1 Sexually Transmitted Infections Chapter 24

Mosby items and derived items © 2006 by Mosby, Inc. 2 Sexually Transmitted Urogenital Infections  Bacterial infections Gonorrhea  Caused by microorganisms of the species Neisseria gonorrhoeae Aerobic, non–spore-forming, gram-negative, diplococcus  Transmission generally requires contact of epithelial surfaces  Gonorrhea also crosses amniotic membranes  Humans are the only natural hosts

Mosby items and derived items © 2006 by Mosby, Inc. 3 Sexually Transmitted Urogenital Infections  Gonorrhea Presence of pili helps the microorganisms attach themselves to the epithelial cells of mucous membranes Infections can result in:  Disseminated gonococcal infection (CGI)  Perihepatitis  Ophthalmia neonatorum

Mosby items and derived items © 2006 by Mosby, Inc. 4 Sexually Transmitted Urogenital Infections  Syphilis Treponema pallidum  Corkscrew-shaped, anaerobic bacterium that cannot be cultured in vitro  Infects any body tissue  Syphilis becomes a systemic disease shortly after infection. Maternal-fetal transmission

Mosby items and derived items © 2006 by Mosby, Inc. 5 Syphilis  Stages Primary syphilis  Local manifestations Granulomatous tissue reaction—hard chancre Microorganisms drain with the lymphatic fluid Secondary syphilis  Systemic manifestations Fever, malaise, sore throat, hoarseness, anorexia, joint pain, skin rash, and lesions (condylomata lata)

Mosby items and derived items © 2006 by Mosby, Inc. 6 Syphilis  Stages Latent syphilis  Medical evidence of the infection, but patient is asymptomatic Tertiary syphilis  Most severe stage  Formation of gummas Destructive skin, bone, and soft tissue lesions  Destructive systemic manifestations

Mosby items and derived items © 2006 by Mosby, Inc. 7 Syphilis  Congenital syphilis Vasculitis, necrosis, fibrosis, and generalized tissue destruction Manifest in the first 2 years of life Late stage manifestations occur near puberty

Mosby items and derived items © 2006 by Mosby, Inc. 8 Sexually Transmitted Urogenital Infections  Chancroid Typical in underdeveloped or developed tropical climates Painful, tender, soft chancre Acute infectious disease caused by Haemophilus ducreyi  Gram-negative bacillus Inguinal buboes

Mosby items and derived items © 2006 by Mosby, Inc. 9 Chancroid

Mosby items and derived items © 2006 by Mosby, Inc. 10 Sexually Transmitted Urogenital Infections  Granuloma inguinale Chronic, progressive, destructive bacterial infection  Caused by Klebsiella granulomatis; gram-negative, non–spore-forming, encapsulated bacillus  Mildly contagious; repeated exposure is required  Concurrent infection with syphilis is common  Does not occur in the United States  Donovan bodies Bacteria-filled vacuoles within white cells

Mosby items and derived items © 2006 by Mosby, Inc. 11 Sexually Transmitted Urogenital Infections  Bacterial vaginosis Sexually associated condition, but not always an STI Caused by Gardnerella vaginalis and various other anaerobes Manifestations  Gray vaginal discharge, pH > 4.5, odor, presence of “clue” cells on wet mount Bacterial catalytic enzymes degrade proteins and elevate the vaginal pH to produce a fishy odor Clue cells are vaginal epithelial cells covered with bacteria

Mosby items and derived items © 2006 by Mosby, Inc. 12 Chlamydial Infections  Chlamydia Infections caused by Chlamydia trachomatis Most common STI in the United States Obligate, gram-negative, intracellular bacterium Growth cycle (two parts)  Elementary body Small, resilient, metabolically inert, able to survive extracellularly  Metabolically active parasite

Mosby items and derived items © 2006 by Mosby, Inc. 13 Chlamydial Infections  Lymphogranuloma venereum Caused by Chlamydia trachomatis (invasive serovars of strains L1, L2, and L3) Chronic STI Begins as a skin lesion and spreads to genital and rectal lymphatic tissue  Inflammation, necrosis, buboes, abscesses, and infections  Can spread to the CNS

Mosby items and derived items © 2006 by Mosby, Inc. 14 Chlamydial Infections  Nongonococcal or nonspecific urethritis Nonreportable STI Syndrome caused by a variety of microbes  Most common is C. trachomatis  Trichomonas vaginalis, herpes simplex virus, Ureaplasma urealyticum, and Mycoplasma

Mosby items and derived items © 2006 by Mosby, Inc. 15 Sexually Transmitted Viral Infections  Genital herpes Two serotypes  Herpes simplex virus type 1  Herpes simplex virus type 2 80% of initial and 98% of recurrent infections are type 2 Not a reportable disease Transmitted through contact with a person who is shedding the virus in a secretion or from a peripheral lesion or mucosal surface

Mosby items and derived items © 2006 by Mosby, Inc. 16 Sexually Transmitted Viral Infections  Genital herpes Initial virus replication occurs locally Virus spreads to contiguous cells and into sensory nerves Virus is transported intraaxonally to the dorsal root

Mosby items and derived items © 2006 by Mosby, Inc. 17 Sexually Transmitted Viral Infections  Genital herpes Virus remains latent until reactivated  Oral infection Virus resides in the trigeminal ganglion  Genital infection Virus resides in the dorsal sacral nerve roots

Mosby items and derived items © 2006 by Mosby, Inc. 18 Sexually Transmitted Viral Infections  Human papillomavirus (HPV) 120 different types of HPV  30 serotypes are unique to stratified squamous epithelium  Divided into high-risk and low-risk serotypes HPV is a nonenveloped, circular double-stranded DNA virus Belongs to the Papovaviridae family

Mosby items and derived items © 2006 by Mosby, Inc. 19 Sexually Transmitted Viral Infections  Human papillomavirus (HPV) Condylomata acuminata (genital warts)  Soft, skin-colored, whitish pink to reddish brown benign growths caused by HPV Treatment is considered cosmetic, not curative

Mosby items and derived items © 2006 by Mosby, Inc. 20 Sexually Transmitted Viral Infections  Molluscum contagiosum Benign viral infection of the skin Primarily infects the face, hands, lower abdomen, and genitalia Taken into epithelial cells by phagocytosis  Replicates to produce molluscous bodies

Mosby items and derived items © 2006 by Mosby, Inc. 21 Sexually Transmitted Parasitic Infections  Trichomoniasis Caused by Trichomonas vaginalis  Anaerobic, unicellular, flagellated, parasitic protozoan Adheres to and damages squamous epithelial cells  Urethra, vagina, and Skene and Bartholin glands Accounts for 25% of infectious vaginitis cases Often coexists with gonorrhea Presence confirmed by microscopic examination of vaginal secretions or urine

Mosby items and derived items © 2006 by Mosby, Inc. 22 Sexually Transmitted Parasitic Infections  Scabies Caused by the adult female itch mite, Sarcoptes scabiei Transmission of scabies requires prolonged close skin-to-skin contact  Typically occurs between family members or sexual partners Burrows though the horny layer of the stratum per day  New larval forms appear in about 10 days Classic symptom is intense pruritus

Mosby items and derived items © 2006 by Mosby, Inc. 23 Scabies

Mosby items and derived items © 2006 by Mosby, Inc. 24 Sexually Transmitted Parasitic Infections  Pediculosis pubis Caused by the crab louse Phthirus pubis Transmitted primarily by intimate sexual contact or contact with infected bed linens or clothing A crab louse has a 25- to 30-day life cycle  Stages: egg or nit, three nymphal stages, and an adult stage Symptoms  Mild to severe itching, allergic sensitization, and secondary infections from scratching

Mosby items and derived items © 2006 by Mosby, Inc. 25 Pediculosis Pubis

Mosby items and derived items © 2006 by Mosby, Inc. 26 Sexually Transmitted Gastrointestinal Infections  Shigellosis and Campylobacter enteritis  Giardiasis and amebiasis  Hepatitis B

Mosby items and derived items © 2006 by Mosby, Inc. 27 Sexually Transmitted Systemic Diseases  Epstein-Barr virus  Acquired immunodeficiency syndrome  Cytomegalovirus