<p> Sexually Transmitted Infections</p><p>STIs disproportionately affect teens & young adults • 19 million new cases of STIs in U.S. each year – 9 million (48%) are among 15 – 24 years olds • 3 infections account for the great majority of cases in this group – genital warts – trichomoniasis – chlamydia • 3 STIs are frequent among college students – chlamydia – genital warts – herpes</p><p>“Nuisance STIs” • trichomoniasis – caused by protozoan – transmitted mainly through intercourse – discharge evident in both men & women (although some men may be asymptomatic) – if untreated, can lead to P.I.D. & increased susceptibility to HIV infection • pubic lice (crabs) – not a disease, but transmitted by sexual contact • vaginitus (vaginal infection or irritation) – two types, very common & endemic in college populations – not STIs because they are not transmitted by sexual contact, however, they are infections of the sexual organs </p><p>Bacterial STIs • curable with antibiotic treatment • chlamydia – 1,100,000 new cases per year in U.S. • more prevalent in higher socioeconomic groups, university students, adolescent girls – 75% of cases in women & 50% of cases in men are asymptomatic • results in PID and sterility in women if untreated • gonorrhea – 350,000 cases cases per year in U.S. • resurgence of cases in late 20th century – 60-80% of cases in women are asymptomatic • results in PID and sterility if untreated • syphilis – 11,500 reported new cases in 2007 • sharp decline from early 1990s; lowest rate since reporting began in 1941 occurred in 2000, some increase since then – increased susceptibility to HIV infection – progresses through 4 stages if untreated • primary, secondary, latent, late Viral STIs • not curable (drugs used to control or suppress symptoms) • HPV (genital warts) – 35% of 14 – 19 year-olds are infected – majority of people infected are asymptomatic – most important risk factor for cervical cancer • vaccine available to prevent some strains • HSV-2 (genital herpes) – 17% of Americans are infected w/HSV-2 (58% infected w/HSV-1) – majority of people infected are asymptomatic – can be transmitted even when there is no active outbreak of blisters – increased susceptibility to HIV infection • HBV (hepatitus B or viral hepatitus) – transmitted through body fluids – vaccine available (for prevention, not cure)</p><p>HIV Infection and AIDS • human immune deficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS) • by end of 2006 about 1 million Americans had been diagnosed with AIDS (550,000 of them died) • transmitted by exchange of body fluids – semen, blood, & possibly secretions of cervix & vagina – worldwide, majority of cases result from heterosexual transmission • factors which increase risk of becoming infected – anal intercourse – greater number of sexual partners – sex w/infected partner, sex w/partner from high risk group, sex w/o condom • disproportionate impact on women, children, people of color</p>