Type: Bacterial
Incubation period: 1–3 weeks, up to 6 weeks
Sample site: Urine 

Chlamydia is the most common curable STI diagnosed in the UK. Often asymptomatic, anyone who is sexually active is considered to be at increased risk of chlamydia infection.

It is the most commonly recognised,screened and treated of all STI’s.

It's passed on through unprotected sex (sex without a condom) and is particularly common in sexually active teenagers and young adults.

If you're a woman, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year, and when you have sex with new or casual partners.

If you're a man, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year if you are not using condoms with new or casual partners.

Symptoms of chlamydia
Most people with chlamydia do not notice any symptoms and do not know they have it.

If you do develop symptoms, you may experience:

pain when peeing
unusual discharge from the vagina, penis or bottom
in women, pain in the tummy, bleeding after sex and bleeding between periods
in men, pain and swelling in the testicles
If you think you're at risk of having a sexually transmitted infection (STI) or have any symptoms of chlamydia, visit a GP, community contraceptive service or local genitourinary medicine (GUM) clinic to get tested.


How do you get chlamydia?
Chlamydia is a bacterial infection. The bacteria are usually spread through sex or contact with infected genital fluids (semen or vaginal fluid).

You can get chlamydia through:

unprotected vaginal, anal or oral sex
sharing sex toys that are not washed or covered with a new condom each time they're used
your genitals coming into contact with your partner's genitals – this means you can get chlamydia from someone even if there's no penetration, orgasm or ejaculation
infected semen or vaginal fluid getting into your eye
It can also be passed by a pregnant woman to her baby.

Chlamydia cannot be passed on through casual contact, such as kissing and hugging, or from sharing baths, towels, swimming pools, toilet seats or cutlery.

Is chlamydia serious?
Although chlamydia does not usually cause any symptoms and can normally be treated with a short course of antibiotics, it can be serious if it's not treated early on.

If left untreated, the infection can spread to other parts of your body and lead to long-term health problems, especially in women.

In women, untreated chlamydia can cause pelvic inflammatory disease (PID), ectopic pregnancy and infertility.

In men, in rare cases, chlamydia can spread to the testicles and epididymis (tubes that carry sperm from the testicles), causing them to become painful and swollen. This is known as epididymitis or epididymo-orchitis (inflammation of the testicles).

It can also sometimes cause reactive arthritis in men and women.

This is why it's important to get tested and treated as soon as possible if you think you might have chlamydia.

Getting tested for chlamydia
Testing for chlamydia is done with a urine test or a swab test.

You do not always need a physical examination by a nurse or doctor.

Anyone can get a free and confidential chlamydia test at a sexual health clinic, a genitourinary medicine (GUM) clinic or a GP surgery.

In England, if you're a woman under 25 years old, you may be offered a chlamydia test when you visit some health services, for example a pharmacy or GP. This offer is part of the National Chlamydia Screening Programme (NCSP).

If you're offered a chlamydia test you should consider taking it.

If you're a woman, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year, and when you have sex with new or casual partners.

If you're a man, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year if you are not using condoms with new or casual partners.

You can also buy chlamydia testing kits to do at home.

How chlamydia is treated
Chlamydia can usually be treated easily with antibiotics.

You may be given a course of doxycycline to take for a week or azithromycin to take once a day for 3 days.

If you have doxycycline, you should not have sex (including oral sex) until you and your current sexual partner have finished treatment.

If you have azithromycin, you should wait 7 days after treatment before having sex (including oral sex).

It's important that your current sexual partner and any other recent sexual partners you have had are also tested and treated to help stop the spread of the infection.

Under-25s who have chlamydia should be offered another test 3 to 6 months after being treated.

This is because young adults who test positive for chlamydia are at increased risk of catching it again.

Sexual health or genitourinary medicine (GUM) clinics can help you contact your sexual partners.

Either you or the clinic can speak to them, or they can be sent a note advising them to get tested.

The note will not have your name on it, so your confidentiality will be protected.

Preventing chlamydia
Anyone who's sexually active can catch chlamydia.

You're most at risk if you have a new sexual partner or do not use a barrier method of contraception, such as a condom, when having sex.

You can help to prevent the spread of chlamydia by:

using a condom every time you have vaginal or anal sex
using a condom to cover the penis during oral sex
using a dam (a piece of thin, soft plastic or latex) to cover the female genitals during oral sex or when rubbing female genitals together
not sharing sex toys
If you do share sex toys, wash them or cover them with a new condom between each person who uses them.

Source:
TDL
NHS

Type: Bacterial
Incubation period: 2–7 days, up to 1 month
Sample site: Urine 

Gonorrhoea is a sexually transmitted infection (STI) caused by bacteria called Neisseria gonorrhoeae or gonococcus. It used to be known as "the clap".

How gonorrhoea is spread
The bacteria that cause gonorrhoea are mainly found in discharge from the penis and in vaginal fluid.

Gonorrhoea is easily passed between people through:

unprotected vaginal, oral or anal sex
sharing vibrators or other sex toys that have not been washed or covered with a new condom each time they're used
The bacteria can infect the entrance to the womb (cervix), the tube that passes urine out of the body (urethra), the rectum and, less commonly, the throat or eyes.

The infection can also be passed from a pregnant woman to her baby. If you're pregnant and may have gonorrhoea, it's important to get tested and treated before your baby is born.

Without treatment, gonorrhoea can cause permanent blindness in a newborn baby.

Gonorrhoea is not spread by kissing, hugging, swimming pools, toilet seats or sharing baths, towels, cups, plates or cutlery. The bacteria cannot survive outside the human body for long.

Symptoms of gonorrhoea
Typical symptoms of gonorrhoea include a thick green or yellow discharge from the vagina or penis, pain when peeing and, in women, bleeding between periods.

But around 1 in 10 infected men and almost half of infected women do not experience any symptoms.

Getting tested
If you have any of the symptoms of gonorrhoea or you're worried you may have an STI, you should visit a sexual health clinic for a sexual health test.

Gonorrhoea can be easily diagnosed by testing a sample of discharge picked up using a swab. In men, testing a sample of urine can also diagnose the condition.

It's important to get tested as soon as possible because gonorrhoea can lead to more serious long-term health problems if it's not treated, including pelvic inflammatory disease (PID) in women or infertility.

Treating gonorrhoea
Gonorrhoea is usually treated with a single antibiotic injection (usually in the buttocks or thigh). With effective treatment, most of your symptoms should improve within a few days.

It's usually recommended you attend a follow-up appointment a week or 2 after treatment so another test can be carried out to see if you're clear of infection.

You should avoid having sex until you have been told you no longer have the infection.

Previous successful treatment for gonorrhoea does not make you immune to catching it again.

Who's affected
Anyone who's sexually active can catch gonorrhoea, particularly people who change partners frequently or do not use a barrier method of contraception, such as a condom, when having sex. (See Your contraception guide.)

Gonorrhoea is the second most common bacterial STI in the UK after chlamydia.

In 2019, more than 70,000 people were diagnosed with gonorrhoea in England, with most cases affecting gay, bisexual and other men who have sex with men.

Preventing gonorrhoea
Gonorrhoea and other STIs can be successfully prevented by using appropriate contraception and taking other precautions, such as:

using male condoms or female condoms every time you have vaginal sex, or male condoms during anal sex
using a condom to cover the penis or a latex or plastic square (dam) to cover the female genitals if you have oral sex
not sharing sex toys, or washing them and covering them with a new condom before anyone else uses them

Source:
TDL
NHS

Type: Bacterial
Incubation period: Symptoms develop at 1–3 weeks
Sample site: Urine

Mycoplasma genitalium (M.gen) is an important sexually transmitted pathogen detectable only by NAAT. M.gen lacks a cell wall and has limited treatment options. It spontaneously develops resistance to antimicrobials. BASHH recommends treatment with Resistance Guided Therapy – testing for M.gen with macrolide resistance determination. M.gen cannot be cultured for diagnostic testing. M.gen prevalence is higher than GC, and in some populations can be similar to CT.

M.gen risk factors are similar to CT and consider testing M.gen in all males with non-GC urethritis and all individuals with signs or symptoms of PID, cervicitis, endometritis, associated infertility, ano-rectal condition or epididymo-orchitis. Partner testing is advised for current partners only. Rectal infections are common, and appear to be an important reservoir for resistance. BASHH guidance – all patients must return for test of cure at 3-5 weeks.

Source: TDL

Type: Bacterial
Incubation period: Symptoms develop at 1–3 weeks
Sample site: Urine

U. Urealyticum and parvum are strains of bacteria that can lead to urinary tract infection and pelvic inflammation. Usually asymptomatic, it is part of the normal genital flora of both men and women. It is found in about 70% of sexually active humans. In males with lower sperm quality, ureaplasma infection could lead to a more pronounced decreased in some seminal parameters and compromise sperm motility.

Source: TDL

Type: Parasitic
Incubation period: 4–28 days, many patients are asymptomatic carriers
Sample site: Urine

Trichomoniasis is a sexually transmitted infection (STI) caused by a parasite called Trichomonas vaginalis (TV).

Symptoms of trichomoniasis
Symptoms of trichomoniasis usually develop within a month of infection.

But up to half of all people will not develop any symptoms (though they can still pass the infection on to others).

The symptoms of trichomoniasis are similar to those of many other sexually transmitted infections (STIs), so it can sometimes be difficult to diagnose.

Symptoms in women
Trichomoniasis in women can cause:

abnormal vaginal discharge that may be thick, thin or frothy and yellow-green in colour
producing more discharge than normal, which may also have an unpleasant fishy smell
soreness, swelling and itching around the vagina – sometimes the inner thighs also become itchy
pain or discomfort when passing urine or having sex

Symptoms in men
Trichomoniasis in men can cause:

pain when peeing or during ejaculation
needing to pee more frequently than usual
thin, white discharge from the penis
soreness, swelling and redness around the head of the penis or foreskin

When to get medical advice
See a GP or go to your local sexual health clinic (sometimes called a GUM clinic) if you develop any of the symptoms of trichomoniasis or you think you may be infected.

Trichomoniasis can usually be diagnosed after an examination of the genitals and a laboratory test carried out on a swab taken from the vagina or penis.

If the test shows you have trichomoniasis, it's important that your current sexual partner and any other recent partners are also tested and treated.

How do you get trichomoniasis?
Trichomoniasis is caused by a parasite called Trichomonas vaginalis.

In women, this parasite mainly infects the vagina and the urethra (the tube that carries urine out of the body).

In men, the infection most commonly affects the urethra, but the head of the penis or prostate gland – a gland near the bladder that helps produce semen – can become infected in some cases.

The parasite is usually spread by having sex without using a condom.

It could also be spread by sharing sex toys if you do not wash them or cover them with a new condom before use.

You do not have to have many sexual partners to catch trichomoniasis. Anyone who's sexually active can catch it and pass it on.

Trichomoniasis is not thought to be passed on through oral or anal sex.

You also cannot pass on trichomoniasis through:

kissing or hugging
sharing cups, plates or cutlery
toilet seats
The best way to prevent trichomoniasis is to have safe sex. This means always using a condom when having sex, covering any sex toys you use with a condom, and washing sex toys after use.

Treating trichomoniasis
Trichomoniasis is unlikely to go away without treatment, but it can be effectively treated with antibiotics.

Most men and women are treated with an antibiotic called metronidazole, which is usually taken twice a day for 5 to 7 days.

It's important to complete the whole course of antibiotics and avoid having sex until the infection clears up to prevent reinfection.

Your current sexual partner and any other recent partners should also be treated.

Complications of trichomoniasis
Complications of trichomoniasis are rare, although some women with the infection may be at an increased risk of further problems.

If you're infected with trichomoniasis while you're pregnant, the infection may cause your baby to be born prematurely or have a low birthweight.

SOURCE: 
NHS 
TDL

Type: Bacterial
Incubation period: Imbalance of normal flora
Sample site:  Urine

Gardnerella vaginalis is a bacterium rather than a sexually transmitted infection. It is part of the normal vaginal flora but, when the normal balance of bacteria in the vagina is disrupted, it can flourish and overgrow leading to bacterial vaginosis. Does it matter if it not an STI? Yes, because it can be characterised by a fishy smelling, white vaginal discharge, itching, burning, and irritation, and there are some known pregnancy and pelvic inflammatory conditions associated with Gardnerella as well as a higher risk of getting other STI’s.

In a patient with signs and symptoms suggestive of bacterial vaginosis detection of G. vaginalis provides supportive evidence of bacterial vaginosis. It can, however, be detected in asymptomatic individuals and it can also be absent in patients with bacterial vaginosis which has been caused by overgrowth of other similar organisms such as Mobiluncus and Atopobium species. Results should be interpreted in line with patient’s clinical symptoms and microscopy.

Source: TDL