Sexually Transmitted Disease Surveillance 1996

Division of STD Prevention September 1997

U.S. Department of Health and Human Services 
Public Health Service 
Centers for Disease Control and Prevention  
National Center for HIV, STD, and TB Prevention 
Division of STD Prevention 
Atlanta, Georgia 30333

Copyright Information 

All material contained in this report is in the public domain and may be
used and reprinted without special permission; citation to source, however,
is appreciated.

Suggested Citation

Division of STD Prevention. Sexually Transmitted Disease Surveillance,
1996. U.S. Department of Health and Human Services, Public Health Service.
Atlanta: Centers for Disease Control and Prevention, September 1997.

Copies can be obtained from the Office of Communications, National Center
for HIV, STD, and TB Prevention, Centers for Disease Control and
Prevention, 1600 Clifton Road, Mailstop E-06, Atlanta, Georgia 30333.

The reports for 1993 through 1996 are available electronically on CDC
WONDER. For information about registering for CDC WONDER, please contact
CDC's Epidemiology Program Office at (888) 496-8347. These reports are also
available from the Internet via the CDC home page address
http://wonder.cdc.gov/wonder/data/Reports.html. 


Chlamydia

Infections due to Chlamydia trachomatis are among the most prevalent of all
sexually transmitted diseases. In women these infections often result in
pelvic inflammatory disease, which can cause infertility, ectopic
pregnancy, and chronic pelvic pain. Data from a randomized controlled trial
of chlamydia screening in a managed care setting suggest that such
screening programs can reduce the incidence of PID by as much as 60% (1).
In addition, pregnant women infected with chlamydia can infect their babies
during delivery.

While case reporting of chlamydial infections is improving, it remains
incomplete in many areas of the country. A combination of factors limit the
documentation of the incidence and prevalence of genital chlamydial
infection: variable compliance with public health laws and regulations that
require health care providers and laboratories to report cases to local
health authorities; large numbers of asymptomatic persons who can be
identified only through screening; limited resources to support screening
activities; and incompletely developed information management systems for
collecting, maintaining, and analyzing case reporting and prevalence data.
Thus, for most areas, the number of chlamydia cases reported to CDC by
state health departments reflects many factors, only one of which is number
of infections in the population. For defined populations of sexually active
women, data on prevalence obtained through routine screening can provide a
more accurate measure of the true burden of disease. 

--  In 1996, 49 states and the District of Columbia required reporting of
    chlamydia and reported cases to CDC. Only cases from New York City were
    reported for the state of New York (Figure_1, Table_5).

--  In 1996, 490,080 chlamydial infections were reported to CDC from 49
    states, District of Columbia and New York City (Table_1). Reported
    cases of chlamydia far exceed reported cases of gonorrhea (325,883
    gonorrhea cases in 1996, Table_1).

--  From 1987 through 1996 reported rates of chlamydia increased from 47.8
    cases per 100,000 persons to 194.5 (Figure_2). This trend reflects
    increased screening, recognition of asymptomatic infection (mainly in
    women), and improved reporting, as well as the continuing high burden
    of disease.

--  In 1996, the chlamydia case rate was highest in the South, reflecting a
    recent expansion of screening activity in this Region. Before 1996,
    reported chlamydia rates were highest in the West and Midwest, where
    substantial resources had been committed for screening programs (e.g.,
    in family planning clinics) (Table_5, Figure_3 and
    Figure_4).

--  Between 1995 and 1996, rates of chlamydia reported from selected large
    cities (>200,000 population) increased 2% from 313.2 cases per 100,000
    persons to 318.6 (Figure_5, Table_9).

--  Reported rates of chlamydia for women (321.5 per 100,000 persons)
    exceed those for men (60.4) (Figure_6, Table_6, Table_7,
    Table_10, and Table_11). This is mainly due to detection of
    asymptomatic infection in women through screening. The low rates in men
    suggest that many of the sex partners of women with chlamydia are not
    diagnosed or reported. In addition, men diagnosed as having
    non-gonococcal urethritis are treated but frequently not tested. A
    large proportion of these men are infected with chlamydia, but they are
    not detected by surveillance systems based on laboratory reporting of
    positive chlamydia tests.

--  Rates of chlamydia for women are highest in the 15- to 19- year-olds
    (2,068.6 per 100,000) and in the 20- to 24-year-olds (1,485.2). For
    men, age-specific rates are also highest in these age groups
    (Figure_7, Table_3B).

--  Chlamydia screening and prevalence-monitoring activities were initiated
    in Health and Human Services (HHS) Region X in 1988 as a CDC-supported
    demonstration project. In 1993, chlamydia screening services for women
    were initiated in three additional HHS regions (III, VII, and VIII)
    and, in 1995, in the remaining HHS regions (I, II, IV, V, VI, and IX).
    In some regions, federally-funded chlamydia screening supplements
    local- and state-funded screening programs.

--  In 1996, state-specific chlamydia test positivity among 15- to 24-year- 
    old women screened varied from 2.5% to 10.9% among those attending
    family planning clinics (Figure_9). These chlamydia test positivity
    rates are from those states reporting data on 1,000 or more women
    screened during 1996.

--  The effectiveness of large-scale screening programs in reducing
    chlamydia prevalence in women has been well documented in areas where
    this intervention has been in place for several years. For example, the
    screening programs in Health and Human Services Region X (Alaska,
    Idaho, Oregon, Washington) family planning clinics have demonstrated a
    decline in chlamydia positivity of 61% since 1988 among 15- to 44-year- 
    old women. Introduction of large-scale screening in HHS Region III and
    HHS Region VIII has also been followed by similar declines in chlamydia
    positivity (Figure_10).

--  Additional information on chlamydia screening programs for women of
    reproductive age and chlamydia among adolescents and minority
    populations can be found in the Special Focus Profiles section.

Figure_1.   Chlamydia -- Number of states that require reporting of
                Chlamydia trachomatis infections: United States, 1987-1996
Figure_2.   Chlamydia -- Reported rates: United States, 1984-1996
Figure_3.   Chlamydia -- Rates by state: United States and outlying
                areas, 1996
Figure_4.   Chlamydia -- Rates by region: United States, 1984-1996
Figure_5.   Chlamydia -- Rates in selected U.S. cities of >200,000
                population, 1984-1996
Figure_6.   Chlamydia -- Rates by gender: United States, 1984-1996
Figure_7.   Chlamydia -- Age- and gender-specific rates: United States, 
                1996
Figure_8.   Chlamydia -- Percent positivity among women tested in 
                family planning clinics by state: Region X, 1988-1996
Figure_9.   Chlamydia -- Percent positivity among 15-24 year old women 
                tested in selected family planning clinics by state, 1996
Figure_10.  Chlamydia -- Percent positivity among 15-44 year old women
                tested in family planning clinics by HHS regions: 1996

----------
(1) Scholes D, Stergachis A, Heidrich FE, Andrilla H, Holmes KK, Stamm WE.
    Prevention of pelvic inflammatory disease by screening for cervical
    chlamydial infection. N Engl J Med  1996;34(21):1362-66.

---