Chapter 16 Preventing Sexually Transmitted Infections
Understanding Infectious Diseases • Pathogen – A biological agent that causes disease or illness to its host; also known as an infectious agent.
• Infection – Results when a pathogen invades and begins growing within a host.
Understanding Infectious Diseases • Infectious disease – Results only if and when, as a consequence of the invasion and growth of a pathogen, tissue function is impaired; the consequence of impaired tissue function.
• Chain of infection – Describes how disease is transmitted from one living organism to another.
Chain of Infection • Pathogen – Infectivity – Pathogenicity – Virulence
• Reservoir – Humans – Animals – Vehicles
Portals of Entry and Exit
Chain of Infection • Transmission – Direct – Indirect
• A New Host – An uninfected person who can become infected
Chain of Infection and Disease Prevention
Body’s Defense Mechanisms
Body’s Defense Mechanisms
Sexually Transmitted Infections (STIs) • STIs – Spread primarily through person-to-person sexual contact. – Is a slightly more precise term than sexually transmitted disease (STD) because the infection comes first and is what needs to be prevented. – There are more than 25 different infectious bacteria, viruses, and parasites that are transmitted through sexual contact.
Common STIs
Estimated Yearly Number of STIs
Reasons for High STI Rates • STIs – Spread primarily through person-to-person sexual contact. – Is a slightly more precise term than sexually transmitted disease (STD) because the infection comes first and is what needs to be prevented. – There are more than 25 different infectious bacteria, viruses, and parasites that are transmitted through sexual contact.
Reasons for High STI Rates • Failure to inform • Multiple sexual partners • False sense of security • Absence of signs and symptoms • Untreated conditions
Reasons for High STI Rates • Impaired judgment • Lack of immunity • Value judgments • Denial; untreated conditions
Sexually Transmitted Viral Infections • HIV infection and AIDS • Genital herpes • Genital warts • Hepatitis B
HIV Infection and AIDS • Human immunodeficiency virus (HIV) – The virus that causes Acquired Immunodeficiency Syndrome (AIDS); it causes a defect in the body’s immune system by invading and then multiplying within the white blood cells. – An HIV-infected person is diagnosed with AIDS when his or her immune system is seriously compromised and manifestations of HIV infection are severe.
Methods of HIV Transmission • Blood • Semen (which contains small amounts of blood) • Vaginal fluids
Exposure Categories of Adults and Adolescents
Reproduced from Centers for Disease Control and Prevention. (2012). HIV/AIDS in the United States. Online: http://www.cdc.gov/hiv/resources/factsheets/us.htm.
Genital Herpes • The virus Herpes simplex, or HSV, causes herpes and can cause cold sores on the mouth, skin rashes, and lesions on the penis, vagina, or rectum. • As many as one out of four American adults have been infected with genital herpes. • Oral herpes is frequently caused by HSV-1 and genital herpes is most frequently caused by HSV2. – Both HSV-1 and HSV-2 can cause genital and oral infections.
Genital Herpes • The major symptoms of genital herpes are the presence of one or more blisters, which become painful sores; fever; and occasionally pain in the lower abdomen. • There is no cure for herpes. • Herpes is extremely contagious when there is a sore present.
Herpes
Courtesy of Dr. Hermann/CDC
Sexually Transmitted Warts • Sexually transmitted warts are hard, cauliflowerlike growths appearing on the penis in men, on the external genitals and cervix in women, and in the anal region in both sexes. • Warts are caused by several of the varieties of human papillomavirus (HPV). • Warts can be removed.
Genital Warts
Š Dr. P. Marazzi//Photo Researchers, Inc.
Hepatitis B • Disease of the liver, is a caused by the hepatitis B virus (HBV). • It is transmitted sexually and in blood. • While there is no cure for HBV, there is an HBV vaccine available.
Sexually Transmitted Bacterial Infections • Chlamydia • Gonorrhea • Syphilis
Chlamydia • Chlamydia infests certain cells lining the mucous membranes of the genitals, mouth, anus, rectum, the conjunctiva of the eyes, and occasionally the lungs. • It is caused by the bacterium Chlamydia trichomatis. • It is the most prevalent STD in the United States. • Infected individuals often have mild or no symptoms.
Gonorrhea • Also known as “the clap,” gonorrhea is caused by the bacterium Neisseria gonorrheae. • Its organisms infect the mucous membranes of the body, most often the genitals, reproductive organs, mouth and throat, anus, and eyes. • Transmission in adults almost always occurs by genital, oral, or anal sexual contact and infection of the eyes occurs by hand.
Gonorrhea • Similar to chlamydia, many people infected with gonorrheal organisms do not develop symptoms. • Men may develop epididymitis and women may develop infections of the uterus, fallopian tubes, and pelvic region if the infection progresses. • Gonorrhea untreated can cause sterility. • Gonorrhea can be treated with antibiotics.
Gonorrhea
Š Science VU/Visuals Unlimited
Syphilis • Caused by a bacterium called Treponema pallidum and transmitted through genital, oral, and anal contact, as well as from blood. • A painless open sore called a chancre is the first noticeable sign of syphilis.
Syphilis • Infection enters a latency period if left untreated. • In the tertiary stage, the disease damages vitals organs causing severe symptoms and may lead to death. • It can be treated at any stage with antibiotics.
Syphilitic Chancre of the Penis
Š Biophoto Associates/Photo Researchers, Inc.
Other Sexually Transmitted Infections • Trichomonas vaginalis • Pubic lice • Scabies
Other Sexually Transmitted Infections Trichomonas vaginalis • Is a one-celled organism that burrows under the vaginal mucosa to cause trichomonas, or trick. • Symptoms include a foul-smelling, foamywhite or yellow-green discharge that irritates the vagina.
Other Sexually Transmitted Infections Pubic lice • Also known as “crabs,” are barely visible insects that live on hair shafts primarily in the genital-rectal region and occasionally on hair in the armpits, beard, and eyelashes. Scabies • Is an infestation of certain regions of the skin by extremely small mites. • Can be transmitted sexually and nonsexually.
Preventing STIs • Abstaining from sexual activity – Most effective behavior for eliminating the risk of contracting a STI. • Long-term monogamous sexual relationship – Not fail safe because some seemingly trustworthy sexual partners have been known to have a sexual relationship with others.
Preventing STIs • Limiting the number of partners – Delaying having sex with them until you know them long enough to assess their risk as sexual partners. • Using latex condoms – Latex condoms can protect you during contact between the penis, mouth, vagina, or rectum.
How to Put on a Condom
Practicing Safer Sex • Safer sex – Is a general term used to describe methods for reducing the chance that you will contract or spread STIs.
Safer Sex
Barriers to Practicing Safer Sex • Denying that there is a risk. • Believing that the campus community is somehow insulated from STIs. • Feeling guilty and uncomfortable about being sexual. • Succumbing to social and peer pressure to be sexual.
Regular Medical Check-Ups • Any sexually active person should have regular medical check-ups, at least yearly, to check for the presence of infections and to diagnose and treat any signs and symptoms of STIs. • STIs can cause serious health problems if left untreated. • You should not feel afraid to discuss with your health-care provider your sexual practices or to request STI tests.