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Developments in (all 30-50 or so) STDs: Global Epidemiology and Management

Developments in (all 30-50 or so) STDs: Global Epidemiology and Management

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Developments in (all 30-50 or so) STDs: Global Epidemiology and Management

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  1. Developments in (all 30-50 or so) STDs: Global Epidemiology and Management George Schmid, M.D., M.Sc. Dept of HIV WHO, Geneva

  2. Think About Training and Careers in Epidemiology and/or Public Health • The European training programme (Epiet) in epidemiology at the new European CDC, which is focusing on infectious diseases (I think this is correct) • The American training programme (EIS programme) in epidemiology at CDC • World Health Organization • Masters of science or public health degrees

  3. Morality Clinical Medicine Behaviour (change) Ethics Politics STDs: Lust Economics Love Lawsuits Surveillance Religion Lies Public health Police Sex Education Clinical Microbiology Laboratory tests Divorce Infectious diseases specialists

  4. Risk!

  5. 10% Risk

  6. 10% Risk 2% Risk 8% Risk 12% Risk 20% Risk

  7. I Have Questions for You

  8. Question #1 How many of us in this room have, or have had, an STI? 90% 75% 60% 35% 25%

  9. What Is a Sexually Transmitted Infection?

  10. What Is a Sexually Transmitted Infection? An infection which is transmitted from one person to another through acts of sex andan infection for which we want to contact the sex partner to prevent transmission to other people

  11. Sexually Transmitted Infection=Sexually Transmitted Disease=Reproductive Tract Infection?

  12. "Dear, the doctor says I have bacterial vaginosis and you need to be treated."

  13. "Dear, the doctor says I have bacterial vaginosis and you need to be treated." "My lawyer will contact you tomorrow about the divorce."

  14. RTIs STIs STDs

  15. Question #2 What proportion of cases of genital herpes are acquired from persons who know they have herpes? 85% 60% 30% 10%

  16. Asymptomatic Individuals Are Very Important • With probably every STI, except ????, most people—male and female—are asymptomatic • Asymptomatic people probably are responsible for most disease transmission • We should make people aware of these facts

  17. Chancroid Gonorrhea Syphilis Infection increasingly asymptomatic Sex practices increasingly risky Chlamydia Genital herpes Trichomonas Human papillomavirus Schmid et al. Lancet (in press)

  18. Question #3How Do We Identify Asymptomatic People? This question applies to people with STIs and persons with any other infection

  19. How Do We Identify Asymptomatic People? 1. Screening 2. Partner notification

  20. Partner Notification • How to do it? • Provider referral • Health authorities referral • Contract referral (make a "contract" with the patient to have partners into care in, e.g., 72 hours, or health authorities will contact them) • Alternate approaches • Network approach • Give patient medication for partner (for only certain diseases, e.g., chlamydia, trichomonas)

  21. Prevention of STIs is Simple • Abstinence • Mutual monogamy (with an uninfected partner) • Always use a condom • Monogamy • Limit number of sex partners • Limit number of low-quality sex partners • Have lots of sex with whomever you feel like and never use a condom People’s desire (high to low) Effectiveness (high to low)

  22. STIs There are about 30-50 STIs, or disease syndromes that result from STIs

  23. STDs Bacteria • Gonorrhea (Neisseria gonorrhoeae) • Chlamydia (Chlamydia trachomatis) • Syphilis (Treponema pallidum) • Chancroid (Haemophilus ducreyi) Viruses • Genital warts and cervical—mainly--cancer (human papillomavirus) • Genital herpes (herpes simplex virus) • Hepatitis B (hepatitis B virus) Parasites • Trichomoniasis (Trichomonas vaginalis)

  24. Why Do We Care About STIs?

  25. Why Do We Care About STIs? • Acute morbidity • Late morbidity • Spread locally, e.g., • 10-40% of women with a gonococcal or chlamydial infection develop PID. Of women with one episode of PID: • 20% are infertile • Of those who become pregnant, 9% will have an ectopic pregnancy

  26. Why Do We Care About STIs (continued)? • Late morbidity (continued) • Spread in body, e.g., • 30% of individuals with untreated syphilis develop neurosyphilis, cardiovascular syphilis, or late benign syphilis • Disseminated gonococcal infection (DGI) • Adverse outcomes of pregnancy, i.e., • Infertility • Affect the pregnancy, i.e., miscarriage, congenital infection • Affect the baby at delivery, e.g., genital herpes, chlamydia

  27. Why Do We Care About STIs (continued)? • Cofactors for cancer • Cervical cancer (HPV, probably HSV) and anal and penile cancer (HPV) • Hepatic cancer (hepatitis B and hepatitis C) • Enhanced HIV transmission

  28. What Characterizes STIs? • Inflammation • Increased numbers of white blood cells, exudates • With some STIs, preferential recruitment of CD4-antigen bearing cells • Breaks in mucosa or skin • Bleeding

  29. Evidence for the Enhancement of HIV Infection by STIs • Cross-sectional studies • Cohort studies • Biologic studies

  30. Cohort Study, Nairobi • 73 HIV-negative men with an STD • All men had had one act of sexual intercourse with a prostitute • The men were counseled, given condoms, told to avoid sex with prostitutes, and followed every 2 weeks for three months for HIV seroconversion • 85% of prostitutes were HIV-positive Cameron WD et al. Lancet 1989;2:403

  31. Proportion of Men Developing HIV Infection After a Single Act of Sexual Intercourse Attributable risk due to lack of circumcision and genital ulcer=98% Cameron WD et al. Lancet 1989;2:403

  32. Presence of HIV in Ulcer Secretions 1 Kreiss J et al. J Infect Dis 1989;160:380 2 Plummer FA et al. J Infect Dis 1990;161:810 3 Mertz KJ et al. J Infect Dis 1998;178:1795 4 Schacker T et al. JAMA 1998;280:61

  33. How Common Are STIs Globally? No one knows

  34. Estimated Incidence of STIs, by Continent Delebatta G et al. Family Health International

  35. Estimated prevalence (per 1000) of STIs by region in 1999

  36. Why Do People Get STIs?

  37. Anderson-May Equation Ro = reproductive rate $ =infectivity c = rate of partner change (sex, needle) D = duration of infectiousness Ro = $c D

  38. Percentage of population Core group Number of partners

  39. Diseases and Syndromes 30-50 organisms or syndromes that are sexually transmitted

  40. Test!

  41. Proportion of Men with Either Gonorrhea or Nongonococcal Urethritis, by Type of Discharge Swartz SL et al. J Infect Dis 1978;138:445

  42. Ability of Clinicians to Diagnose the Cause of a Genital Ulcer Dangor Y et al. Sex Transm Dis 1990;17:184

  43. STI Syndromes • No symptoms or signs • Urethral discharge/discomfort (urethritis) in males • N. gonorrhoeae • C. trachomatis • U. urealyticum • Testicular pain (epididymitis) • N. gonorrhoeae • C. trachomatis • Abdominal pain in women (pelvic inflammatory disease) • N. gonorrhoeae • C. trachomatis • Flora of bacterial vaginosis • ? Mycoplasma genitalium

  44. STI Syndromes (con’t) • Vaginal discharge/inflammation in women • Trichomonas vaginalis • Candida species (candidiasis) • Bacterial vaginosis • Genital “growths” • Human papillomavirus • Genital ulcers • Herpes simplex virus • Haemophilus ducreyi • Treponema pallidum

  45. STI Syndromes (con’t) • Inguinal adenopathy • Chlamydia trachomatis (LGV) • Haemophilus ducreyi

  46. Diseases Characterized by Genital Ulcers • Chancroid • Syphilis • Genital herpes • Other infectious causes of ulcers: • Epstein-Barr virus • Cytomegalovirus • Noninfectious causes, e.g. • Fixed drug eruption (tetracycline, laxatives commonly cause) • Trauma

  47. Diagnostic Tests for Genital Ulcers • History and physical exam! • Laboratory • Darkfield microscopy (syphilis) • RPR syphilis serology • About 70% sensitive in primary syphilis (if negative today, repeat in one week) • Test for herpes • Culture, antigen tests, PCR Exclude syphilis!

  48. Syphilis • Serology, with the screening RPR and a confirmatory, treponemal test (TPPA), is the mainstay of diagnosis • Works because the average incubation period for primary syphilis is 21 days and the average person waits 7 days before coming in—this 28-day period allows time for antibody to be developed • “Strip” or “dip-stick” rapid tests, all based on treponemal antigen, are available

  49. Syphilis Therapy • For early syphilis*, a single dose of benzathine penicillin, 2.4 million units, intramuscularly Or • Procaine penicillin, 600,000 units daily intramuscularly for 10-14 days • See monthly for 3 months, then at 6 and 12 months for repeat RPR titers to document a four-fold decline, that is, cure. *Syphilis of one year’s duration or less All therapy guidance from: European STD Guidelines. Int J STD AIDS 2001;12S3.

  50. Question #4 HPV is a life-long infection True False HSV-2 is a life-long infection True False