Control of sexually transmitted infections

A sexually transmitted infection (STI) is an infection passed from one person to another through sexual contact. Its spread can be reduced by limiting contact with infection and by identifying and treating infected people.

Reducing transmission during sexual contact

Condoms reduce the risk of transmission by limiting contact with infectious body fluids. Avoiding sexual contact when an infection is known or suspected also reduces the chance of passing it to another person. Reducing the number of sexual partners reduces the opportunities for an STI to spread between people.

Testing, treatment and informing partners

A person can have an STI without obvious symptoms, so they may not know they have an infection. Testing can identify an infection even when there are no obvious symptoms.

Treatment helps control an infection and prevent further transmission. Informing sexual partners allows them to seek testing and treatment if needed, reducing the chance that they will unknowingly pass the infection on.

HIV transmission

Human immunodeficiency virus (HIV) is a pathogen that can pass from one person to another through certain body fluids. These include blood, semen, vaginal fluid and breast milk.

HIV can be transmitted during sexual contact when an infected fluid enters another person’s body. The risk is higher when a condom is not used; condoms reduce the risk of transmission.

HIV can also pass through blood-to-blood contact. For example, sharing a needle contaminated with infected blood can transfer the virus to another person.

A mother with HIV can pass the virus to her child during pregnancy, birth or breastfeeding. Sexual contact is therefore one route of transmission, but it is not the only one.

HIV infection and AIDS

HIV is a virus that damages cells involved in the body’s defence against disease. Over time, this damage can weaken the immune system, making it harder for the body to fight infections.

If the immune system becomes severely damaged, HIV infection may progress to acquired immunodeficiency syndrome (AIDS). A person with AIDS is especially vulnerable to other infections because their immune defences are severely weakened.

HIV and AIDS are not the same thing. HIV is the pathogen; AIDS is a possible later condition caused by the effects of HIV on the immune system. Not everyone with HIV develops AIDS.