BIOSURVEILLANCE
symptoms of coughing up bloody sputum, that person is a ‘dead man walking’, with a systemic infection that is past the point of medical intervention.
Watching BioWatch Unfortunately, increasing sophistication and access to electronic data and analysis has not decreased criticisms of environmental pathogen biosurveillance systems such as BioWatch. Misidentifi cation errors with subsequent unnecessary public alarms have been widely publicised. Examples abound, including the September 2005 identifi cation of tularemia by six Department of Homeland Security (DHS) Biowatch sensors on the national mall in Washington, D.C., where local health offi cials were notifi ed of the event four to fi ve days later by the CDC, and not by the DHS, who owns and deploys the BioWatch detectors. More recently, additional false positive alerts received in 2010 by Maryland state health offi cials from Biowatch detectors that they were unaware had even been placed in their state by DHS! Interestingly, DHS does not consider these results to be ‘false positives’, as they claim that pathogen DNA was actually detected on those occasions, although no public health alerts were ever made as a result. Government offi cials have been understandably reluctant
to divest themselves of such a resource as BioWatch, due to their hope that it will provide a pre-disease onset detection capability in a population. However, the concerted eff orts to develop and improve upon disease detection may actually have decreased the time frame for pathogen detection by other population-based disease detection systems – notably from syndromic disease surveillance: that is, identifi cation of disease based upon its early symptom onset - to the point that perhaps one day this method may even supplant an environmental monitor such as BioWatch.
Syndromic signals The growth of syndromic disease surveillance presents a potential solution towards the need for a rapid response biosurveillance capability. Simply put, rather than wait for patients to exhibit full-blown symptoms required for clinical diagnosis, or for clinical laboratory confi rmation of a pathogen from clinical specimens - both of which could occur days aſt er an exposure to a biological agent - a syndromic surveillance
BIOWATCH Around $1 bn has been spent to date on
BioWatch, with a further $3 bn scheduled to be spent on system updates. It is therefore not surprising that continuing false positive alerts have caused some on the House
Homeland Security Committee to call for abandonment of this system. And, even if BioWatch worked fl awlessly, it might now
take as long as 36 hours for a true positive sample to initiate an alert.
system capitalizes on the earliest symptoms recordable following such an exposure. Many types of syndromic systems exist, including hospital-
based reporting, ambulance calls, pharmaceutical reporting, Internet-based data queries, and data mining. And if collected from a large group of individuals - such as might occur with a biological release at a mass gathering event – health offi cials could then act that much more rapidly, being notifi ed by means of a larger syndromic ‘signal’ about such an event.
BioSense and BioPHusion BioSense is an electronic public health information system that allows state health agencies and the CDC to quickly share information with each other such that the end-users have real-time information about any health condition anywhere in the country. BioPHusion is the CDC eff ort to incorporate all information available from multiple disparate data sources to provide a national and global public health situational awareness. It includes every data source mentioned in this article, along with myriad others, in the eff ort to provide our nation’s public health and political leaders with the best information available to understand and control disease outbreaks. So let’s now attempt to answer the question that we
started with – where are we with respect to attaining the best biosurveillance system possible? We’re a lot closer to getting there now than we were a decade ago. But, we certainly can’t rest on our laurels. We will need to continue to develop and integrate disease surveillance systems to alert us to the possibility of exposure to a deadly pathogen that can disrupt society. And we will somehow need to fi nd ways to transfer this technology to resource-poor countries – precisely those places from which a deadly pathogen such as a new pandemic infl uenza strain or SARS may initiate and/or spread. We’re getting there, but in the meantime, both Mother Nature and would-be bioterrorists are holding the countdown stopwatch, and they aren’t waiting for us to act! ❚❙
Col (Ret) Zygmunt F. Dembek PhD MS MPH is an epidemiologist and biochemist involved in response to disease outbreaks from public health disease surveillance systems including those using clinician, laboratory, and syndromic disease surveillance.
76 CBNW 2013/01
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