Sexually transmissible infections (STIs) are infections that are passed on from person to person usually through body fluids during sexual contact. Sexual contact can include vaginal sex, anal sex, oral sex (mouth-penis/vagina/anus contact), and use of sex toys (such as vibrators).
Another name for STIs is venereal disease - a technical word that also means a disease spread through sexual contact. Other words used for STIs include sexually transmitted infections and sexually transmitted diseases.
In the medical profession, the preferred word is sexually transmissible infections because most infections are short-lived if they are detected early and properly treated. Another reason for using the word infection is because a person can have an infection, pass it on, and not actually show any symptoms of disease.
More than 20 different STIs have been identified. Some of the more common STIs include: chlamydia, genital herpes, genital warts, gonorrhoea, human immunodeficiency virus (HIV), pubic lice ('crabs'), syphilis, and viral hepatitis A, B, and C.
Each STI belongs to one of four major infection-type groups. These groups are labelled according to the name given to the organism (an individual form of life, such as plant or animal) that causes the infection:
parasite - for example, trichomoniasis and pubic lice
STIs are caused by microorganisms - a name given to very small organisms which belong to certain groups, such as bacteria, virus, and fungi. The microorganisms are passed on from one person to another through semen, fluid from the vagina, blood, or saliva, all of which generally occur during sexual activity.
STIs can also be passed on through skin-to-skin contact because some types of microorganisms live on the skin - this is how genital herpes and genital warts are passed on.
The most common way you can contract (catch) an STI is by having sexual contact with an infected person. It is very unlikely for you to get an STI from a non-living object (such as a toilet seat) unless the object has fresh and wet infected body fluid on it.
Less common ways of contracting STIs:
It is possible to have more than one STI at a time. For example, it is common for people who have gonorrhoea to also have chlamydia.
The symptoms of an STI can vary depending on the type of STI people have. Some common symptoms include:
It is important to remember that many people who have an STI do not show any symptoms of the infection, so they often do not know they are infected. This is a problem for two reasons:
the infection can cause serious health problems if left untreated
Examples of some of the health problems STIs can cause if left untreated:
urethritis (swelling of the urethra, the tube leading from the bladder to outside the body)
The only way you can be certain if you have an STI is by making an appointment with your local doctor, family planning clinic, or sexual health clinic to have a sexual health check. During a sexual health check, the health worker will usually:
Some people are more at risk of contracting STIs. A sexual health check is highly recommended if you:
share needles/injecting equipment
Most STIs can be effectively treated if detected early. Some STIs, such as viral STIs, cannot be cured but the symptoms can be managed with medication.
The treatment of STIs involves three steps:
To avoid the spread of STIs, it is important that you avoid having sex until after the follow-up appointment.
The medications used to treat STIs will vary depending on the type of STI:
parasites - antibiotics, topical medication, or medicated shampoo
The only way you can truly avoid contracting STIs is through abstinence (stop having sex).
Other ways you can reduce your risk of getting STIs include: