Please note that information in this section is intended as educational information only, and is geared towards sexually active individuals with a vagina. Please see the resources section for links to additional information, and sources of medical advice.

A sexually transmitted infection (STI) is an infection caused by an organism (bacteria, virus or parasite) that can be passed between individuals during sexual contact. STIs are sometimes also called STDs (sexually transmitted diseases).

Different types of infections can be passed through various contact types such as:

Oral Sex

Vaginal Sex

Anal Sex

Sharing Toys

Skin to Skin Contact

Some infections are easier to acquire than others, and can infect different areas. Different infections can also have different symptoms.

Getting screened for STIs is important for all sexually active people, so that any infections can be treated or managed as soon as possible.

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There are multiple ways that STIs can be transmitted:

Sexual Transmission
  • • Genital to genital
  • • Genital to anal
  • • Oral to genital/anal
Skin to Skin Contact
  • • Kissing
  • • Non-penetrative sex
  • • Body rubbing
Body Fluid Exchange
  • • Semen
  • • Blood
  • • Vaginal fluid
Sharing Items
  • • Sex toys
  • • Needles or other drug tools
  • • Shared clothing
  • • Shared bedding
  • • Genital touching
Mother to child
  • • Pregnancy
  • • Delivery
  • • Breastmilk

Different STIs can be transmitted in different ways. They are most frequently transmitted through fluids during unprotected sex. STIs often have no symptoms, or symptoms take time to appear. So infections can be spread without even realizing that they are being spread.

STIs cannot be spread through social contact like hugging (with clothes on) and shaking hands.

Chlamydia, Gonorrhea, Syphilis, Trichomoniasis, HIV, Hepatitis, HPV
Genital warts (low risk HPV), Herpes, Scabies, Pubic lice
Chlamydia, Gonorrhea, HIV, Herpes, Hepatitis
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In many cases, STI infections can be asymptomatic – which means you don’t experience any symptoms, even if you have an infection. If someone else is asymptomatic, you also can’t tell if they have an STI. The only way to be sure, is to get tested.

It can take weeks or even months before symptoms appear. During that time, it’s possible to pass on an infection to someone else.

Sores or Warts

Abdominal Pain

Vaginal Discharge

Genital Itching

Pain During Sex or Urinating

Unusual Bleeding

Groin Pain or Swelling


In the case of HIV and Hepatitis C, early symptoms might look similar to flu symptoms. Infections with high risk strains of HPV usually do not have any symptoms at all.

Some infections can take weeks or even months before symptoms occur. But during that period, the infections can be passed on to other people.

Getting screened is important, even if you don’t have any symptoms.

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In some cases, your immune system may clear an infection on its own.

But in other cases, infections can progress to serious diseases that can have negative effects on your health. Some potential consequences of untreated STI infections include:

Pregnancy Complications


Chronic Pelvic Pain

Pelvic Inflammatory Disease

Reproductive System Cancers

Increased Risk of HIV

The amount of time it takes for an infection to develop into more serious issue can vary quite a bit. Some STIs are curable, but others are not (they may not go away entirely). But most STIs can be either treated or managed.

It's important to get screened regularly if you are sexually active, or have not been tested since you were last sexually active. This is so you and your healthcare provider can start on a treatment or management plan and prevent diseases from occurring.

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The risk of STIs are a part of being a sexually active individual. There are certain things that can increase the risk of getting or spreading STIs. The most risky is having unprotected sex.

Not Using Protection

Have multiple partners

Have an existing STI

Paying for Sex or Sex Work

You can be pro-active about preventing STIs, or detecting them early using these strategies:

Using Protection During Sex
  • • Use condoms or female condoms for penetrative sex with any body parts or objects
  • • Use dental dams and condoms for oral sex
  • • Remember that some contraceptive strategies (birth control pill, diaphragm, IUDs) prevent pregnancy, but not STIs

Get Screened Appropriately
  • • If you had unprotected sex, or the protection failed / broke
  • • If you have or are planning to have a new sexual partner
  • • You or your partner is having sex with another sexual partner
  • • Your partner or a previous partner has or had an STI

Learn & Talk About It
  • • Learn about STIs (which you are doing - good job!)
  • • Talk to your partner about prevention and screening
  • • Talk to your doctor about any concerns or symptoms
  • • Talk to your partner(s) if you have an STI, so they can check

There are also vaccines available for Hepatitis A/B (not Hepatitis C) and HPV, that will help protect you. But remember that even if you are vaccinated, you should still practice safe sex and regular screening.

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Notification & Reporting

Partner notification is the act of notifying previous sexual partners about a recently discovered STI, or informing future sexual partners about a non-curable STI.

This may be an uncomfortable or difficult conversation, but is very important to the health of your partner(s) and any their partner(s), and to stopping the spread of STIs.

A few STIs are considered higher public health risks, and are called “reportable” infections. This means that in addition to partner notification, public health agencies will also keep track of the number of infections and may contact each person who tests positive.

Reportable infections in Canada are:







With reportable infections, a public health worker may be able to notify previous partners anonymously for you. You should contact your local sexual health unit to learn more about this.

Find information on your local sexual health unit in the Resources section.

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