19.1

Sexually transmitted infections (STIs) are infections spread from one person to another during sexual activity or actions that involve contact with a person's reproductive organs.
STIs can affect people of all sexes, ages, races, nationalities, and ethnic origins.
STIs are caused by disease-causing microorganisms, including bacteria, viruses, and protozoa.

Engaging in sexual activity with one partner who has an STI is all it takes to contract an STI.
People with more sexual partners have a greater chance of getting an STI.
Although it is possible for certain oral STIs to spread through kissing, most STIs spread only through sexual activity.

STIs can cause serious damage to the body, including inflammation, damage to the reproductive organs, and infertility.
If left untreated, STIs can also damage the brain, heart, liver, and other internal organs.
Some STIs are incurable, and some can cause cancer or be fatal.

Nearly three million new cases of chlamydia are reported each year in the United States.
Chlamydia is sometimes called a "silent disease" because it causes few symptoms.
The majority of chlamydia infections occur in young people aged 15-24.
Chlamydia poses a threat to the health of the female reproductive system, especially for young people whose bodies have not fully developed.

Symptoms of chlamydia are often mild or absent.
Males may experience burning during urination, itching at the opening of the penis, and watery discharge from the penis.
Females may experience abnormal vaginal discharge and a burning sensation during urination.

PID is a condition that affects the fallopian tubes and pelvic cavity and can cause infertility.
Chlamydia can cause PID if left untreated.

Gonorrhea is a bacterial STI that primarily affects the rectum, throat, and reproductive system.
An estimated 820,000 people contract gonorrhea each year.
70% of cases are in young adults aged 15-24.

Males may experience burning during urination and yellow or white urethral discharge.
Females may experience mild burning or itching, pelvic pain, abnormal bleeding, and abnormal vaginal discharge.

Gonorrhea can cause Pelvic Inflammatory Disease (PID) and infertility if left untreated.
Can also cause anal itching and bleeding or a sore throat.

Healthcare provider may swab and examine urethral discharge from the penis.
Females: Urine test or laboratory analysis of a sample swabbed from an infected body part.
Antibiotics can cure gonorrhea, but some bacteria are antibiotic-resistant.

Syphilis is a bacterial STI that can be fatal if left untreated.
Number of syphilis infections has been increasing each year since 2001.
Syphilis infections among people aged 15-19 increased by about 10% between 2016 and 2017.

Primary syphilis: A sore called a chancre develops at the site of infection.
Secondary syphilis: A red or copper-colored rash appears.
Latent syphilis: The person experiences no noticeable signs or symptoms.
Late-stage syphilis: The infection damages the brain and can lead to dementia and paralysis.

Primary syphilis: A sore may not itch or be painful.
Secondary syphilis: A rash does not itch, may go unnoticed, and cannot transmit syphilis.
Latent syphilis: No noticeable signs or symptoms.

To diagnose syphilis, a doctor will examine a sample swabbed from a syphilis sore using a special microscope.
Doctors can also use blood tests to detect antibodies the body makes in response to syphilis.
Antibiotics can cure syphilis, but cannot reverse or repair the organ damage caused by late-stage syphilis.

Most males with trichomoniasis have no symptoms.
Females may experience yellow-green vaginal discharge with a foul odor and burning, itching, and pain during urination and sexual intercourse.

Trichomoniasis is difficult to diagnose without an examination and laboratory test.
To diagnose infections, a sample of vaginal discharge or urine is examined under a microscope or cultured.
People who have no symptoms can still pass trichomoniasis on to others.

Genital herpes is a viral infection that can affect almost any part of the body.
Genital herpes is caused by the herpes simplex virus (HSV).
HSV type 1 (HSV-1) causes cold sores on the mouth and lips, but it can also cause genital infections.
HSV type 2 (HSV-2) causes genital infections exclusively and spreads through sexual activity.

Sometimes, a physical examination and laboratory tests of samples swabbed from the open sores can diagnose herpes.
If a person has no visible sores, a blood test can detect antibodies that indicate the presence of the HSV.
No cure exists for herpes, but prescription medications can control the frequency and severity of outbreaks and lower the risk of transmission.

With 14 million new infections each year, human papillomavirus (HPV) is the most common STI in the US.
HPV infects cells in the skin and genital membranes, causing them to grow abnormally.

For females, a laboratory test can detect an HPV infection and identify the type of HPV.
If an HPV infection is present, a doctor will recommend regular follow-up appointments for females under age 30.
Doctors screen for cervical cancer using a Pap test, also called a Pap smear.
Receiving an HPV vaccine can reduce a person's risk of contracting HPV.### Preventing and Treating STIs
Learning outcomes of this lesson include:
- Explaining the importance of abstinence in preventing STIs
- Developing skills for a sexual health assessment
- Analyzing the effectiveness of different prevention methods
- Identifying the three critical components of good health
- Identifying resources for obtaining information about STIs
- Summarizing treatment options for different STIs

Practice health-enhancing strategies with a partner to reduce risks and enhance health
Consider discussing and revising strategies after reading this lesson