Your body

Sexually transmissible infections

Sexually transmissible infections (STIs) like chlamydia, gonorrhoea, herpes or syphilis can affect any woman but they can have a more significant effect on women with HIV. HIV can cause more severe symptoms and can make an STI more difficult to treat. STIs can also place an additional burden on your immune system.

Using condoms for sex is a practical preventative measure although it won’t completely remove all risk of infection with some STIs. Many STIs do not have obvious symptoms so a regular check-up is recommended. Basically, the more sex you have with different people, the more regularly you should be tested for STIs. Many STIs can be quickly and easily dealt with if they are picked up early.


Herpes infections are caused by the herpes simplex virus, which can also cause cold sores on the mouth.

Symptoms are not always immediate but may include:

  • Blisters or a small split or graze in the skin
  • Itching and tingling
  • Burning/pain when urinating
  • Feeling generally unwell (muscular aches, headaches and fever)

Transmission occurs most easily when there are sores or blisters present but herpes can also be passed on when there are no obvious symptoms. Herpes is transmitted both sexually and non-sexually during skin-to-skin contact.

Herpes and HIV The frequency and severity of outbreaks of genital herpes may increase if your immune system is weakened by HIV. It is also possible for undiagnosed herpes infection (which has not caused symptoms in the past) to be ‘reactivated’ and cause symptomatic illness.

Herpes may increase the replication of HIV and therefore raise viral load particularly in untreated HIV. Symptomatic herpes in an HIV-negative person increases their risk of HIV infection.

Treatment Medical educators urge the aggressive treatment of herpes infections in people with HIV. Recurrent outbreaks may be treated with the antiviral drugs acyclovir (Zovirax), famiciclovir (Famvir) or valaciclovir (Valtrex). Reducing stress, having a healthy diet and taking care of yourself can all help reduce the recurrence of herpes.

Prevention Male or female condoms for vaginal or anal sex, and the use of barrier protection like dams, can help prevent infection but herpes can still be transmitted if condoms do not completely cover the infected area. Antiviral treatment may help prevent spread to sexual partners. Talk to your doctor.


Chlamydia is one of the most common STIs in Australia. It is caused by a bacterium and, if left untreated, can cause pelvic inflammatory disease (PID).

Symptoms Most people don’t have any symptoms, so don’t know they have chlamydia, which is why it is transmitted so frequently. When there are symptoms, they may include:

  • a change in vaginal discharge
  • irregular bleeding (especially after sex)
  • pelvic pain, including during sex
  • stinging or burning when passing urine

Transmission Chlamydia is spread through vaginal or anal sex without a condom. It can also be spread through oral sex.

Chlamydia and HIV Chlamydia greatly increases the viral load in semen, which makes it is easier to pass HIV on to other people.

Treatment Testing for chlamydia is easy — done by your doctor checking a urine sample. Chlamydia responds effectively and quickly to a short course of antibiotics. All sexual partners from the last six months should be tested and if they test positive, should be treated. It is important that you return to your doctor for a check-up once the treatment is completed to make sure you have no recurring infection. You should not have penetrative sex until you have received a negative test result following the check-up. If chlamydia is left untreated, it can cause serious health problems.

Prevention Chlamydia is prevented by using barrier protection like male or female condoms or dams every time you have sex. A chlamydia test is recommended whenever you change sexual partners and at least once a year if you are under 25 and sexually active.


Syphilis is caused by a bacterium. In Australia it is more common among gay men or in remote Aboriginal communities. There may be no symptoms for many years but syphilis can eventually cause serious health problems.

Symptoms Not all people with syphilis have symptoms so you may not know you have it unless you have a blood test for it. There are three stages of infection: primary, secondary and late syphilis. During the primary stage, a person may or may not notice a single or multiple sores that are usually firm, round and painless. These typically last 3 to 6 weeks. During the second stage, a person may notice a (usually non-itchy) rash on one or more areas of the body. Rashes may appear on the palms of the hands and the bottoms of the feet, however they can appear elsewhere. Symptoms may also include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. During the late stage, people may experience no symptoms for years but may then develop severe symptoms including damage to the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. Symptoms of late stage syphilis include difficulty coordinating muscle movements, paralysis, numbness, gradual blindness, and dementia. This damage may be serious enough to cause death.

Given how easy it can be to miss the symptoms of syphilis and the significant consequences of infection, testing for syphilis is important if you have any concerns. The diagnostic tests for syphilis may fail more frequently (producing false positives and negatives) in people with depleted immune systems. However, these failures are still believed to occur only rarely.

Transmission Syphilis is spread through unprotected vaginal, anal or oral sex. It can also be spread during pregnancy from an infected woman to the developing foetus.

Syphilis and HIV Genital sores caused by syphilis make it easier to transmit and acquire HIV. Syphilis can also progress to severe symptoms more quickly in people with HIV. There can be rapid progression from early syphilis to nervous system involvement in a matter of months, rather than the years or decades it takes in HIV-negative people. Complications to the nervous system may also occur in the early stage of infection, not just in the later stages.

Co-infection with HIV and syphilis may also result in more rapid onset of HIV disease and AIDS. It can decrease CD4 count (thereby damaging the immune system) and increase HIV viral load.

Syphilis can be more difficult to treat in people with HIV. There have also been cases of treatment failure in patients with secondary syphilis, all of whom were HIV positive. People with HIV can also progress to neurosyphilis despite standard treatment. If you have syphilis (early or latent), careful monitoring is advised so that any abnormality is treated immediately.

Treatment If treated early and appropriately, syphilis can easily be cured by penicillin injections or tablets. If you are allergic to penicillin there are alternative treatments. The duration and intensity of treatment depends on the stage of infection. Although the treatment is straightforward, it is important to have repeat blood tests to check that the treatment has worked. After treatment with penicillin some people (particularly those who have early syphilis) have a flu-like illness for 24 hours. This includes fevers, aches and pains and generally feeling unwell. It will go away and doesn’t require any specific treatment except plenty of rest and fluids.

Prevention Always use male or female condoms for vaginal, anal and oral sex. Condoms are not 100 per cent effective because they will only stop infection from the skin covered by the condom – they may not cover all sores or rashes in the affected area. Use dams for oral sex. Avoid contact with any sores. Avoid sex if either partner has infectious syphilis. You should not have sex until your rash or sore clears up. Regular testing is important as it is the only way to truly diagnose syphilis. Once tested, you and/or your partner can be treated. Wait at least a week after treatment before having sex.


Gonorrhoea is an infection caused by the bacteria Neisseria gonorrhoeae.

Symptoms Infection with gonorrhoea may have no symptoms. If symptoms do occur they may include:

  • an unusual discharge from the vagina
  • pain when urinating
  • deep abdominal pain during vaginal sex
  • sore, dry throat

Men may experience a discharge (pus) from the penis and/or a burning sensation when urinating.

Gonorrhoea can also infect the anus and the throat, usually without any symptoms at all.

Transmission Gonorrhoea is spread through unprotected vaginal, anal and oral sex.

Gonorrhoea and HIV HIV infection may exacerbate some of the symptoms and complications of gonorrhoea. Also, some research has shown a link between gonorrhoea and faster HIV disease progression. Cases of severe arthritis related to gonorrhoea have been reported in people with HIV. There are also reports of keratoconjunctivitis, a severe inflammation of the membrane which covers the eye.

Treatment Women are tested using a urine test or a swab from the cervix, anus or throat. Gonorrhoea is treated with antibiotics. A follow-up swab is taken to make sure the infection is gone. Men are tested by urine test or swab from the penis or a swab from the anus or throat.

Prevention Always use male or female condoms for vaginal, anal and oral sex. Use dams for oral sex to cover the vagina or anus. Make sure your current partners have been tested. You should not have any sexual contact for one week after completion of treatment (not even sex with a condom).