symptoms and as such will only find out about their own infection when a partner shows signs of the infection.

Crab louse

Crab louse, or pubic louse - commonly referred to as "crabs" - are a parasitic insect exclusive to humans, that feed exclusively on blood. They are typically found in pubic hair around the genitals, but can also effect other areas of the body with hair, such as eyelashes.

Crab louse can be distinguished from other species of louse by their almost-round body. Adult crab louse are typically 1-2mm long, and are smaller than the body louse and head louse. The term "crab louse" comes from their much thicker two front legs that are equipped with two large claws.

Thrush (Candidiasis)

Thrush (candidiasis) - commonly referred to as a yeast infection - is a fungal infection of any of a number of species of yeasts (candida). These yeast infections can range in severity, from simple and superficial infections of the mouth and genitals, to more severe and potentially life-threatening systemic infections.