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George Schmid HIV/AIDS Department

Global incidence and prevalence of four curable sexually transmitted infections (STIs): New estimates from WHO March, 2009. George Schmid HIV/AIDS Department. STIs "are alive and well" in 2005. There are over 20 STIs. STDs/STIs. Bacteria Gonorrhea ( Neisseria gonorrhoeae )

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George Schmid HIV/AIDS Department

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  1. Global incidence and prevalence of four curable sexually transmitted infections (STIs): New estimates from WHOMarch, 2009 George Schmid HIV/AIDS Department

  2. STIs "are alive and well" in 2005

  3. There are over 20 STIs

  4. STDs/STIs 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) • Pubic lice (Phthirus pubis)

  5. Global prevalence and incidence of four curable STIsMarch, 2009 D r a f t George Schmid, Jane Rowley, Julie Samuelson, Ye Tun, Txema Garcia-Calleja, Francis Ndowa, with thanks to some of you here….

  6. My "take-home message" We need better data

  7. 1995 and 1999 Incidence Estimates* *15-49 year-old population

  8. Incidence of Four Curable STIs, by Region, 1999 Glasier A et al. Lancet 2006;268:1-12

  9. 2005 WHO Estimates Process • Literature search for studies conducted 2000-2005 • Data on incidence and prevalence • Published and grey literature (including DHS) • Quality filter • At least 100 persons • No apparent bias in population selection • High quality laboratory testing • Incidence=prevalence/duration • Modelling approach same as 1999 (and 1995), but explicitly adjusted for… • Age • Female chlamydia prevalence • Urban:rural • High risk populations • Sensitivity and specificity of laboratory tests • (Duration parameters changed) • Changed region estimations to WHO regions

  10. Some Important Parameters • D = S * [VS * TS + (1 - VS) * US] + (1 – S) * [VA * TA + (1 – VA) * UA] • S is the probability an infected individual is symptomatic • VS is the probability an infected symptomatic individual is treated (by region) • TS is the average duration of infection for symptomatic individuals who are treated (by region) • US is the average duration of infection for symptomatic individuals who are not treated • VA is the probability an infected asymptomatic individual is treated (by region) • TA is the average duration of infection for asymptomatic individuals who are treated (by region) • UA is the average duration of infection for asymptomatic individuals who are not treated • Did review for sensitivity and specificity of laboratory tests, e.g. Specimen (sex) Test Sensitivity Specificity Urine (men) NAAT 87.8% 99.3% … … … …

  11. Global total incidence estimate of selected STIs, 2005 Infection in females (left) and males (right)

  12. Global estimated total of selected STIs, prevalence 2005 Total number of cases 32 900 000 Female 25 485 560 Male 7 464 716 Total number of cases 5 400 000 Female 3 662 021 Male 1 737 246 Total number of cases 17 100 000 Female 12 134 932 Male 4 967 604 Total number of cases 77 400 000 Female 54 025 046 Male 23 399 348 Total number of cases 54 400 000 Female 38 364 356 Male 16 075 855 Total number of cases 61 000 000 Female 46 955 091 Male 14 072 815 Total number of cases 72 700 000 Female 50 403 262 Male 22 303 258 Total number of cases 321 100 000 Female 231 030 267 Male 90 020 841

  13. Global estimated total of selected STIs, incidence 2005 Total number of cases 52 000 000 Female 26 583 505 Male 25 397 743 Total number of cases 8 600 000 Female 4 330 377 Male 4 231 056 Total number of cases 25 400 000 Female 2 597 979 Male 3 913 178 Total number of cases 108 600 000 Female 56 064 831 Male 52 530 179 Total number of cases 70 700 000 Female 30 128 032 Male 40 602 390 Total number of cases 80 600 000 Female 39 564 409 Male 41 060 391 Total number of cases 111 300 000 Female 39 460 792 Male 71 803 576 Total number of cases 457 200 000 Female 207 594 580 Male 249 524 252

  14. Global estimated incidence of chlamydia, 2005 Total number of cases 15 200 000 Female 9 033 810 Male 6 174 402 Total number of cases 4 200 000 Female 2 076 224 Male 2 076 224 Total number of cases 5 700 000 Female 2 597 979 Male 3 064 969 Total number of cases 41 600 00 Female 20 378 895 Male 21 217 026 Total number of cases 6 600 000 Female 4 007 640 Male 2 603 721 Total number of cases 18 300 000 Female 10 078 288 Male 8 183 915 Total number of cases 10 000 000 Female 5 823 663 Male 4 151 561 Total number of cases 101 500 000 Female 53 996 501 Male 47 471 820

  15. 80.00 70.00 60.00 50.00 Incidence per 1000 40.00 30.00 20.00 10.00 0.00 AFRO EMRO PAHO SEARO WPRO EURO North Global total America Region, female (left) and male (right) Global incidence estimate of chlamydia, 2005

  16. Global estimated incidence of gonorrhea, 2005 Total number of cases 12 000 000 Female 4 806 384 Male 7 203 615 Total number of cases 700 000 Female 362 883 Male 334 440 Total number of cases 6 500 000 Female 2 569 269 Male 3 913 178 Total number of cases 26 900 000 Female 16 470 615 Male 10 407 556 Total number of cases 22 700 000 Female 7 111 523 Male 15 545 316 Total number of cases 8 800 000 Female 2 820 693 Male 5 955 327 Total number of cases 17 300 000 Female 7 921 524 Male 9 362 908 Total number of cases 94 800 000 Female 42 062 894 Male 52 722 343

  17. 60.00 50.00 40.00 Incidence per 1000 30.00 20.00 10.00 0.00 AFRO EMRO PAHO SEARO WPRO EURO North Global total America Region, female (left) and male (right) Global incidence estimate of gonorrhea, 2005

  18. Global estimated incidence of syphilis, 2005 Total number of cases 303 000 Female 150 888 Male 152 011 Total number of cases 43 000 Female 9 040 Male 34 234 Total number of cases 587 000 Female 287 292 Male 299 966 Total number of cases 1 052 000 Female 517 819 Male 533 778 Total number of cases 2 847 000 Female 1 449 089 Male 1 398 137 Total number of cases 2 350 000 Female 1 151 222 Male 1 198 596 Total number of cases 3 496 000 Female 1 527 061 Male 1 969 653 Total number of cases 10 680 000 Female 5 092 414 Male 5 586 377

  19. 12.00 10.00 8.00 Incidence per 1000 6.00 4.00 2.00 0.00 AFRO EMRO PAHO SEARO WPRO EURO North Global total America Region, female (left) and male (right) Global incidence estimate of syphilis, 2005

  20. Global incidence of trichomonas, 2005 Total number of cases 24 500 000 Female 12 592 421 Male 11 867 713 Total number of cases 3 700 000 Female 1 882 229 Male 1 786 156 Total number of cases 12 600 000 Female 6 008 092 Male 6 620 803 Total number of cases 39 100 000 Female 18 697 500 Male 20 371 817 Total number of cases 38 000 000 Female 17 559 778 Male 21 055 214 Total number of cases 51 200 000 Female 25 514 204 Male 25 722 550 Total number of cases 80 500 000 Female 24 188 543 Male 56 319 453 Total number of cases 250 200 000 Female 106 442 769 Male 143 743 711

  21. 350.00 300.00 250.00 200.00 Incidence per 1000 150.00 100.00 50.00 0.00 AFRO EMRO PAHO SEARO WPRO EURO North Global total America Region, female (left) and male (right) Global incidence estimate of trichomonas, 2005

  22. Global estimated totals of selected STIs, incidence 2005 Chlamydia 101 468 321 Gonorrhea 94 785 238 Syphilis 10 678 792 Trichomonas 250 186 481

  23. Data Needs • Better data are needed in all areas that go into the estimations process, e.g. • Duration parameters • Urban:rural adjustment, etc • BUT, biggest need is in studies of prevalence • Often, only several studies in sub-regions, e.g., may need to generate estimates for West Africa on one study in Nigeria and one in Senegal

  24. Warning • Comparing the 2005 figures with the 1999 figures is hazardous: • Data sources variable • New estimations made for parameters used in both processes, e.g., some of the duration figures • New parameters inserted, e.g., adjustment for laboratory sensitivity and specificity • We think, however, that the 2005 estimates are more accurate than the 1999 estimates. • Future estimates will be even more accurate, IF we get better data.

  25. Added a Fifth Disease, Noncurable, Genital Herpes HSV-2) • An important STI • Relationship to HIV transmission

  26. Estimates of Prevalent Cases of HSV-2 Total=536 million Looker K et al. Bull WHO 2008;86:805-12

  27. Estimates of Incident Cases of HSV-2 Total=23.6 million Looker K et al. Bull WHO 2008;86:805-12

  28. Summary • For 2005, we estimate there were ~457,000,000 incident cases of chlamydia, gonorrhea, syphilis and trichomoniasis, and an additional 23.6 million cases of genital herpes • Incidence is probably higher than the 1999 estimates. This does not mean there has been a change since then—but we believe our estimates are more accurate • Approximately equal numbers of males and females were infected • There are surprisingly few well-conducted studies of infection in low- and middle-income countries

  29. Thank you!

  30. 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

  31. STI Syndromes (continued) • 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

  32. The Happy Young European

  33. Chancroid Gonorrhea Syphilis Infection increasingly asymptomatic Sex practices increasingly risky Chlamydia Genital herpes Trichomonas Human papillomavirus Glasier A et al. Lancet 2006;268:1-12

  34. 10% Risk

  35. 10% Risk 2% Risk 8% Risk 12% Risk 20% Risk

  36. STIs There are about 30 STIs or disease syndromes that result from STIs

  37. Prevalence of Antibody to HSV-2, Europe Smith J, Robinson J. J Infect Dis 2002; 186(S):S3

  38. Prevalence of Antibody to HSV-2 Sub-Saharan Africa Smith J, Robinson J. J Infect Dis 2002; 186(S):S3

  39. What is your time horizon?

  40. Time Line of Genital Herpes 5-7 days 7 days 7-21 days One year Inoculation First episode Recurrent episodes “Shedding” of virus

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