Sexually Transmitted Infections Chapter 16 Learning Objectives An

Sexually Transmitted Infections Chapter 16

Learning Objectives • • • An Epidemic Bacterial Infections Vaginal Infections Viral Infections Ectoparasitic Infestations

A Epidemic Sexually transmitted infections (STIs) Infections transmitted through sexual contact • 19 million new cases per year in US • 700, 000 cases of gonorrhea each year • 1 in 6 Americans infected with HSV-2 • 6 million new cases of HPV each year • 50% of college population infected • 50, 000 new HIV/AIDS each year in US

An Epidemic Why the surge? Increased number of young people having sex Failure to use condoms Some infections have no symptoms Multiple partners Drug use Lack of education

Critical Thinking The US has the highest rate of infection by STIs in the industrialized world. Explain why you think this is so.

Bacterial Infections Bacteria • One-celled microorganisms that have no chlorophyll and can give rise to many illnesses

Bacterial Infections Gonorrhea • “The clap” or “the drip” • Characterized by discharge and burning urination • If untreated can lead to PID and infertility Transmission • Unprotected vaginal, or anal sex or from mother to newborn during delivery • Thrives in warm, most environments • Highly contagious • 50% of women and 25% of men infected after single exposure

Gonorrhea – Symptoms and Treatment Men Women DX &Treatment • Penile discharge • Inflamed urethra, burning sensation when urinating • Fertility problems if not treated early • Symptoms occur 25 days after exposure • Inflammation of cervix resulting in discharge • 80% experience no symptoms • Untreated can result in PID and lead to infertility • Involves clinical inspection of the genitals by a physician and the culturing and examination of a sample of genital discharge • Antibiotics are the standard treatment • Sex partners also should be examined

Bacterial Infections Syphilis • Develops through several stages • Primary stage – painless chancre • Secondary stage – skin rash • Latent stage – 1 to 40 years • Tertiary stage – large, destructive ulcers Transmission • Most often transmitted by vaginal or anal intercourse or oralgenital or oral-anal contact • Can be transmitted by contact with a chancre • Congenital syphilis • Transmission to fetus, which can impair vision & hearing or deform bones & teeth

Syphilis – Diagnosis and Treatment Diagnosis Treatment • Primary-stage syphilis is diagnosed by a clinical exam • VDRL • Blood test named after the Venereal Disease Research Laboratory of the U. S. Public Health Service that tests for the presence of antibodies (specialized proteins that recognize and attack invading organisms or substances) to the syphilis bacterium • Penicillin and other antibiotics are the standard treatment

Bacterial Infections Chlamydia • It is more common than gonorrhea and syphilis in the US • Frequently occurs with other STIs Transmission • Vaginal or anal intercourse • Contact with the eye • Oral sex • During birth

Chlamydia – Symptoms and Treatment Symptoms • Similar to gonorrhea, but milder • In men, it can lead to nongonococcal urethritis (NGU), inflammation of the urethra • In women, chlamydial infections typically result in infections of the urethra or cervix and PID if untreated • At least 25% of men and 70% of women have no noticeable symptoms DX & Treatment • Cervical smear for women • Swab inserted through penile opening for men • Antibiotics other than penicillin are the standard treatment • Sex partners should be tested and treated, if necessary

Other Bacterial Infections Chancroid Shigellosis • Cluster of bumps or pimples on the genitals or anus, which becomes an open sore or ulcer • Also called “soft chancre” • Fever and severe abdominal symptoms Granuloma inguinale Lymphogranuloma venereum (LVG) • Painless red bumps in the groin area • Can develop into more serious symptoms if untreated • Flu-like symptoms, lymph node swelling

Critical Thinking How do penicillinresistant strains of a bacterial agent evolve?

Vaginal Infections Any type of vaginal infection or inflammation • Symptoms include • Malodorous discharge • Genital itching • Burning sensation during urination

Vaginal Infections Bacterial vaginosis Candidiasis Trichomoniasis • Usually caused by an overgrowth of bacterium • Primary symptom is discharge, but sometimes there are no symptoms • Often caused by an overgrowth of a yeast-like fungus, also called yeast infection • Symptoms include itching and a thick, curdlike discharge • Can be passed between sex partners • Caused by a protozoan and is the most common parasitic STI • Symptoms include burning, itching, painful urination, and a foamy discharge

Viral Infections Virus Tiny particles of DNA coated with a protein that cannot reproduce on their own Direct infected cells to reproduce new viral cells that spread

HIV/AIDS Human immunodeficiency virus (HIV) • A sexually transmitted virus that destroys white blood cells in the immune system, leaving the body vulnerable to lifethreatening diseases Acquired immunodeficiency syndrome (AIDS) • Condition caused by HIV • Destroys the immune system • Considered fatal

Prevalence of HIV/AIDS More than 1 million Americans living with HIV/AIDS Incidence higher in people; of color, who share needles, engaging in unprotected male-female sex Unprotected male-female sex is fastest growing exposure category Half of infected worldwide are women, but in US predominantly among men sharing needles or having sex with other men

HIV and the Immune System The immune system produces white blood cells, leukocytes, that kill pathogens Leukocytes recognize pathogens by their surface fragments, known as antigens, to which antibodies attach themselves The immune system promotes inflammation, which allows for the expanded flow of leukocytes to the region

Effect of HIV on the Immune System Spikes on the surface of HIV bind to immune system cells, CD 4 cells and others, which it uses to make copies of itself Destroys the CD 4 cells in the process HIV eventually leads to a drop in the number of CD 4 cells People are the most vulnerable to opportunistic infections when their CD 4 count falls below 200 per cubic millimeter of blood

Progression of HIV/AIDS Mild flulike symptoms may be experienced shortly after infection Most people are symptom-free for years while others may enter symptomatic state. AIDS is connected with a wasting syndrome and certain opportunistic diseases • Pneumocystis carinii pneumonia (PCP), Kaposi’s sarcoma, toxoplasmosis of the brain, and Herpes simplex • If untreated, AIDS almost always leads to death within a few years

Transmission of HIV contaminates certain bodily fluids Blood, semen, vaginal secretions, breast milk Exposure to the fluids (excluding breast milk) can occur through Vaginal, anal, or oralgenital intercourse Sharing hypodermic needles or being stuck by a needle Blood transfusions and organ and tissue transplants Artificial insemination During childbirth

Transmission of HIV Number of sexual contacts with an infected partner Type of sexual activity Genes Risk Factors The amount of virus in bodily fluid Circumcision The presence of other sexually transmitted infections

HIV is NOT Transmitted By Donating blood Casual, everyday contact Insect or animal bites Airborne germs or contact with contaminated food Sharing work or home environments Kissing

Diagnosis of HIV/AIDS Enzyme-linked immunosorbent assay (ELISA) A widely used test for HIV antibodies Performed on blood, saliva, or urine Ora. Quick A quicker antibody test

Biochemical Prevention of HIV/AIDS Currently no safe, effective vaccine despite years of research Research shows some antiviral HIV/AIDS drugs may prevent infection

Treatment of HIV/AIDS HAART “highly active antiretroviral therapy” Combination or “cocktail” of antiviral drugs Has cut US death rate by 75% since 1990 s Costly Advances in US do not extend to rest of the world

Genital Herpes simplex virus type 1 (HSV-1) Herpes simplex virus type 2 (HSV-2) Causes oral herpes Causes genital herpes • Cold sores or fever blisters on lips, in mouth, on tongue, or in throat • Painful, shallow sores and blisters on the genitals Can be transferred to the genitals by the hands or oral-genital contact Can be transferred to the mouth through oralgenital contact Incurable and lifelong

Genital Herpes Diagnosis and treatment Coping with genital herpes Involves psychological issues Clinical inspection of sores and fluid sample • A lifetime of potential recurrences, infecting sex partners, and risks when bearing children Most people learn to cope Antiviral drugs • They view herpes as a manageable illness or problem

Viral Hepatitis Inflammation of the liver • Major types are hepatitis A, hepatitis B, hepatitis C, and hepatitis D • Hepatitis B, hepatitis C, and hepatitis D can be transmitted sexually or through contact with contaminated blood Most people have no symptoms • When symptoms do appear, they often include jaundice • Yellowish discoloration of the skin and the whites of the eyes Can lead to chronic liver disease or liver cancer

Human Papilloma Virus (HPV) Causes genital warts • Warts appear around the genitals and anus • Is the world’s most common STI • Occurs most commonly in 20 - to 24 year-olds • Linked to cancers of the genital organs Can be transmitted through skin-to-skin contact during sexual activity and by touching infected towels or clothing Vaccine now available Warts can be removed (e. g. , by freezing), but there is no cure • Vaccinates against those strains responsible for cervical cancer

Molluscum Contagiosum Caused by a pox virus Painless, raised lesions appear on genitals, buttocks, thighs, or lower abdomen • Usually appear within two or three months after infection and pose no serious threat • Can disappear on their own within six months or can be removed with various solutions or by freezing them

Ectoparasitic Infections Ectoparasites Pediculosis Scabies • Parasites that live on the outside of the host’s body • May be transmitted sexually or through contact with infested towels, clothing, etc. • Infestation by pubic lice, better known as “crabs, ” that causes itching • Transmitted by contact with infested persons or objects • Infestation caused by a tiny mite that causes itching

Critical Thinking If pubic lice can be transmitted by contact with an infested toilet set, why is it referred to as a sexually transmitted infection?