Go to full issue: DCN, July/August 2003: Volume 31, Number 5
Assessment is a core public health function, and surveillance for communicable diseases is one type of ongoing assessment activity. Epidemiologic surveillance is the systematic collection, analysis, and dissemination of health data for the planning, implementation, and evaluation of public health programs. The Minnesota Department of Health (MDH) collects disease surveillance information on certain communicable diseases for the purposes of determining disease impact, assessing trends in disease occurrence, characterizing affected populations, prioritizing disease control efforts, and evaluating disease prevention strategies. In addition, prompt surveillance reports allow outbreaks to be recognized in a timely fashion, when control measures are most likely to be effective in preventing additional cases.
In Minnesota, communicable disease reporting is a centralized system whereby reporting sources submit standardized report forms to MDH. These reports are monitored daily by disease-specific program staff. Cases of disease are reported pursuant to Minnesota Rules Governing Communicable Diseases (MN Rules 4605.7000 - 4605.7800). The Commissioner of Health has determined that the diseases listed in Table 1 must be reported to MDH. As stated in these rules, physicians, health care facilities, medical laboratories, veterinarians, and veterinary medical laboratories are required to report these diseases. Reporting sources may designate an individual within an institution to perform routine reporting duties (e.g., an infection control practitioner for a hospital). Data maintained by MDH are private and protected under the Minnesota Government Data Practices Act (Section 13.38). Provisions of the Health Insurance Portability and Accountability Act (HIPAA) allow for routine communicable disease reporting without patient authorization. For further discussion on HIPAA see the May 2003 issue of the Disease Control Newsletter (vol. 31, no. 3).
Since April 1995, MDH has participated as one of the Emerging Infections Program (EIP) sites funded by the Centers for Disease Control and Prevention (CDC) and, through this program, has implemented active hospital- and laboratory-based surveillance for several conditions, including selected invasive bacterial diseases and food-borne diseases.
Isolates for pathogens associated with certain diseases are required to be submitted to MDH (Table 1). The MDH Public Health Laboratory performs state-of-the-art microbiologic evaluation of isolates, such as pulsed-field gel electrophoresis (PFGE), to determine whether isolates of selected pathogens (e.g., enteric pathogens such as Salmonella and Escherichia coli O157:H7 and invasive pathogens such as Neisseria meningitidis) are related and, therefore, may be associated with a common source. In addition, testing of submitted isolates allows detection and monitoring of antimicrobial resistance, which continues to be an important problem with many pathogens.
Table 2 summarizes the numbers of cases of selected communicable diseases reported to MDH during 2002 by district of the patient's residence. Pertinent observations for some of these diseases are discussed below. A summary of influenza surveillance data also is included. However, these data do not appear in Table 2 because the influenza surveillance system is based on reported outbreaks rather than on individual cases. Influenza data reported here pertain to the 2002-2003 influenza season.
Incidence rates in this report were calculated using disease-specific numerator data collected by MDH and a standardized set of denominator data derived from U.S. Census data and used by the MDH Infectious Disease Epidemiology, Prevention, and Control Division for the purpose of maximizing the comparability of disease-specific morbidity and mortality rates reported by programs throughout the Division.