Sexually transmitted infections (STIs)

Sexually transmitted infections (STIs), also called sexually transmitted diseases (STDs), are among the most common of the infectious diseases. STIs have, in fact, become more common in Australia in recent years. STIs can be passed from an infected person to others through sexual contact – which includes genital skin-to-skin contact, oral sex and sexual intercourse.

It’s possible for anyone who is sexually active to get an STI, but there are ways you can reduce your risk, such as by practising safe sex. But infections can still happen even if you use condoms. And sometimes there are no symptoms or the symptoms are non-specific, meaning you or your partner may have an STI without knowing it. So, regular sexual health checks are a good idea for anyone who is sexually active, including before you have sex with a new partner.

If you are worried about the possibility of having an STI you should get tested – many infections can be easily treated, and treatment can prevent serious complications as well as further spread of the infection.

How do STIs spread?

STIs are caused by microorganisms – bacteria and viruses mainly. The microorganisms that cause most STIs are found in semen and vaginal secretions, and sometimes also in blood and saliva. Most of these microbes are spread by vaginal, anal or oral sex, but in some cases, such as genital herpes and genital warts, they may be spread through skin-to-skin contact.

You may be at increased risk of an STI if you have (or have had):

  • several different sexual partners;
  • sex with someone who has had many sexual partners; or
  • sexual contact without a condom or dental dam.

In Australia, young people (teenagers and adults under 29 years) tend to have a higher risk of getting an STI than older people. In addition, men who have sex with men have a higher risk of gonorrhoea and syphilis compared with heterosexuals.

You are also at high risk for some of these diseases — notably HIV/AIDS and hepatitis B — if you share needles when injecting intravenous drugs, or if you undergo body-piercing or tattooing and the instruments used are non-sterile and contaminated.

Can mothers pass STIs to their babies?

Having an STI while you are pregnant can affect the pregnancy and the health of your baby. For this reason, tests are routinely recommended in the early stages of pregnancy to check for certain STIs – which tests you should have will depend on your age and risk factors. Additional testing may be recommended for some women closer to the due date.

If you know that you have an STI during pregnancy, you can work with your doctor to reduce the risk of your baby being infected – treatment with antibiotics or antiviral medicines can often prevent infection. Caesarean delivery may be recommended for women with active genital herpes at the time of delivery.

Why it’s important to identify STIs early

Some common STIs can cause long-term complications affecting fertility and general health. Detecting sexually transmitted infections in their early stages and starting treatment straight away reduces the risk of complications such as pelvic inflammatory disease, infertility and chronic (ongoing) pelvic pain.

Early detection and treatment also means that spread of the infection to others can be prevented.

Different types of STIs

Sexually transmitted infections can be caused by bacteria, viruses or parasites.

Bacterial STIs include:

  • chlamydia;
  • gonorrhoea; and
  • syphilis.

Viral STIs include:

  • genital herpes;
  • genital warts (sometimes called anogenital warts);
  • hepatitis B; and

Other STIs include:

  • trichomoniasis — caused by a single-cell parasite.
  • non-gonococcal urethritis – urethritis with a cause other than gonorrhoea, may be bacterial or viral.


In women, chlamydia can cause symptoms including a white vaginal discharge, a burning sensation when urinating, painful intercourse, or vaginal bleeding that happens after sex or is not related to menstruation. Men with chlamydia can develop a clear, watery discharge from the penis, stinging or burning when urinating and pain in the testicles. But often, chlamydia causes no symptoms, especially in women.

Chlamydia infection can spread from the cervix to the uterus (womb) and fallopian tubes (which connect the ovaries to the uterus) in women, resulting in pelvic inflammatory disease. Pelvic inflammatory disease can damage the fallopian tubes, leading to abdominal pain, fertility problems or ectopic pregnancy (when the embryo lodges and grows in one of the fallopian tubes rather than in the uterus).

In men, chlamydia can spread from the penis to the prostate and the tubes that store and carry sperm — this can lead to fertility problems or long-term pain.


Rates of gonorrhoea infection have increased in Australia in recent years. In women, gonorrhoea can cause a cloudy vaginal discharge, pain during sex, abnormal vaginal bleeding, rectal discharge or irritation or painful bowel movements. Often, however, symptoms are absent in women.

In men, gonorrhoea can cause a yellowish, white or green discharge from the penis, burning pain while urinating, rectal discharge or irritation or painful bowel movements. However, gonorrhoea may not cause any symptoms at all.

Untreated, gonorrhoea can cause pelvic inflammatory disease in women and painful or swollen testicles (epididymo-orchitis) in men, which can lead to infertility in both men and women, and ectopic pregnancy in women.

Genital herpes

Genital herpes causes sores (blisters or ulcers) on or around the genitals and anus that come and go. There may be itching and burning in the genital area and discomfort when urinating. However, many people with genital herpes do not notice symptoms at all.

Genital warts

People with genital warts may notice tiny, soft, cauliflower-like growths appearing either singly or in clusters in and around the vagina, anus, penis, and/or scrotal area. However, it is much more common to be infected with a genital wart virus (also called human papillomavirus or HPV) yet have no symptoms.

There is a close relationship between some types of genital warts and cervical cancer. The majority of women with a genital wart virus will not develop cervical cancer. Nevertheless, you should have regular cervical cancer screening tests to make sure your cervix is healthy. Also, talk to your doctor about being vaccinated against the wart viruses most closely linked with cervical cancer (if you haven’t already had the vaccine).


Trichomoniasis is caused by a single-cell parasite that is transmitted sexually. In women, trichomoniasis can cause vaginal itching and pain with a foamy, greenish or yellow foul-smelling discharge, but there may be no symptoms.

Men with trichomoniasis may have a clear discharge from the penis, irritation of the urethra or a burning sensation after urinating or ejaculating, but most men with trichomoniasis do not have any symptoms. Trichomoniasis can lead to inflammation of the prostate (prostatitis).


Syphilis is another infection that seems to be on the rise. Syphilis usually first causes a painless sore on the genitals or anus, but sores are also possible in the mouth or inside the vagina or rectum, where they are not easily seen. There may also be swollen lymph nodes (lymph glands). This stage is called primary syphilis.

Many people with a syphilis sore are unaware of it, increasing the risk of them unwittingly passing the infection on. (Syphilis is spread through direct contact with a sore.) Although the sore will heal by itself, without treatment the person may develop secondary syphilis up to 2 months later.

Secondary syphilis can cause weight loss, fever, rash, enlarged lymph nodes, patchy hair loss, headaches and tiredness. The eyes and nervous system can also be involved.

The final stage of syphilis, tertiary syphilis, can occur months or years after symptoms of secondary syphilis disappear. In this stage there can be heart disease and problems with the nervous system. Tertiary syphilis can be fatal.

Hepatitis B

Hepatitis B is a viral infection that causes inflammation of the liver. Hepatitis can spread from person to person in a number of ways, including through sexual contact. Symptoms may include fever, jaundice, tiredness, nausea and abdominal pain or discomfort. Many people have no symptoms and don’t realise they have been infected.

Hepatitis B vaccination is recommended as part of the National Immunisation Program Schedule in Australia. Most adults who become infected with hepatitis B recover within about 6 months.

HIV (human immunodeficiency virus) infection

Soon after infection with HIV, the person may develop a flu-like illness with symptoms that can include headache, tiredness, fever, night sweats, sore throat, swollen lymph glands, diarrhoea and rash. Doctors call this a ‘seroconversion illness’, and it usually happens about 2 weeks after HIV infection. Most people recover from the seroconversion illness within a few weeks and will be seemingly well for a varying length of time.

These days, HIV can be managed with antiretroviral medicines. Without treatment with antiretroviral therapy, HIV infection can progressively damage the immune system, and symptoms of AIDS (acquired immunodeficiency syndrome) develop after an average of 8 to 10 years.

In recent years, HIV cases have decreased among non-Indigenous people, but among Aboriginal and Torres Strait Islander people they have increased.

Non-gonococcal urethritis (NGU)

Non-gonococcal urethritis is a term used to describe infection of the urethra (the tube that carries urine from the bladder to the outside) caused by microorganisms other than gonorrhoea, such as Mycoplasma genitalium, herpes simplex virus (HSV) and adenovirus. When no cause is found, it may be called non-specific urethritis (NSU). NGU can cause symptoms in men such as burning and stinging when they urinate, irritation or pain at the tip of the penis, or a white discharge from the penis.

Sexual health checks (STI check-ups)

If you are sexually active, it’s often a good idea to discuss testing for STIs with your doctor. You can go to your GP, local sexual health clinic or family planning clinic for a sexual health check, or STI check-up. Check-ups help identify infections early, and reduce your risk of developing complications and passing infections on to other people.

Your risk of STIs is increased by factors such as your sexual practices, age, and where you live. Which tests you should have and how often you should have them depends on your risk. Some people who are at high risk are advised to have regular testing every 12 months. You can also ask to be tested after having unprotected sex, even if you have no symptoms. Or you may want to be tested to get the all-clear for STIs at the start of a new relationship.

Recommended tests may include:

  • Urine tests for chlamydia and gonorrhoea.
  • Swab testing (taking a sample from your genitals or anus) for chlamydia, gonorrhoea and trichomoniasis. A swab test can be done by your doctor, or sometimes you can collect the swab sample yourself, which may be preferred by some people.
  • Blood tests for hepatitis B, HIV and syphilis.

There is no reliable screening test for genital herpes.

How quickly will I get my test results?

The results from an STI check-up are usually available within a few days. In some circumstances, your doctor may recommend repeat testing after 2, 4 or 12 weeks, because it can take that long from the time of exposure to be able to detect some infections.

A rapid HIV test (point of care test) is available in clinics that gives results within about 10-20 minutes. Testing can be done on blood or saliva. However, this test is not always reliable, so further testing will be needed to confirm the results.

Home testing kits (self-tests) can also be ordered online, although so far none of these have been included in the Australian Register of Therapeutic Goods (ARTG), meaning that their safety and performance have not have been confirmed by the Therapeutic Goods Administration (TGA).

Where to get help if you might have an STI

If you think you may have an STI, you can see your general practitioner (GP) or local sexual health clinic. Family Planning Clinics can also provide testing and treatment for STIs.

The doctor will ask about your symptoms and perform a physical examination. They may recommend tests for STIs. In some cases, treatment may be started immediately. Specific treatment can be prescribed once the test results come back.

What are the treatments for STIs?

Treatment for STIs depends on the type of infection. Uncomplicated infections with chlamydia, gonorrhoea, trichomoniasis and syphilis can be treated and cured with antibiotics. While some infections, including genital herpes and HIV cannot be cured, the symptoms can usually be treated and controlled with medicines.

In some cases, your doctor may recommend preventive treatment for certain STIs, just in case. This is called post-exposure prophylaxis (PEP), and can stop you developing these STIs, even if you have been exposed to them. If you’ve had unprotected sex, your doctor or the clinic can discuss with you the likelihood of your having been exposed to an STI versus the risk of side effects from the treatment.

Do I have to tell my partners about my STI?

Letting any recent and current sexual partners know that they may have been exposed to an STI is important. This is called contact tracing. Your doctor will talk to you about letting any partners know that they should be tested and treated. Contact tracing is recommended for most STIs, but it is generally not necessary to tell partners about genital warts or herpes.

You may choose to inform your partners yourself or your doctor (or another healthcare professional from a sexual health clinic) can approach them for you. This can be done anonymously, so that they are not aware that you are involved.

Alternatively, there are online partner notification services that can anonymously tell them that they may be at risk for an STI and should be tested and treated. This is done via email or SMS mobile phone messaging.

How to protect yourself from STIs

Using condoms can help reduce your risk of STIs as well as protect against unwanted pregnancies. This is sometimes referred to as ‘safe sex’. To be effective, condoms must be used properly and consistently – that is, every time you have sex. You should bear in mind that you can still get some STIs from skin-to-skin contact while using condoms.

Using a dental dam during oral sex is also recommended. A dental dam is a thin latex sheet that you place over the entrance to the vagina or anus during oral sex to avoid direct mouth to vagina or mouth to anus contact.They are available from chemists.

There are also vaccines available that can stop you getting some STIs, including hepatitis B vaccine and HPV vaccine. These vaccines are given routinely in childhood and adolescence, and are available free of charge as part of the National Immunisation Program Schedule. In some circumstances, it’s possible to be vaccinated after having sex to help prevent an infection developing if you are not already immunised.

If you are at high risk of catching HIV (for example, if your partner has HIV) you can take medicine to help prevent infection. This is called pre-exposure prophylaxis, and involves taking the anti-HIV medicine Truvada (tenofovir plus emtricitabine) once a day, in combination with safe sex practices. This medicine is not currently listed on the PBS and is expensive to buy in Australia, but you may be able to access the medicine for free through a clinical trial. Talk to your doctor or sexual health clinic about this medicine.

Testing and treatment for STIs after sexual assault

Your doctor, local sexual health clinic or local sexual assault service can help you following a sexual assault by giving support and counselling as well as medical advice. While your risk of catching an STI from a sexual assault is actually quite low, it is still important to be tested.

Your doctor will talk to you about your likely risk of infection, as well as the testing process and when to expect results. The type of test used to detect STIs varies depending on which infection is being tested for, and repeat tests are often needed after several weeks.

Post-exposure prophylaxis may be recommended following sexual assault. This is treatment aimed at preventing you from developing an STI after the event. Treatment may be recommended for Hepatitis B or HIV, and depending on the circumstances of the assault and the likelihood of infection, your doctor may also offer you antibiotics to prevent chlamydia, gonorrhoea or syphilis. Although many people are particularly concerned about contracting HIV, the risk of developing HIV after a sexual assault in Australia is very low.

Author: myDr


1. Australasian Sexual Health Alliance (ASHA). Australian STI management guidelines (updated Apr 2016). (accessed Nov 2017).
2. Genital and sexually transmitted infections (published November 2014). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2017 Jul. (accessed Nov 2017).
3. Royal Australian College of General Practitioners (RACGP). Guidelines for preventive activities in general practices, 9th Edition. 6.2 Sexually transmissible infections. (accessed Nov 2017).
4. Royal Children’s Hospital Melbourne. Sexually transmitted infections (STIs). (accessed Nov 2017).
5. Post-sexual assault antimicrobial prophylaxis (published November 2014. Amended July 2016). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2017 Jul. (accessed Oct 2017).
6. Royal Australian College of General Practitioners (RACGP). Clinical guidelines - Chapter 9. Sexual assault. (accessed Oct 2017).


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