Clinical syndromes in infectious diseases
Trichomoniasis: Trichomonas vaginalis
Overview Classic exogenous sexually transmitted infection Epidemiology Prevalence difficult to ascertain because it is not reportable ~ 4 million people in U.S. have trichomoniasis with 1.1 million new cases per year Prevalence 3% among reproductive age women but 4x higher in non-Hispanic black women (highest risk group) 25% of sexually active women become infected at […]
Vaginal candidiasis: Candida albicans
Overview Besides vulvovaginitis, candidiasis can cause diaper rash, oral thrush, urinary tract infections, pneumonia and bloodstream infection. Epidemiology Infections are often from endogenous flora 75% of women will have at least one episode of vulvovaginitis in their life Candida albicans responsible for 85 to 95% of cases of vulvovaginal candidiasis in U.S., remainder due to […]
Bacterial vaginosis (BV): Gardnerella vaginalis, anaerobes
Epidemiology Gardnerella can be isolated in 50% of asymptomatic women Not technically a sexually transmitted disease however: Positive association between BV and multiple sexual partners Negative association between BV and condom usage Microbiology and pathogenesis Definitive explanation of the pathogenesis of bacterial vaginosis remains elusive Displacement of the normal lactobacilli in the vagina by Gardnerella […]
Vaginal discharges/Vaginitis
Background Vagina contains a normal resident microbial flora Physiologic vaginal fluid is clear, white, odorless with a high viscosity Lactobacilli dominate the resident microflora and keep pathogens in check by Converting glycogen to lactic acid maintaining the normal pH acidic between 3.8 and 4.5 Producing hydrogen peroxide that kills pathogenic bacteria and viruses The […]
Gonorrhea: Neisseria gonorrhoeae (Gonococcus)
Epidemiology Probably underreported Highest rates in women ages 15–19 and men ages 20–24 95% of men are symptomatic 50% of women are symptomatic Major reservoir for transmission is asymptomatic patients Lack of immunity means repeat infections are the rule Transmissions rates: Male to female 50–70% and female to male 20% per sexual intercourse episode Gonococcal […]
Nongonococcal urethritis (NGU): Chlamydia trachomatis, serovar D-K
Epidemiology Most common reportable bacterial STI in U.S. Prevalence highest in sexually active females, ages 15-24 Disproportionate burden/higher incidence in African-Americans Microbiology and pathogenesis Obligate intracellular bacterium with a cell wall and ribosomes like those of gram-negative organisms Obligate because it relies on the host cell for key amino acids and energy generating ATP Cell […]
Human papillomavirus (HPV)
Overview VIRUS SIZE HUMAN SUBTYPES TRANSMISSION DISEASE TREATMENT PREVENTION Papillomavirus 55 nm HPV-1-4, 7, 10 Close skin-to-skin contact, occupational exposure, public shower/swimming pool Skin warts Common warts Plantar warts Flat cutaneous warts Meat/fish handler warts Topical cytotoxins or surgical removal Papillomavirus 55 nm HPV-6, 11 Close contact, sexual contact Oral, laryngeal papillomatosis Genital warts […]
Granuloma inguinale (Donovanosis): Klebsiella granulomatis
Overview Donovanosis is a chronic, progressive ulcerative disease of the skin and subcutaneous tissues. Commonly referred to as granuloma inguinale, but because this term can easily be confused with LGV, many experts now recommend using “donovanosis”. Epidemiology Uncommon in developed, nontropical settings. Sporadically reported from Papua New Guinea, South Africa, India, Brazil, and Australia. Microbiology […]
Lymphogranuloma venereum (LGV): Chlamydia trachomatis serovar L1–L3
Overview LGV is uncommon in the U.S. It is caused by Chlamydia trachomatis serovar L1-L3. The much more common STI in the U.S. is nongonococcal urethritis (NGU) caused by Chlamydia trachomatis serovar D-K. (See section on Nongonococcal urethritis for in-depth microbiology of Chlamydia) As background, Chlamydia has three species with characteristics and pathogenicity outlined in […]