Sexually transmissible infections
A sexually transmissible infection (STI) is an infection you can get from any form of sexual activity, including vaginal, anal and oral sex, sharing sex toys, or close sexual contact. If you are sexually active, you should have an STI test at least once a year, even if you practice safe sex.
Many STIs have no symptoms, so people are unaware they are passing on an infection. Some infections appear to go away without treatment, but they stay active in the body and can continue to be passed onto sexual partners. Most STIs are curable, and all are treatable, but if left untreated, some STIs can have long term affects on your body.
Common STIs
Reduce your risk of STIs by having safe sex.
Symptoms associated with STIs
Some of the symptoms you may be experiencing could have many causes, they do not necessarily mean you have an STI. But symptoms need to be taken seriously, have a sexual health check if you experience any of the symptoms below.
Some of the common symptoms associated with STIs include:
Vagina:
- a sore, wart, lump, rash or blister on the genitals
- pain during sex
- pain passing urine
- abnormal vaginal bleeding
- an unusual vaginal discharge
- painful, irregular periods and/or bleeding between periods or after sex.
Penis/testicles:
- a discharge from the penis
- a sore, wart, lump, rash or blister on the genitals
- an itch or soreness of the penis
- pain passing urine
- painful or swollen testicles
- abdominal pain.
Anus:
- discharge or bleeding
- a sore, wart, lump, blister, rash or swelling
- itching
- pain during bowel movements.
Sexual health checks
As many STIs have no symptoms, it's important to have regular sexual health checks. If you are concerned you have an STI, talk about it with your local doctor, family planning clinic, or sexual health clinic and avoid having sex until you have received medical advice.
Further information
Animations on sexually transmissible infections
Blood cannot enter your body through the skin but it can enter through your bloodstream. This can be through a break or microscopic tear in the skin or lining of the mouth, vagina, penis or anus.
Blood-to-blood contact with another person is risky as blood can carry viruses.
Once inside the body contaminated blood will mix with your blood and may transfer viruses like HIV, Hepatitis B and Hepatitis C.
You can take protective measures to avoid blood-borne viruses like HIV and other STIs.
Use condoms and water-based lubricant during sex.
Don’t inject with used injecting equipment.
Avoid getting piercings and tattoos where they may be using unsterile equipment or in an unsterile environment.
And do not share personal hygiene equipment like toothbrushes, tweezers or razor blades.
If you think you may have been exposed to a blood-borne virus you should see a health care provider.
Chlamydia is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal and oral sex. Many people with chlamydia do not have any symptoms so they may not even know they have it.
It is the most common bacterial STI world-wide, especially among people aged 15 to 29 years.
Chlamydia can infect the cervix, throat, anus, eyes, and the urethra, which is a thin tube connected to the bladder through which urine passes. Without proper treatment, chlamydia can spread further through the body, infecting the uterus and the fallopian tubes. These are the hollow tubes that connect the uterus to the ovaries.
When the body detects an STI, the immune system tries to destroy the infection.
There are often no symptoms during this immune response, but sometimes the area can become inflamed and sore.
As the STI is killed and immune system cells die off, they sometimes form a discharge at the opening of the vagina.
The inflammation that occurs in the cervix, uterus or fallopian tubes is called Pelvic Inflammatory Disease or PID.
PID can present as mild abdominal pain which can be missed if women mistake it for period pain. It can also cause pain or bleeding during or after sex. PID can also cause scarring which can block the fallopian tubes and may result in infertility, as sperm released during ejaculation cannot travel through the tubes to fertilise the egg.
Damaged fallopian tubes can impact on the process of moving a fertilised egg through the tube towards the uterus at the start of pregnancy.
The egg may then attach itself to the fallopian tube where it begins to grow.
This is called an ectopic pregnancy and can be very dangerous.
Chlamydia can also be passed from mother to baby during delivery, causing an infection in the newborn’s eyes.
Chlamydia and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify your sexual partners if you are diagnosed with an STI.
Chlamydia is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal and oral sex. Many people with chlamydia do not have any symptoms so they may not even know they have it.
It is the most common bacterial STI world-wide, especially among people aged 15 to 29 years.
Chlamydia commonly infects the urethra, but can also occur in the throat, anus and even the eyes.
As the body’s immune system fights the STI, dead cells from the immune system, and cells that die as a result of the infection are occasionally passed out of the body as a clear or milky discharge or pus.
Other symptoms can be stinging pain or burning when urinating, or swollen and painful testes.
If left untreated, chlamydia can continue further into the reproductive system, affecting the seminal vesicles, vas deferens, epididymis and the testicles.
Because the vas deferens and the seminal vesicles are so small, any scarring as a result of the infection can contribute to reduced sperm counts and infertility.
Untreated chlamydia can also cause chronic epididymitis, which is persistent inflammation and pain in the testes that can be difficult to treat.
Chlamydia and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify your sexual partners if you are diagnosed with an STI.
Gonorrhoea is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal, and oral sex.
It can infect the cervix, rectum, throat, and even the eyes. It can also infect the urethra. This is the thin tube connected to the bladder through which urine passes.
Without treatment, gonorrhoea can spread into the uterus and the fallopian tubes, which are tubes connecting the uterus to the ovaries.
When the body detects an STI, the immune system tries to destroy the infection.
There are often no symptoms during this immune response, but sometimes the area can become inflamed and sore.
As the STI is killed and immune system cells die off, they sometimes form a discharge at the opening of the vagina.
The inflammation that occurs in the cervix, uterus or fallopian tubes is called Pelvic Inflammatory Disease or PID.
PID can present as mild abdominal pain which can be missed if women mistake it for period pain. It can also cause pain or bleeding during or after sex. PID can also cause scarring which can block the fallopian tubes and may result in infertility, as sperm released during ejaculation cannot travel through the tubes to fertilise the egg.
Damaged or scarred fallopian tubes can also impact on the process of moving a fertilised egg through the tube towards the uterus at the start of pregnancy.
The egg may then attach itself to the fallopian tube where it begins to grow. This is called an ectopic pregnancy and can be very dangerous.
Gonorrhoea can also be passed from mother to baby during delivery, causing an infection in the newborn’s eyes.
Some types of gonorrhoea are resistant to antibiotics and can therefore be difficult to treat. If diagnosed and treated for gonorrhoea, it is important to have a follow up visit with a health provider to check that the gonorrhoea has been cleared.
Gonorrhoea and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify sexual partners if you are diagnosed with an STI.
Gonorrhoea is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal and oral sex.
It can infect the urethra, anus, throat, and even the eyes.
Gonorrhoea travels up the urethra where it can cause pain or a burning sensation while urinating, although some people will have no symptoms.
As the body’s immune system fights the STI, dead cells from the immune system, and cells that die as a result of the infection are sometimes passed out as a discharge or pus.
If left untreated, gonorrhoea can also continue further into the reproductive system, affecting the seminal vesicles, vas deferens, epididymis and the testicles.
Because the vas deferens and the seminal vesicles are so small, any scarring as a result of infection can contribute to reduced sperm count and infertility. If left untreated, gonorrhoea can cause chronic epididymitis, and prostatitis, which is an inflammation of the prostate gland.
Some types of gonorrhoea are resistant to antibiotics and can therefore be difficult to treat. If diagnosed and treated for gonorrhoea it is important to have a follow up visit with a health provider to check that the gonorrhoea has been cleared.
Gonorrhoea and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify sexual partners if you are diagnosed with an STI.
Syphilis is a highly infectious sexually transmissible infection or STI, that is passed on during intimate skin-to-skin contact or vaginal, anal or oral sex with an infected person. It has several stages and can be infectious over a long time.
The first signs of syphilis are often sores or ulcers on or inside the genitals, mouth, or throat about 2-3 weeks after infection. They can also develop earlier, much later or don’t develop at all.
This first stage of infection is called primary syphilis and the sores, called chancres, can be any size or shape.
The ulcers are often painless, don’t bleed and can feel like a hard button on your skin. You may not notice them, especially if they are on anal skin, inside the anus, the cervix, or in the mouth.
If there is no treatment, the ulcers usually heal within a few weeks but the infection does not go away.
Two to six months after getting infected, the secondary stage of syphilis occurs.
Symptoms may include a flu-like illness, a rash on the torso, palms, and soles of the feet, swollen glands, wart-like lumps around the moist areas of the body, and hair loss.
The rash looks like rough, red or brown spots but these are usually not itchy.
Some people also get headaches, tiredness and pains in the bones, muscles and joints.
You can feel quite unwell during this stage.
When the body detects an STI, the immune system tries to destroy the infection.
If you do not get treatment, the immune response can cause secondary symptoms which can come and go for up to a year after the initial infection.
Even when these symptoms go away, you are still infectious. Some people will never develop symptoms and will only learn that they have syphilis after having a blood test.
After two years of infection you are no longer infectious to other people. This stage of the infection is called late latent syphilis and treatment at this stage is very important to prevent long-term consequences. For some people, untreated syphilis can turn into tertiary syphilis, sometimes up to 20 years after first infected.
Tertiary syphilis can cause serious problems with nerves, and the large vessels near the heart. Blindness, numbness and brain damage can also occur.
It is very important for all women to be tested for syphilis during pregnancy as an infected woman can pass syphilis onto her unborn baby through the placenta. This is called congenital syphilis and can be a severe, disabling and life-threatening infection for babies. The earlier syphilis is treated during the pregnancy, the lower the risk of the baby being affected.
Syphilis can also increase the risk of transmission of HIV and other STIs.
Syphilis can be easily treated with injections of antibiotics.
Syphilis and other STIs can be prevented by using condoms and water-based lubricant during sex, using sterile injecting equipment, and having regular sexual health check ups. If you are diagnosed with syphilis you must ensure that you or your health provider notify your sexual partners so that they can get tested and treatment if needed.
Syphilis is a highly infectious sexually transmissible infection or STI, that is passed on during intimate skin-on-skin contact or vaginal, anal or oral sex with an infected person. It has several stages and can be infectious over a long time.
The first signs of syphilis are often sores or ulcers on or inside the genitals, mouth, or throat about 2-3 weeks after infection. They can also develop earlier, much later or don’t develop at all.
This first stage of infection is called primary syphilis and the sores, called chancres, can be any size or shape.
The ulcers are often painless, don’t bleed and can feel like a hard button on your skin. You may not notice them, especially if they are on anal skin, inside the anus or inside the mouth.
If there is no treatment, the ulcers usually heal within a few weeks but the infection does not go away.
Two to six months after getting infected, the secondary stage of syphilis occurs.
Symptoms may include a flu-like illness, a rash on the torso, palms, and soles of the feet, swollen glands, wart-like lumps around the moist areas of the body, and hair loss.
The rash looks like rough, red or brown spots but these are usually not itchy.
Some people also get headaches, tiredness and pains in the bones, muscles and joints.
You can feel quite unwell during this stage.
When the body detects an STI, the immune system tries to destroy the infection.
If you do not get treatment, the immune response can cause secondary symptoms which can come and go for up to a year after the initial infection.
Even when these symptoms go away you are still infectious. Some people will never develop symptoms and will only learn that they have syphilis after having a blood test.
After two years of infection, you are no longer infectious to other people. This stage of the infection is called late latent syphilis and treatment at this stage is very important to prevent long-term consequences. For some people, untreated syphilis can turn into tertiary syphilis, sometimes up to 20 years after first infected.
Tertiary syphilis can cause serious problems with nerves, the brain and the large vessels near the heart. Blindness, numbness and brain damage can also occur.
If your partner is pregnant, remind her that it is very important for all women to be tested for syphilis during pregnancy as an infected woman can pass syphilis onto her unborn baby through the placenta.
This is called congenital syphilis and can be a severe, disabling and life-threatening infection for babies. The earlier syphilis is treated during the pregnancy, the lower the risk of the baby being affected.
Syphilis can also increase the risk of transmission of HIV and other STIs.
Syphilis can be easily treated with injections of antibiotics.
Syphilis and other STIs can be prevented by using condoms and water-based lubricant during sex, using sterile injecting equipment, and having regular sexual health check ups. If you are diagnosed with syphilis you must ensure that you or your health provider notify your sexual partners so that they can get tested and treatment if needed.
Human Immunodeficiency Virus (HIV) is transmitted from person to person through blood, semen, vaginal fluids and breastmilk. HIV can enter the body through the lining of the vagina, penis, or anus during sex without a condom, through sharing injecting equipment or through breastfeeding.
Once it is in the body, HIV travels through the blood and targets key elements of the immune system called T cells.
HIV particles search and find special receptors called CD4 receptors on the outside of the T cell. The virus then merges with the T cell and begins to insert its genetic material.
HIV genetic material, RNA, is converted to make a DNA copy of HIV RNA to be able to insert itself into the genetic material of the T cell.
The converted material is then able to insert itself into the genetic material of the T cell to make HIV provirus.
Now the virus uses the reproductive cycle of the T cell to make copies of its own genetic structure.
The new copies of the HIV RNA create new HIV virus particles that exit the cell and recommence the reproductive cycle in another cell.
The HIV reproductive cycle has seriously damaged the T cell, which will now die.
If a person living with HIV does not take treatment to prevent the ongoing destruction of the T cells and HIV replication, their immune system may eventually break down and they can develop Acquired Immune Deficiency Syndrome, known as AIDS.
While there is no cure for HIV, treatment options have improved so much that people living with HIV can expect to live long, healthy lives. Daily HIV treatment can prevent further virus replication, keep the person well, and prevent onward transmission to others. This treatment is sometimes called Anti-retroviral therapy or ART.
There is also medication available called Post-exposure prophylaxis, or PEP, that may prevent infection after a recent exposure to HIV. HIV negative people can also take HIV medication before they are exposed to the virus to prevent HIV infection. This is called Pre-exposure prophylaxis or PrEP.
HIV and other STIs can be prevented by using condoms and water-based lubricant during sex, using sterile injecting equipment, having regular sexual health check ups and ensuring you or your health provider notify your sexual partners if you are diagnosed with an STI.
Herpes simplex virus or HSV can manifest in the skin around the mouth or around the genitals.
In both cases, herpes can present as a common cold sore or a cluster of small blisters, skin splits or sores. However, in most cases there are no symptoms at all and people often do not know they have it.
Herpes lives in the skin at the site of infection. It can be transmitted when no symptoms are felt or visible. However, the virus is most contagious when sores are present.
Genital herpes is spread with the infected skin on the mouth or genitals coming in contact with the intact skin of the penis, vagina or anus.
Herpes ulcers can form in or on the vagina, anus, penis or scrotum which can then cause pain when going to the toilet. In some cases people can also have flu-like symptoms, tingling, itching or painful blisters or fever. People who develop genital herpes sores are also at a higher risk of contracting HIV.
Herpes can not be cured, although there are antiviral medications available that can help reduce the severity and duration of symptoms or help prevent the outbreaks of sores.
It is very difficult to avoid the herpes virus as it is very common and so many people do not know they have it. You can avoid kissing or sex with someone who has active sores on the mouth, lips, genitals or anal area.
Using condoms can also reduce your likelihood of contracting herpes, however they do not completely prevent it.