Topic Overview

Aside from colds and the flu, sexually transmitted infections (STIs) are some of the most widespread infections in the world. STIs affect both men and women, and almost half of all STIs occur in people younger than 25 years old. Exposure to an STI can occur any time you have sexual contact with anyone that involves the genitals, the mouth (oral), or the rectum (anal). Exposure is more likely if you have more than one sex partner or do not use condoms. Some STIs can be passed by nonsexual contact, such as by sharing needles or during the delivery of a baby or during breastfeeding. Sexually transmitted infections (STIs) are also called sexually transmitted diseases (STDs).

STIs are a worldwide public health concern because there is more opportunity for STIs to be spread as more people travel and engage in sexual activities. Some STIs have been linked to an increased risk of certain cancers and infection with human immunodeficiency virus (HIV). Pregnant women can spread STIs to their babies. Many people may not have symptoms of an STI but are still able to spread an infection. STI testing can help find problems early on so that treatment can begin if needed. It is important to practice safer sex with all partners, especially if you or they have high-risk sexual behaviours. See the Prevention section of this topic.

If you think you may have symptoms of an STI:

• Do not have sexual contact or activity while waiting for your appointment. This will prevent the spread of the infection.
• Women should not douche. Douching changes the normal balance of bacteria in the vagina. Douching may flush an infection up into your uterus or fallopian tubes and cause pelvic inflammatory disease (PID).

Common sexually transmitted infections

There are at least 20 different STIs. They can be caused by viruses, bacteria, and protozoa. Some of the most common STIs are:

• Chlamydia.
• Genital herpes.
• Genital warts or human papillomavirus (HPV). Certain high-risk types of HPV can cause cervical cancer in women.
• Gonorrhea.
• Hepatitis B.
• Syphilis.
• Trichomoniasis.
• Human immunodeficiency virus (HIV), which causes AIDS. Having other STIs, such as genital herpes, can increase your risk of HIV.
• Other infections that may be sexually transmitted. These include hepatitis A, cytomegalovirus, molluscum contagiosum, Mycoplasma genitalium, hepatitis C, and possibly bacterial vaginosis.
• Scabies and pubic lice, which can be spread by sexual contact.

Bacterial STIs can be treated and cured, but STIs caused by viruses usually cannot be cured. You can get a bacterial STI over and over again, even if it is one that you were treated for and cured of in the past.

Sexually active teens and young adults

Sexually active teenagers and young adults are at high risk for STIs because they have biological changes during the teen years that increase their risk for getting an STI and they may be more likely to:

• Have unprotected sex.
• Engage in high-risk sexual behaviours.
• Have partners who have high-risk sexual behaviours.

The 2010 Public Health Agency of Canada STI information shows that:

• Young women ages 15 to 24 and young men ages 20 to 29 are more likely to get STIs.
• Chlamydia is the most commonly diagnosed and reported STI in Canada. Young women ages 15 to 24 and young men ages 20 to 29 are most affected.
• Gonorrhea has increased by 94% over the past 10 years. Men account for two-thirds of reported cases. Young men ages 20 to 29 and young women ages 15 to 24 are most affected.
• About 70% of adults will have had genital types of HPV at least once in their lifetimes. Teen and young adult women and men are most affected.
• Genital herpes infection affects women more than men. This infection is common in teen and adult women and men.
• There was a 20% rise in HIV positive test reports between 2000 and 2004. It is more common in injection drug users, men who have sex with men, and young women ages 15 to 19.
• Syphilis rates have increased across Canada in the past 15 years. Men ages 30 to 39 who have sex with men and sex workers are most affected.
• Hepatitis B. Acute hepatitis B is twice as high for men than for women. It is highest in adults ages 30 to 39. Injection drug users, people with multiple sex partners, and people who have sexual or household contacts with an acute or chronic carrier are most affected.

It is important to seek treatment if you think you may have an STI or have been exposed to an STI. Most health departments, family planning clinics, and STI clinics provide confidential services for the diagnosis and treatment of STIs. Early treatment can cure a bacterial STI and prevent complications.

If you are a parent of a teenager, there are many resources available, such as your health professional or family planning clinics, to help you talk with your teen about safer sex, preventing STIs, and being evaluated and treated for STIs.

Risks specific to women with sexually transmitted infections

In women, STIs can cause a serious infection of the uterus and fallopian tubes (reproductive organs) called pelvic inflammatory disease (PID). PID may cause scar tissue that blocks the fallopian tubes, leading to infertility, ectopic pregnancy, pelvic abscess, or chronic pelvic pain.

STIs in pregnant women may cause problems such as:

• Miscarriage.
• Low birth weight.
• Premature delivery.
• Infections in their newborn baby, such as pneumonia, eye infections, or nervous system problems.

Risks specific to men with sexually transmitted infections

• Infection and inflammation of the epididymis, urethra, anus, and prostate

Any child or vulnerable adult with symptoms of an STI needs to be evaluated by a health professional to determine the cause and to assess for possible sexual abuse.