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National
Overview of Sexually Transmitted Diseases, 2000
The logo on the cover of Sexually Transmitted Disease Surveillance,
2000 is a reminder of the multifaceted, national dimensions
of the morbidity, mortality, and costs that result from sexually
transmitted diseases (STDs) in the United States. It highlights
the central role of STD prevention in improving health among
women and infants and in promoting HIV prevention. Organized
collaboration among interested, committed public and private
organizations is the key to reducing STDs and their related health
burdens in our population. As noted in the report of the Institute
of Medicine, The Hidden Epidemic: Confronting Sexually Transmitted
Diseases,1surveillance
is a key component of our efforts to prevent and control these
diseases.
This
overview summarizes national surveillance data on the three diseases
for which we have federally-funded control programs: chlamydia, gonorrhea,
and syphilis. Several observations for 2000 are worthy of note.
Chlamydia
In 2000, 702,093 cases of genital Chlamydia trachomatis infection
were reported to CDC (Table 1). This
case count corresponds to a rate of 257.5 cases per 100,000 persons,
an increase of 2.3% compared with the rate of 251.6 in 1999. Rates
of reported chlamydial infection among women have been increasing
annually since the late 1980s when public programs for screening
and treatment of women were first established to avert pelvic inflammatory
disease and related complications. Chlamydia screening and reporting
are likely to expand further in response to the recently implemented
Health Plan Employer Data and Information Set (HEDIS) measure for
chlamydia screening of sexually active women 15 to 25 years of
age who are provided medical care through managed care organizations.2 The
increase in chlamydia case reports in 2000 most likely represents
a continued increase in screening for this infection and also increased
use of more sensitive chlamydia screening tests than used in prior
years.
In
2000, the overall reported rate of chlamydial infection in the U.S.
among women (404.0 cases per 100,000 females) was approximately four
times the reported rate among men (102.8 cases per 100,000 males),
reflecting the large number of women screened for this disease. However,
with the increased availability of urine testing, men are increasingly
being tested for chlamydial infection. From 1996 to 2000, the reported
chlamydial infection rate in men increased by 71.9% (from 59.8 to
102.8 cases per 100,000 males) compared with a 26.4% increase in
women over this period (from 319.5 to 404.0 cases per 100,000 females),
reflecting increased screening among men (Tables 5 and 6) .
Data
from multiple sources on prevalence of chlamydial infection in defined
populations have been useful in monitoring disease burden and guiding
chlamydia screening programs. In 2000, the median state-specific
chlamydia test positivity among women 15 to 24 years who were screened
at selected family planning clinics in all states, the District of
Columbia, Puerto Rico, and the Virgin Islands was 5.2% (range, 2.3%
to 15.8%) (Figure
7), and at selected prenatal clinics in 23 states and Puerto
Rico, 5.9% (range, 2.2% to 14.5%) (Figure F). For economically-disadvantaged
women 16 to 24 years who entered the National Job Training Program
in 2000, from 30 states and Puerto Rico, the median state-specific
prevalence was 11.9% (range, 6.8% to 19.8%) (Figure
L). For women 15 to 30 years screened at Indian Health Service
(IHS) clinics in four IHS regions, the prevalence ranged from 3.9%
to 9.9% (Figure V).
For adolescent women entering juvenile detention centers in 24 U.S.
counties, the median chlamydia positivity was 15.0% (range, 1.5%
to 28.9%) (Figure
GG). For male entrants to the U.S. Army who were screened in
1999 and 2000, the overall chlamydia prevalence was 4.7% (range,
1.0% to 11.1% by state of residence) (Figure N). For adolescent men entering juvenile
detention centers in 30 counties, the median chlamydia positivity
was 6.6% (range, 0.9% to 13.0%) (Figure HH).
Although these data on prevalence are not entirely comparable because
of differences in the populations screened, in the performance characteristics
of the screening tests, and variations in screening criteria, they
provide important information on the continuing high burden of disease
in the United States.
In
parts of the United States where large scale chlamydia screening
programs have been instituted, prevalence of disease has declined
substantially. During 1988-2000, among 15-to 44-year-old women participating
in the screening programs in Health and Human Services (HHS) Region
X family planning clinics, chlamydia test positivity declined 59.2%
(from 13.0% to 5.3%) (Figure 8). After adjusting trends in chlamydia
positivity to account for changes in laboratory test methods and
associated increases in test sensitivity, chlamydia test positivity
decreased in four of 10 HHS regions from 1999 to 2000, and increased
in six regions. Although chlamydia positivity has declined in the
past year in some regions, most likely due to the effectiveness of
screening and treating women, continued expansion of screening programs
to populations with higher prevalence of disease may have contributed
to the increases in positivity seen in other regions. See the Appendix for
the composition of the HHS regions.
Gonorrhea
Following a 73.9% decline in the reported rate of gonorrhea
from 1975 (467.7) to 1997 (122.0), overall rates increased in 1998
(131.6) and have since remained essentially unchanged at the 1998
rate (Table 1). The
gonorrhea rate for 2000 (131.6 cases per 100,000 persons) remained
essentially unchanged from 1999 (132.0 cases per 100,000 persons)
and 1998 (131.6 per 100,000 persons) (Table 1). The 2000 rate for gonorrhea exceeds
the Healthy People 2010 (HP2010) objective of 19 cases per 100,000
persons.
The
gonorrhea rate in the U.S. among females in 2000 was similar to the
rate in 1999 (128.3 and 128.7 cases per 100,000 females, respectively)
(Table 14). Gender
differences in gonorrhea rates in 2000 (female rate 128.3 per 100,000,
male rate 134.6 per 100,000) were similar to the gender difference
in rates observed in 1999 (Tables 14 and 15). In contrast
to the 20 years prior to 1998, which generally exhibited decreasing
age-specific rates for gonorrhea, for most 5-year age categories
there was little change in the reported rates between 1999 and 2000.
As with chlamydia, rates of gonorrhea in women are particularly high
in 15- to 19-year-olds, and in men, are highest in the 20- to 24-year
age group.
In
2000, new data on gonorrhea prevalence in defined populations were
available from several sources. These new data showed continuing
high burden of disease in adolescents and young adults in some parts
of the United States. Among 15- to 24-year-old women attending selected
family planning clinics in 34 states and the Virgin Islands, the
median state-specific gonorrhea prevalence was 0.9 (range, 0.0 %
to 4.5%) (Figure 15).
For women in this age group attending selected prenatal clinics in
15 states, the median prevalence was 0.9% (range, 0.0% to 3.7%) (Figure G).
For 16- to 24-year-old women entering the National Job Training Program
in 21 states and Puerto Rico in 2000, the median gonorrhea prevalence
was 3.5% (range, 0.9% to 8.5%) (Figure
O). For adolescent women entering juvenile detention facilities,
the median positivity for gonorrhea was 4.9% (range, 0.5% to 13.0%)
(Figure II);
the median positivity in adolescent men entering juvenile detention
facilities was 2.4% (range, 0.6% to 4.2%) (Figure JJ).
Antimicrobial
resistance in Neisseria gonorrhoeae remains a continuing concern;
the most recent threat has been the increase in fluoroquinolone resistance
reported from several Asian countries. Ciprofloxacin is a fluoroquinolone
antibiotic that has been recommended for treatment of gonorrhea by
CDC; this oral medication is inexpensive and effectively treats gonorrhea
with a single dose. Although only 0.4% of N. gonorrhoeae isolates
tested through the Gonococcal Isolate Surveillance Project (GISP)
in 2000 demonstrated resistance to ciprofloxacin, this is a substantial
increase from 1998, when only 0.1% of isolates were reported to be
resistant. Of note, the proportion of GISP isolates from Honolulu
that were resistant to ciprofloxacin remains high and was 14.3% in
2000. This trend reinforces the recommendation made by CDC in 2000
that fluoroquinolones not be used to treat gonorrhea acquired in
Hawaii3.
In 2000, there was also a high proportion of GISP isolate resistant
to ciprofloxacin (5.6%) in Orange County, California. See Appendix for
a further description of GISP.
Data
on characteristics of patients in the GISP sample have been used
to obtain information on the sexual orientation of male STD clinic
patients with gonorrhea. In 2000, there was a continuing increase
in the proportion of GISP isolates from men who have sex with men
(MSM). In 2000, the proportion of GISP isolates from MSM increased
to 13.9% compared to 13.1% in 1999. In 1988 only 4.0% of isolates
were from MSM. The proportional increase in MSM in GISP has corresponded
to an absolute increase in gonorrhea cases among MSM at STD clinics
in several large cities that participate in GISP.
Syphilis
The National Plan to Eliminate Syphilis from the United States
was developed and announced by the Surgeon General in October 19994 in
response to several factors, including the important role of syphilis
in facilitating the transmission of HIV infection, the differential
impact of syphilis on racial and ethnic minorities, and the recent
decline in this disease. The 5,979 cases of primary and secondary
(P&S) syphilis reported in 2000 were the fewest cases ever
reported in the United States. However, the P&S syphilis rate
of 2.2 per 100,000 persons (the lowest since national reporting
began in 1941) remains substantially above the goal for syphilis
elimination of 0.4 case per 100,000 persons (about 1,000 cases
per year)4 (Table 1), and
the HP2010 goal of 0.2 per 100,000 persons.
The
number of P&S syphilis cases reported in 2000 was 9.6% lower
than the 6,617 cases reported in 1999. However, this decline was
substantially less than the reductions of approximately 20% per year
since the last major syphilis epidemic peaked in 1990. Although this
smaller decline may partially reflect improved case finding and reporting,
it also reflects the persistence of this disease in some populations
and recent outbreaks in several geographic areas, including outbreaks
among MSM.
One
factor that greatly facilitates syphilis elimination efforts is that
this disease continues to be primarily reported only in specific
areas of the country. In 2000, 2,520 (80.2%) of the 3,139 counties
in the United States reported no cases of P&S syphilis (see Appendix for
details on county coding). Half of all the P&S syphilis
cases were reported from only 21 counties and one city (0.7% of total
number of U.S. counties) (Table 24). However, the 2000 P&S syphilis
rates were greater than the HP2010 objective in 595 counties (18.9%
of the total number of U.S. counties). These 595 counties accounted
for more than 99.5% of all reported P&S syphilis cases (5,952
out of 5,979 cases). Sixty-nine percent (412 out of 595) of these
counties are located in the southern part of the United States. These
data suggest that comprehensive syphilis prevention efforts focused
in the South could markedly reduce the number of syphilis cases occurring
in the United States.
Between
1999 and 2000, the national rate of congenital syphilis decreased
by 7.6%, from 14.5 to 13.4 cases per 100,000 live births (Table 39). The
continuing reduction in congenital syphilis rates, occurring since
the early 1990s, reflects the substantial reduction in the rate of
P&S syphilis among women over the same period. In 2000, approximately
one half of the states and outlying areas had a reported rate of
congenital syphilis that was greater than the HP2010 objective of
1.0 case per 100,000 live births (Table 38).
Although
wide disparities exist in the reported rates of STDs among racial
and ethnic groups, there has been a reduction in these differences
for some diseases over the past five years. For example, the P&S
syphilis rate reported for 2000 among African-Americans was 21 times
the rate reported among whites, reflecting a substantial decline
from 1996, when the rate among African-Americans was 50 times greater
than that among whites (Table
32B). Although reporting biases likely magnify differences in
reported rates by race and ethnicity, these factors continue to be
risk markers among the U.S. population that correlate with other,
more fundamental determinants of health status such as socioeconomic
status and access to quality medical care.
Institute of Medicine. The Hidden Epidemic: Confronting Sexually Transmitted
Diseases, Committee on Prevention and Control of Sexually Transmitted
Diseases, National
Academy Press, Washington, DC, 1997.
National Committee for Quality Assurance
(NCQA). HEDIS 2000: Technical Specifications, Washington, DC, 1999, pp. 68-70, 285-286.
Centers for Disease Control and Prevention. Fluoroquinolone-resistance
in Neisseria gonorrhoeae, Hawaii, 1999, and decreased susceptibility
to azithromycin in N.
Gonorrhoeae, Missouri, 1999. MMWR 2000;49:833-837.
Division of STD Prevention. The National Plan to Eliminate Syphilis from the
United States. National Center
for HIV, STD, and TB Prevention, Centers for Disease Control
and Prevention, 1999.
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