The Major STDs Also known as sexually transmitted

The Major STDs Also known as sexually transmitted infections (STIs) Spread of an infection from person to person mainly through sexual activity STDs that pose a major health threat: 1. 2. 3. 4. 5. 6. 7. HIV/AIDS Hepatitis Syphilis Chlamydia Gonorrhea Herpes Human papillomavirus (HPV) CDC (2008) estimated 65 million Americans were infected with an STD, and about 19 million Americans become newly infected with an STD each year © 2012 Mc. Graw-Hill Companies. All Rights Reserved 1

HIV Infection and AIDS Human immunodeficiency virus (HIV) is the virus which causes AIDS (acquired immunodeficiency syndrome) Without treatment, AIDS kills nearly all of its victims Approximately 65 million people around the world have been infected with HIV since the epidemic began Nearly 1% of the world’s population About 3. 5 million new infections per year 21% of HIV-infected Americans are unaware of their condition © 2012 Mc. Graw-Hill Companies. All Rights Reserved 2

What Is HIV Infection? Chronic disease that progressively damages the body’s immune system HIV attacks and invades CD 4 T-cells and other essential elements of the immune system HIV enters a human cell and converts its own genetic material, RNA, into DNA Inserts this DNA into chromosomes of host cell The viral DNA takes over the CD 4 cell and replicates, destroys the immune functions of CD 4 cell People with AIDS are vulnerable to a number of serious opportunistic (secondary) infections Once initial symptoms resolve, the asymptomatic period, also called the latency phase, may last from 2 to 20 years © 2012 Mc. Graw-Hill Companies. All Rights Reserved 3

Transmitting the Virus HIV lives only within cells and body fluids Three primary means of transmission: Specific kinds of sexual contact Direct exposure to infected blood HIV-infected women to her fetus or to infant during breastfeeding Not through casual contact © 2012 Mc. Graw-Hill Companies. All Rights Reserved 4

Populations of Special Concern for HIV Infection Most common means of exposure: Sexual activity between men Injection drug use Heterosexual contact African American men and women are vastly overrepresented among people newly diagnosed with AIDS Increasingly a disease that effects minorities, women, and the poor © 2012 Mc. Graw-Hill Companies. All Rights Reserved 5

Figure 13. 3 Routes of HIV transmission among Americans © 2012 Mc. Graw-Hill Companies. All Rights Reserved 6

Symptoms of HIV Infection Within a few days or weeks (on average, 2 to 4 weeks after exposure to the virus), some people will develop symptoms of primary (acute) HIV infection Specialized test HIV RNA assay Symptoms take months or years to develop, but as immune system weakens, variety of symptoms develop Swollen lymph nodes Lumps, rashes, sores Pneumocystis pneumonia (fungal infection) Kaposi’s sarcoma Difficult-to-treat yeast infections in women Tuberculosis Weight loss, fevers, sweats © 2012 Mc. Graw-Hill Companies. All Rights Reserved 7

Diagnosing HIV Infection Most common tests check for the presence of antibodies to the virus HIV antibody tests ELISA (first test) Western blot or immunoflourescence assay is done to confirm results If HIV-positive, the next step is to determine the disease’s severity to plan appropriate treatment © 2012 Mc. Graw-Hill Companies. All Rights Reserved 8

Treatment Antiviral drugs Reverse transcriptase inhibitors Protease inhibitors Entry inhibitors HAART and Postexposure Prophylaxis (PEP) Treatments for opportunistic infections HIV and pregnancy Treatment challenges How can you protect yourself? © 2012 Mc. Graw-Hill Companies. All Rights Reserved 9

Figure 13. 4 What’s risky and what’s not: The approximate relative risk of HIV transmission of various sexual activities © 2012 Mc. Graw-Hill Companies. All Rights Reserved 10

Chlamydia Most prevalent bacterial STD in the U. S. Can cause sterility in men and women In women, it can lead to pelvic inflammatory disease, infertility and ectopic (tubal) pregnancy In men, chlamydia is the most common cause of epididymitis (inflammation of sperm-carrying ducts), and causes half of all cases of urethritis (inflammation of the urethra) Symptoms Usually asymptomatic in women, some have vaginal discharge, burning with urination, pain or bleeding with intercourse, and lower abdominal pain In men, painful urination, watery discharge from penis, pain around testicles and in lower abdominals © 2012 Mc. Graw-Hill Companies. All Rights Reserved 11

Chlamydia Diagnosis and treatment Laboratory tests on a urine sample or a small amount of fluid from the urethra or cervix Once diagnosed, infected person and partner are given antibiotics Expedited partner therapy © 2012 Mc. Graw-Hill Companies. All Rights Reserved 12

Gonorrhea 330, 000 new cases reported to the CDC in 2008 Can cause arthritis, rashes, eye infections, PID, epididymitis, urethritis, and gonococcal conjunctivitis or gonorrheal infection of blood or joints in infants of infected mothers Can infect throat or rectum through oral or anal sex Symptoms Usually asymptomatic in women, may have painful urination, increased vaginal discharge, and severe menstrual cramps Thick yellow-white discharge, and painful urination in men, lips of urethral opening might become inflamed and swollen, lymph glands in groin may become enlarged and swollen, half of men have minor or no symptoms © 2012 Mc. Graw-Hill Companies. All Rights Reserved 13

Gonorrhea Diagnosis and treatment Microscopic exam of discharge can diagnose infection Oral antibiotics can cure the disease ○ Growing number of drug-resistant strains of gonorrhea is a major concern, only 1 class of antibiotics remains consistently effective © 2012 Mc. Graw-Hill Companies. All Rights Reserved 14

Pelvic Inflammatory Disease (PID) Occurs when initial infection by chlamydia or gonorrhea travels upwards into reproductive organs Often serious enough to require hospitalization and surgery 25% of affected women have long-term problems Leading cause of infertility in young women Smoking, large number of sexual partners, and IUD usage are all risk factors for infection © 2012 Mc. Graw-Hill Companies. All Rights Reserved 15

Pelvic Inflammatory Disease (PID) Symptoms Women can be asymptomatic Long and painful periods, discharge, spotting, abdominal pain, fever, chills, nausea, and vomiting Diagnosis and treatment Diagnosis made on basis of symptoms, physical examination, ultrasound, and laboratory tests, may require laparoscopy Antibiotics and sometimes hospitalization are required for treatment Very important that partners be treated, many men asymptomatic © 2012 Mc. Graw-Hill Companies. All Rights Reserved 16

Human Papillomavirus (HPV) Most common STD in the U. S. Causes a variety of human diseases: Common warts Genital cancers Highly contagious, can spread through oral sex Very common among young people Two vaccines for HPV: Gardasil and Cervarix Gardasil ○ Protects against four types of HPV virus that account for 90% of genital warts and 70% of cervical cancers ○ Most effective before the onset of sexual activity ○ Approved for boys and men Cervarix ○ Doesn’t protect against genital warts, but may be more effective in protections against cervical cancer © 2012 Mc. Graw-Hill Companies. All Rights Reserved 17

Human Papillomavirus (HPV) Symptoms Small bump on the skin or a large, warty growth Cauliflower-like mass May cause irritation and bleeding , painful urination Diagnosis and treatment Diagnosed based on the appearance of lesions Often detected during routine PAP tests Special tests can detect HPV and distinguish among the more common strains, including those that cause most cases of cervical cancer Treatment focuses on reducing the number and size of warts ○ Cryosurgery (freezing) ○ Electrocautery (burning) ○ Laser surgery ○ Acid treatments © 2012 Mc. Graw-Hill Companies. All Rights Reserved 18

Genital Herpes 1 in 5 adults in the U. S. has genital herpes Two forms cause genital herpes and oral-labial herpes (cold sores) HSV 1 (Type 1) ○ Usually exposed to virus during childhood ○ Oral-labial herpes (cold sores) ○ 50 -80% of U. S. adults have antibodies to HSV-1 HSV 2 (Type 2) ○ Almost always sexually transmitted ○ Usually occurs during adolescence and early adulthood ○ Asymptomatic in 80 -90% of people If you ever have an outbreak, consider yourself always contagious and inform partners © 2012 Mc. Graw-Hill Companies. All Rights Reserved 19

Genital Herpes Symptoms 90% of infected people have no symptoms First episode causes flulike symptoms and genital lesions Recurrent outbreaks Diagnosis and treatment Diagnosed through symptoms, physical examination, lab tests No cure, carry virus for life Antiviral drugs taken at the beginning of an outbreak can shorten the severity and duration of symptoms Vaccines are in development © 2012 Mc. Graw-Hill Companies. All Rights Reserved 20

Hepatitis B (HBV) Inflammation of the liver which can cause serious and permanent damage to the liver Highly contagious but preventable with vaccine Transmitted through the exchange of bodily fluids and sharing needles or contaminated items Can spread through nonsexual close contact Symptoms Can be asymptomatic Flulike symptoms, nausea, vomiting, dark-colored urine, abdominal pain, and jaundice Diagnosis and treatment Diagnosed through blood tests Most people recover, but can be chronic carriers Can be fatal, no cure © 2012 Mc. Graw-Hill Companies. All Rights Reserved 21

Syphilis Caused by bacterium: Treponema pallidum Can be effectively treated with antibiotics Symptoms Primary phase: 10 -90 days after exposure ○ Characterized by painless ulcers, called chancres, highly contagious Secondary phase: 3 -6 weeks after chancre ○ Characterized by flulike symptoms and highly contagious skin rash Late, or tertiary, phase ○ Damage to organs, dementia, cardiovascular damage, blindness, and death Diagnosis and treatment Diagnosed by examination of infected tissues and with blood tests Treated by antibiotics but damage from late stages of infection can be permanent © 2012 Mc. Graw-Hill Companies. All Rights Reserved 22

Other STDs Trichomoniasis Most common curable STD among young women Single-celled organism Bacterial vaginosis (BV) Most common cause of abnormal vaginal discharge Caused by unhealthy species of normal vaginal bacteria Pubic lice and scabies Contagious parasitic infections © 2012 Mc. Graw-Hill Companies. All Rights Reserved 23

What You Can Do Education Diagnosis and treatment Get vaccinated Be alert for symptoms Get tested Inform your partners Get treated Prevention Think and talk about responsible sexual behavior © 2012 Mc. Graw-Hill Companies. All Rights Reserved 24

Chapter 13 Immunity and Infection © 2012 Mc. Graw-Hill Companies. All Rights Reserved 25