Sexually transmitted infections can be split into four basic categories: bacterial, viral, parasitic and fungal.
Many infections do not always manifest symptoms and therefore if you are sexually active it is worth having sexual health checkups at your local clinic. Follow this link for contact details of local HIV Testing Centres and STI Clinics.
Follow these links for brief notes on this page on the following infections:
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There are three main classifications of fungal infections that can be sexually transmitted: Bacterial Vaginosis, Vulvovaginal Candidosis and Trichomoniasis. All of these can be caused by various fungal agents, some of which are naturally present in the human body and so can appear without sexual contact.
Bacterial Vaginosis (BV) is caused by a number of microbes which can flourish when there is a chemical change in the vagina. It is one of the most common reasons for attendance at GUM clinics, and is associated with other STI's such as Chlamydia and Gonorrhoea. It is associated with a number of problems in pregnant women such as miscarriage and low birth weight and with pelvic inflammatory disease and HIV transmission in non pregnant women. In the years between 1990 and 2000, cases of BV increased by 129% and are still rising, the exact number of cases in the population is not known as 50% of infections are asymptomatic and can only be detected by having a sexual heath check.
Vulvovaginal Candidosis/Candidosis or Thrush is most commonly caused by either Candida albicans or Torulopsis glabrata. Although easily treated, the soreness can be uncomfortable and distressing. If left untreated, the symptoms persist and the raw skin can provide an easy entry route for other STI's.
Trichomoniasis is considered to be one of the worlds most common STI's, with an estimated 167 million cases per year. The infection is caused by a flagellate protozoan called Trichomoniasis vaginalis and is associated with premature labour, prostatitis and HIV transmission. The number of cases in females is far higher of that in males; however, this is due to the fact that infection is usually asymptomatic, and is often diagnosed in females who have gone for a cervical smear test.
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The most common parasitic infestation is pubic lice (Phthirus pubis) which, although it is associated with sexual contact, can be passed on by any close contact, including the sharing of bedding/towels etc. The symptoms of an infestation are itching and irritation around the genital area and sometimes it is possible to see the lice. Pubic lice can infect body hair on any part of the body apart from the scalp. Once diagnosed, infestations are easily treated with topical lotions.
Another common parasite that is transmitted through close contact is scabies. This is caused by a mite (Sarcopties scabiei) which burrows under the skin of the host. The symptoms (severe itching) are not caused by the mite itself but by an allergic reaction of the host to the mite's faeces. Again, infestations are easily treated once diagnosed, but scabies may be more persistent than pubic lice.
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Sexually transmitted bacterial infections can be more serious than the previous infections but can usually be treated by antibiotics and, if treated early, will leave no permanent damage.
Chlamydia (Chlamydia Trachomatis) is the most common STI in the UK affecting 1 in 10 sexually active females under the age of 25. Chlamydial infection is important in reproductive health as 10-30% of women infected will develop Pelvic Inflammatory Disease (PID) if the infection is not treated, which can lead to ectopic pregnancy and infertility. PID occurs when the bacteria spread up the reproductive tubes and to the ovaries. Although PID can be caused by other infections, Chlamydia accounts for 40% of all cases. Untreated infection can also lead to painful arthritis in both sexes from swollen joints. It important to have regular check ups, as 50% of males and 70% of females do not show any symptoms of infection and can pass it on without knowing they have it. One sure way to protect yourself is by using a condom correctly during sex, as Chlamydia can only be caught through sexual contact. It is also important to have regular check ups.
Gonorrohoea (Neisseria gonorrhoeae) is the second most common bacterial STI in the UK with 24,958 cases being diagnosed in 2002. Young people are most commonly infected with current rates highest in males aged 20-24 years and females aged 16-19 years. It can only be caught through unprotected sexual contact and some people may not develop any symptoms. For those that do (men show symptoms more frequently than women), symptoms usually include burning pain when passing urine and discharge from the vagina/penis that is yellow or bloody. If left untreated, the effects can be serious, especially for women who can develop PID which can lead to ectopic pregnancy and infertility. It is important to have regular sexual health check ups, as once diagnosed, Gonorrhoea can be treated with antibiotics, usually in a single dose.
Syphilis is caused by a bacteria-like spirochete Treponema pallidum subspecies pallidum It can only be passed through sexual contact or from mother to baby across the placenta. In recent years, cases of syphilis have increased, in part due to outbreaks in the gay communities of Manchester and London which has led to new surveillance in both gay and heterosexual communities. The symptoms of syphilis can vary but usually go through three stages. In the primary stage, painless, but highly infective sores may develop anywhere on the body (though usually at the site of infection). These will clear up on their own in two to six weeks. The secondary stage symptoms usually occur 6 weeks to 6 months after infection and vary considerably but may include a rash on the palms or soles. Late (Tertiary) syphilis occurs 4 or more years after infection and can cause a number of complications including heart problems and dementia (syphilitic encephalitis). The disease can be treated at any point during infection but the long term damage can be irreversible in late syphilis.
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All of these infections are more difficult to cure, and in the case of retroviruses and DNA viruses, maybe incurable.
Genital Warts are caused by the human papillomavirus (HPV). There have been over 90 different viruses identified and about a third of them are sexually transmitted and are one of the most frequently diagnosed STIs. Some people may have no symptoms but most people develop fleshy lumps around the genitals or anus. These will usually disappear if left untreated but this may take years and rarely, the warts can develop in to cauliflower like growths. The virus is transmitted through unprotected sexual contact and can be diagnosed at your local GUM clinic. There can be health implications of genital warts as some types can increase chances of cervical cancer in women. Individual warts can be treated with caustic chemicals depending on their size and location, though there is no cure, and warts can reappear after treatment.
Genital Herpes (Herpes simplex virus, HSV) is caused by one of two viruses, HSV-I and HSV-II. Type II HSV is almost always associated with genital herpes, whereas type I is usually associated with oral herpes (cold sores) but has increasingly been implicated in genital infections. The initial infection is usually the most severe, with blisters and inflammation appearing around the site of infection and the person infected will often feel generally unwell. There is often also a burning sensation when passing urine. The virus then goes in to a dormant phase in the nerve endings at the site of infection, but may reactivate from time to time. It can be contracted through sexual contact (including oral sex with someone who has a cold sore) and is at it most infectious when the person infected has sores, though it is possible to have no symptoms and still pass on the virus. The diagnosis of herpes involves taking a swab from the sore at your local GUM clinic, and you will also be tested for other STI's. Although incurable, the first outbreak can be treated with antivirals to lessen the symptoms and duration.
The most common sexually transmitted Hepatitis virus is Hepatitis B Virus (HBV). The virus can only be transmitted though contact with infected blood and can be vaccinated against. Once infected, the virus has an incubation period of 40 to 160 days and many people will not have any symptoms while some people may experience flu like symptoms, nausea and vomiting. During the acute phase, many people may continue to have no symptoms while others may develop severe symptoms which may include abdominal discomfort and jaundice and in some cases, death. After this phase, 9 out of 10 adults will clear the infection from their bodies. For those that don't and leave the infection untreated, after 6 months it develops in to chronic carrier state where the individual may not have any symptoms but remains infectious and risks developing cirrhosis of the liver and liver cancer. These individuals are likely to have the infection for the rest of their lives and are also more likely to have Hepatitis D co infection or super infection. However, a vaccine which all at risk individuals should have, can be obtained from your local GUM Clinic as can a check for HBV infection.
A similar blood borne virus is Hepatitis C (HVC). Unusually for blood-borne viruses, sexual transmission is thought to be relatively rare though as always, there is a risk and those with a new partner or a partner that is infected should always use a condom. The virus effects different people different ways but the most common reported symptoms are similar to that of HBV. 15-20% of people naturally clear the virus from their system in 6 months, for those that don't, it remains a long term chronic condition that can last a life time. Chronic Hep C infection can lead to cirrhosis and liver cancer, but can be treated with interferon and anti-viral drugs.
Hepatitis A infection is present in the blood and faeces of the infected individual. Transmission occurs through the faeces -oral route though it can also occur through contact with infected blood. Symptoms are again similar to the other hepatitis viruses and can be quite severe. There is a vaccine available from your local GUM clinic and all individuals at risk should be vaccinated and regularly tested.
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