Syphilis Epidemiology

1
Syphilis Epidemiology

• Thad Zajdowicz, MD, MPH
• Medical Director, STD/HIV Program
• Chicago Dept of Public Health

2
(No Transcript)
3
Why a lecture on syphilis? Although
syphilis is an eminently treatable disease, its
continuing occurrence illustrates that our
control efforts still need to be improved. The
disease remains elusive clinically even today,
and unless thought of and sought for can silently
cause disease as it has for centuries. Further,
control of syphilis is vital because of its
interactions with HIV. This
lecture will focus on syphilis epidemiology
following lectures will explore the clinical
manifestations of this most protean of diseases.
4
Objectives

• To understand the prior and current impact of
  syphilis
• To define current trends of syphilis in the U.S.
• To understand how syphilis and HIV interact

5
Etiology and Course

• Syphilis is a chronic, systemic infection caused
  by a spirochete, Treponema pallidum. The primary
  mode of transmission is via sexual contact.
  Untreated, syphilis progresses through
  a primary and secondary stage before becoming
  latent. Up to 1/3 of people with untreated
  syphilis develop tertiary disease late in life,
  primarily cardiovascular and neurologic.
  Syphilis is also transmitted congenitally from an
  infected mother to her infant.

6
Historical Issues

• Emergence of syphilis in Europe in 1490s
• ? Imported from the Americas (Columbian theory)
  or ? Emergence in Europe from other
  treponematoses
• Severe disease (called The Great Pox to
  distinguish it from smallpox)

7
Pre-Penicillin Era

• Highly prevalent in many countries/societies in
  pre-penicillin era
• Estimates of 10 of U.S. population infected in
  early 20th Century
• Higher rates in socially disadvantaged
  populations, e.g. rural African-Americans in the
  South
• Dramatic drop in incidence/prevalence after
  introduction of penicillin in mid-1940s

8
Syphilis Worldwide

• WHO estimates 12 million new cases of syphilis
  worldwide (http//www.who.int/docstore/hiv/GRSTI/p
  df/figure09.pdf)
• Greatest burden in adolescents and young adults
• Greatest numbers of new cases in South and
  Southeast Asia, followed by sub-Saharan Africa

9
Syphilis in the U.S.
http//www.cdc.gov/std/stats/2002pdf/Syphilis.pdf
10
Current U.S. Syphilis Epidemiology

• Rates of primary and secondary (PS) syphilis
  declined every year from 1990-2000
• In 2001, rates of PS syphilis began rising again
• However, rise in new cases is seen in men who
  have sex with men (MSM)
• Malefemale ratio of cases rose from 11 to
  3.51 in past 8 years

11

Primary and Secondary Syphilis --- United States,
2002
12
PS Syphilis Cases by Region
Primary and Secondary Syphilis --- United States,
2002
13
Race Ethnicity

• In 2001-2002, PS syphilis rates increased 71.4
  among non-Hispanic white men and 28.6 among
  Hispanic men
• No changes in rates in females of same groups
• Among non-Hispanic blacks, PS syphilis rates
  decreased 10.9
• 2.2 for men, 22.6 for women
• There were significant rate changes in both
  Asian/Pacific Islanders and American
  Indians/Alaska Natives
• However, very few cases in both groups overall

14
PS Syphilis among MSM, Chicago, 2000-2002 by
Month of Treatment
CP
2000
2002
2001
15
PS Syphilis , by Gender and Sexual Orientation,
1998-2003, Chicago
N282
N292
N317
N353
N161
N338
16
Congenital Syphilis

• Syphilis is transmissible from mother to infant
• Transmission usually occurs during early stages,
  but may occur at any stage in an untreated mother
• Incidence of infection rose in U.S. in late
  1980s-early 1990s with rise in heterosexual cases

17
Congenital Syphilis

• Rates of congenital syphilis in U.S. continue to
  decline as new cases of PS syphilis decline in
  heterosexuals
• http//www.cdc.gov/std/stats/tablessyph.htm
• http//www.cdc.gov/epo/mmwr/preview/mmwrhtml/mm483
  4a3.htm

18
Epidemiological Synergy

• HIV and syphilis co-facilitate transmission of
  each other
• Biological plausible because
• STDs facilitate HIV shedding
• Cellular recruitment of HIV susceptible cells
  occurs
• Mucosal barriers are breached
• Immunosuppression

19
Behavioral Risk

• Behaviors that are risky for transmission of
  syphilis are also risky for transmission of HIV
• This has been demonstrated in studies in various
  areas of the world
• http//www.pubmedcentral.gov/articlerender.fcgi?to
  olgatewaypubmedid14585109

20
Sources of Information
The following sites are useful if more
information on syphilis epidemiology is
sought www.cdc.gov Centers for Disease
Control www.who.int World Health
Organization www.ashastd.org American Social
Hygiene Assoc www.vnh.org Virtual Naval Hospital