An Example of Fragmentation in Disease Surveillance Systems

A recent study—based on a survey of public health officials in all 50 states, the District of Columbia, and New York City—of the Centers for Disease Control and Prevention's (CDC's) surveillance for food-borne illness notes that 20 different surveillance systems record information about food-borne illnesses and pathogens (GAO, 2001a). Of these, only four principal systems focus exclusively on food-borne illnesses and cover more than one pathogen:

1. The Foodborne Disease Outbreak Surveillance System (FDOSS) collects nationwide data about the incidence and causes of food-borne outbreaks. It relies on local health officials to take the initiative to report outbreaks to CDC through their state public health officials. CDC and others use this system mainly to maintain awareness of ongoing problems.

2. FoodNet actively collects information in nine geographic areas on nine specific food-borne pathogens, as well as on hemolytic-uremic syndrome (a complication of Escherichia coli O157:H7 infection), Guillain-Barre syndrome (a complication of Campylobacter infection), and toxoplasmosis. Public health officials who participate in FoodNet receive federal funds from CDC to systematically contact laboratories in their general area and solicit incidence data. This system provides more accurate estimates of the occurrence of food-borne diseases than are otherwise available.

3. PulseNet is used to identify whether separate cases of illness are likely to have originated from the same source. Using this system, public health officials can compare the new patterns to other patterns in the database; matches indicate an outbreak.

4. The Surveillance Outbreak Detection Algorithm (SODA) focuses on Salmonella and Shigella and uses statistical analyses to compare current data against a historical baseline to detect unusual increases in the incidence of these two pathogens. Increases may indicate an outbreak.

Although these four systems have contributed to improved food safety, the usefulness of the systems is marred both by the untimely release of the surveillance data and by gaps in the collected data. Twenty-six of the General Accounting Office survey respondents said that delays in publishing data from the FDOSS diminished the usefulness of the system. Many also said that rapid release of data from FoodNet, PulseNet, and SODA would make these systems more useful.

CDC attributed the delays in data dissemination to shortages in staffing. Additional staff have been hired since then, and they are training state and local health officials about the reporting needs of both state health departments and CDC (GAO, 2001a). However, CDC also noted that some of the delays in releasing information were due to the occasionally untimely reporting of surveillance data by state and local public health officials. Survey respondents said the problem is caused in part by shortages of trained epidemiologists in state and local health departments and by deficiencies in laboratory capabilities. Survey respondents also noted that the decisions regarding which diseases are tracked are made at the state level, which adds to the variability and incompleteness of the data when they are aggregated at the national level.


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