CDC has been actively involved in disease-surveillance
activities since the formulation of the Communicable Disease
Center in 1946. The original scope of the National Surveillance
Program included the study of malaria, murine typhus, smallpox,
psittacosis, diphtheria, leprosy, and sylvatic plague. In 1954, a
surveillance section was established within the Epidemiology
Branch of CDC, primarily concerned with planning and conducting
continuing surveillance and making periodic reports. Occurrences
such as the Asian influenza pandemic and the discovery of
Legionnaires' disease prompted the involvement of CDC in
additional surveillance activities. Over the years the
surveillance activities of CDC have expanded to include not only
new areas in infectious disease but also programs in human
reproduction, injuries, environmental health, chronic disease,
risk reduction, and occupational safety and health. Ongoing
evaluation of these programs has led to new methods of data
collection and analysis and has prompted examination of how data
are disseminated to the public health community.
The publication titled CDC Surveillance Summaries was initiated
in 1982 after a survey was made of CDC staff and state
epidemiologists. Results of the survey suggested that improved
coordination of surveillance reports with the MMWR and the MMWR
Annual Summary (later titled Summary of Notifiable Diseases,
United States) would facilitate timely publication; provide
greater uniformity in the acquisition, evaluation, and reporting
of surveillance data; and encourage the use of these data.
In 1985, the CDC Surveillance Coordination Group was formed
with representatives from all Centers/Institute/Program Offices
and from the Council of State and Territorial Epidemiologists.
The Group was charged with developing and implementing a policy
for CDC's public health surveillance activities. State public
health officials also actively participate in the activities of
the Group. These activities, which are documented in regular
reports, are directed toward achieving the following goals: 1)
conducting epidemiologic surveillance of all health events
considered to be of high priority, 2) evaluating regularly all
CDC surveillance activities, 3) developing and evaluating
improved methods for the collection, analysis, and dissemination
of surveillance data, and 4) maintaining and improving the
expertise of CDC staff and constituents in the development,
implementation, and evaluation of systems of public health
surveillance.
Data Sources
Data on the reported occurrence of notifiable diseases are
derived from reports supplied by the state and territorial health
departments and by CDC program activities. These data are
published weekly in the MMWR, and the final official numbers of
cases are published in the annual Summary of Notifiable Diseases.
Complementary data are provided in MMWR surveillance summaries
and recommendations and reports. Data reported in the weekly MMWR
and the more detailed data reported by individual CDC programs
are collected independently; therefore, some numbers may be
slightly different because of the timing of reports or because of
refinements in case definition.
Data published in the MMWR series of publications should be
interpreted with caution. Some diseases that cause severe
clinical illness and are associated with serious consequences are
probably reported quite accurately; however, diseases that are
clinically mild and infrequently associated with serious
consequences are less likely to be reported. Additionally,
subclinical cases are seldom detected except in the course of
epidemic investigations or special studies. The degree of
completeness of reporting is also influenced by the diagnostic
facilities available, the control measures in effect, and the
interests and priorities of state and local officials responsible
for disease control and surveillance. Finally, factors such as
the introduction of new diagnostic tests and the discovery of new
disease entities may cause changes in disease reporting
independent of the true incidence of disease. Despite these
limitations, the data in these reports have proven to be very
useful in the analysis of trends.
Disclaimer
All MMWR HTML documents published before January 1993 are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.
**Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.
