What is a Sexually Transmitted infection (STI)?

STIs are passed on by unprotected vaginal, anal and oral sex, and by genital skin to skin contact. Some STIs caused by bacteria can be treated while others caused by a virus may remain in the body, with treatment aimed at reducing the symptoms.

How can I avoid an STI?

The World Health Organisation has stated that the best way to avoid becoming infected with an STI is to stay faithful to an uninfected partner for life.

What else?

Delaying becoming sexually active is a positive health choice.

Having fewer sexual partners reduces the risk of infection, although you can get an STI from one infected partner.

Using a condom correctly every time means that you are less likely to get an STI but it is not 100% safe.

You have a choice about your sexual health whether you’ve had sex or not. It affects your whole person, not just your body. Take care of yourself.

What you need to know about...


Caused by a bacteria. The highest rate of infection is amongst teenagers.

Symptoms: 70-80% of infected men and women have no obvious symptoms

Men: Pain passing urine, discharge from penis, painful testicles.

Women: pain and/or bleeding during or after sex. Pain passing urine. Pelvic pain, and vaginal discharge.

Effects on Health:

Men: possible reduced fertility, and testicular infection

Women: can lead to pain and pelvic inflammation, ectopic pregnancy, and infertility.

Treatment: A course of antibiotics is 95% effective.

Genital Herpes

Caused by a virus

Symptoms: Men and Women: small blisters or sores in the genital area, pain passing urine, and flulike symptoms with the first episode.

Effects on Health: a pregnant woman might infect her baby.

Treatment: No cure. Anti-viral drugs can reduce severity and frequency of attacks.

Genital Warts

Caused by the Human Papilloma Virus (HPV), the most common viral STI.


Men and Women: small lumps or warts on the genitals that cause irritation. Most people are unaware they are infected.

Effects on Health:

Women: a few strains of HPV are linked with cervical cancer.

Treatment: No permanent cure so the virus may stay in the body. Visible warts can be removed by a liquid chemical, freezing, heat or laser treatment


Caused by a bacteria


Men: 10% get no symptoms. Pain passing urine, discharge from penis, and pain in the testicles Women: 50% have no symptoms but may include vaginal discharge, pain passing urine and pelvic pain

Effects on Health:

Women: can lead to pelvic inflammation, ectopic pregnancy and infertility.

Men: testicular or prostate inflammation, infertility.

Treatment: A course of antibiotics

Human Immuno-Deficiency Virus (HIV)

Nearly half new infections are through heterosexual transmission.

Symptoms: early symptoms are flu-like, followed by mild muscle ache, low-grade fever, rash and swelling of the lymph glands.

Effects on Health: Without drugs, almost all HIV infected people will develop AIDS and die.

Treatment: No cure. Anti-retroviral drugs can reduce the multiplication of the virus delaying the onset of AIDS and helping infected people to live longer.


Hepatitis B and C are viruses that affect the liver and are passed on by unprotected sex and contaminated needles.


Men and women: flu-like illness, nausea, vomiting and diarrhoea, weight loss, jaundice, and itchy skin.

Effects on Health:

Men and Women: most people with Hepatitis B will clear the virus, but 2-10% can become carriers that may lead to liver damage and cancer. Only 20% of those infected with Hepatitis C clear the virus 80% remain infected and can get liver damage or cancer.

Treatment: Hepatitis B vaccines are effective. There is no vaccine for Hepatitis C.


Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.

Syphilis is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying.

Many people infected with syphilis do not have any symptoms for years, yet remain at risk for late complications if they are not treated. Although transmission occurs from persons with sores who are in the primary or secondary stage, many of these sores are unrecognized. Thus, transmission may occur from persons who are unaware of their infection.

The syphilis bacterium can infect the baby of a woman during her pregnancy. Depending on how long a pregnant woman has been infected, she may have a high risk of having a stillbirth (a baby born dead) or of giving birth to a baby who dies shortly after birth. An infected baby may be born without signs or symptoms of disease. However, if not treated immediately, the baby may develop serious problems within a few weeks. Untreated babies may become developmentally delayed, have seizures, or die.

Many STIs have no symptoms.

If you

  • have had unprotected sex or condom failure even once
  • or had genital skin contact with someone who may be infected
  • or had previous partners who might have been infected
  • or if you don’t know the sexual history of previous partners

then it is possible for you to have an STI.

Some people carry not just one but a number of STIs.

If you think you may have an STI, even if you have no symptoms, you should have a check up.