Hesperian Health Guides
Sexually Transmitted Infections
Sexually transmitted infections (STIs) are infections that pass from one person to another during sex.
Most types of sex can spread a STI. It can be penis to vagina sex, penis to anus sex, or oral sex (mouth to penis, mouth to vagina). Sometimes STIs can pass from just rubbing an infected penis or vagina against another person’s genitals.
Signs caused by STIs include pain during sex, unusual discharge from the vagina, penis, or anus, or bumps, sores, or blisters on the genitals.
It is very common to have a STI and have no signs at all. Even if there are no signs, the STIs can pass from one person to another. A lab test done in a clinic is the best way to find out if you have a STI and find the right treatment to cure it. Help any person you have had sex with to also get tested and treated. If both of you do not get treated, you will get infected again and infect other people. In places where testing for STIs is not available, it is still important to treat infections right away.
Most STIs are cured after treatment with antibiotics. Other STIs do not go away but can be managed with medicine. There are also treatments to reduce pain and help with discomfort while the medicine takes effect (see How To Feel Better While You Heal From a STI).
Not having sex or being certain your sex partner does not have a STI are the best ways to prevent STIs. Because this is not always possible, prevent infections from sex by using condoms every time as another way to make getting a STI less likely. Health workers can play an important role by treating people with STIs with respect and dignity.
Why STIs are a serious problem
Because sex is normal and common, STIs are also common. When STIs are not treated, they can harm adults and children. STIs can cause:
- infertility.
- babies born too early, too small, blind, sick, or dead.
- death from severe infection.
- lasting pain.
- cancer of the cervix or throat or anus.
- increased risk of getting other STIs, including HIV.
How STIs pass to partners through sex
Sex that involves the genitals touching and oral sex (using the mouth on the genitals), can both pass STIs. The person on the receiving end of sexual intercourse, getting penetrated in the vagina or anus, is more at risk. If no condom is used, semen which may carry infection stays inside the vagina, anus, or mouth. The action of penetration can rub and open the skin inside the vagina or anus, increasing the possibility that an infection enters the body. This happens even if the person doesn’t notice there are sores inside the vagina or anus. Sores or irritation on the outside part of the genitals can also pass STIs, including HIV, more easily.
What to do if you might have a STI
- Get tested if testing is available
- Get treated for the infection right away, do not wait to become more ill.
- Help your partner get treated at the same time. That way you will not get the infection again if you have sex together.