The Scope Of Biosurveillance

The word biosurveillance is of recent origin.2 Biosurveillance overlaps with two existing terms: disease surveillance and public health surveillance. These terms are defined as systematic methods for the collection and analysis of data for the purpose of detecting disease (Thacker and Berkelman, 1988; Halperin and Baker, 1992;Teutsch and Churchill, 2000).

As with any new word, we could speculate whether its invention and growing usage signals the appearance of a new field or simply reflects an inadequacy of existing terminology.

1 Although it is difficult to identify components in federal and other government budgets that correspond to biosurveillance, as these organizations have broader missions, the overall 2005 budget of the Centers for Disease Control and Prevention (CDC) was $8 billion and the median budget for a state health department in 2004 was $2.9 billion (Hearne et al., 2004). The total U.S. government civilian biodefense funding for 2005 was estimated at $7.6 billion (Schuler, 2004), with $452 million allocated for agricultural laboratories, monitoring, and research and $129 million allocated for air monitoring (http://www.whitehouse.gov/ omb/pdf/Homeland-06.pdf ). A 1975 estimate of the cost of hospital infection control programs in the United States (updated to 2005 dollars) was $261 million (Haley, 1977).

2 In fact, the current edition of the Oxford English Dictionary (OED) does not define the word biosurveillance. although it is in widespread usage, as evinced by Google search results (13,000 hits on May 8, 2005) as well as its routine use by government agencies, politicians, journalists, and academics. There is no doubt that biosurveillance has been inducted into the common vernacular. Even those without technical expertise or training in the field understand the term intuitively, just as they understand the meaning of bioterrorism, another word currently left undefined in the OED. The absence of a standard definition reflects the need to synthesize the multidisciplinary work being done in the field. Indeed, this book is our effort to present a unified approach to and understanding of biosurveillance.

Handbook of Biosurveillance ISBN 0-12-369378-0

Elsevier Inc. All rights reserved.

FIGURE 1.1 The biosurveillance process. When the continuous collection and analysis of surveillance data raises suspicion of an outbreak or a single case of a dangerous disease, biosurveillance personnel must decide whether to react to the information. They may decide to collect additional data that feed back into the analytic process, resulting in better characterization of the event. They may decide to take actions such as the issuance of a boil-water advisory (in the case of suspected water contamination), closure of a restaurant, or treatment of individuals with antibiotics or vaccines. Whenever the staff (or an automatic system) decides to collect additional data, the biosurveillance process exhibits a feedback loop. If the event is confirmed, staff will make many decisions over time about additional data to collect, directed by the analysis of data accumulated to that point (a positive feedback loop).

FIGURE 1.1 The biosurveillance process. When the continuous collection and analysis of surveillance data raises suspicion of an outbreak or a single case of a dangerous disease, biosurveillance personnel must decide whether to react to the information. They may decide to collect additional data that feed back into the analytic process, resulting in better characterization of the event. They may decide to take actions such as the issuance of a boil-water advisory (in the case of suspected water contamination), closure of a restaurant, or treatment of individuals with antibiotics or vaccines. Whenever the staff (or an automatic system) decides to collect additional data, the biosurveillance process exhibits a feedback loop. If the event is confirmed, staff will make many decisions over time about additional data to collect, directed by the analysis of data accumulated to that point (a positive feedback loop).

Instead, we simply state why, after considerable deliberation, we selected the term biosurveillance for this book. The terms disease surveillance and public health surveillance connote disease surveillance practiced by governmental public health. Biosurveillance allows us to broaden the scope of our discussion to include many other organizations that monitor for disease, such as hospitals, agribusinesses, and zoos. These organizations share the same basic goals of identifying individuals (people or animals) with disease, understanding disease transmission patterns in a population, elucidating the root causes of disease outbreaks, and monitoring the microbiological status of the environment. They collect similar types of data (clinical, microbiological, and environmental), use similar techniques to analyze the data, and they all face difficult decisions regarding how to react to the data. They often interact with each other to achieve the goals of disease detection and characterization. The similarities in goals and techniques suggested that we should unify them conceptually.

We also decided against disease surveillance and public health surveillance because these terms, to an epidemiologist, connote surveillance for noninfectious disease, child mortality, injury, cigarette smoking, and dental diseases such as enamel fluorosis (CDC, 2005). To keep what was already a very large topic manageable, we decided against discussing surveillance for these conditions. The principles and techniques that we discuss, nevertheless, apply to surveillance for any disease or condition.

Importantly, we decided against disease surveillance and public health surveillance because we consider outbreak characterization (i.e., determining the organism, source, route of transmission, spatial distribution, and number of affected individuals) a key process in biosurveillance. Epidemiologists may not consider outbreak characterization as falling under disease surveillance or public health surveillance (e.g., Buehler, 1998: Chapter 22;Teutsch and Churchill, 2000). To an epidemiologist, the process of public health surveillance detects an outbreak, and then an investigation characterizes it. Biosurveillance, as we use the term, encompasses both detection and characterization.

As we will discuss later, processes that detect outbreaks also partially characterize them. Future advances in biosurveillance techniques will facilitate even better characterization of an outbreak at the time it is first detected. The blurring of the boundary between detection and characterization suggested that we should unify these processes conceptually.

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