1. Field of the Invention
This invention relates generally to biohazard surveillance systems and more particularly to an adaptive distributed system for the collection and sampling of hazardous particulates.
2. Description of the Related Art
The challenges we face from biological threat agents are increasing. While microbes continue to evolve and biotechnology becomes more powerful, the inherent hazards to humans, plants, and animals from infectious microorganisms are greatly increased by their intentional use by terrorists. The need for faster and better capabilities for warning, response, and cleanup was painfully evident in the case of a small-scale deployment of a noncontagious, naturally occurring anthrax pathogen. Terrorist use of other biological agents may result in far greater loss of life; agents that might be contagious or perhaps engineered for increased virulence and resistance to medical treatment. As microbes evolve and compete for survival, naturally emerging threats must also be quickly identified and distinguished from suspected terrorism. While the focus on bioterrorism is driven primarily by concerns about attacks on humans, attacks on livestock and/or crops can be just as devastating. A recent outbreak of foot-and-mouth disease in Great Britain demonstrates the devastating effect microbes can have on livestock and the consequent effect on food supply and economies. Rogue states have actively explored both animal and plant pathogens as weapons.
Lessons learned from the Persian Gulf War highlighted the need for biological warfare agent detectors and the subsequent solutions improved capability on the battlefield. However, other biological hazard (“biohazard”) surveillance deficiencies were soon recognized in the aftermath of conflict. “Gulf War Syndrome” and other ailments suffered by military personnel revealed a need for compact diagnostic tools with integrated sample-processing and detection capabilities to quickly identify disease-causing agents on and off the battlefield. In 1998, a consolidated approach was begun (at the Army Medical Institute for Infectious Diseases) to develop medical diagnostic systems using a common platform for biohazard identification entitled “The Common Diagnostic Systems for Biological Threats and Endemic Infectious Diseases.” Research encompassed development of rapid sample-processing methods, identification technologies, reagents and size reduction of laboratory analysis platforms.
In 2002, the Department of Defense (DoD) defined a new approach to a common medical test platform for identifying biological warfare agents and pathogens of operational concern. The Joint Biological Agent Identification and Diagnostic System (JBAIDS) exemplifies this approach. JBAIDS will be configured to support reliable, fast, and specific identification of biological agents from a variety of clinical specimens and environmental sources. JBAIDS will enhance force protection by providing commanders with information to determine actions to protect against and avoid contamination and to restore operations following an attack. JBAIDS information will aid medical personnel in determining appropriate treatment, effective preventive medical measures, and medical prophylaxis in response to the presence of biological agents. Required to combat the threat of biological attack faced by U.S. forces deployed worldwide, JBAIDS will also improve protection against endemic infectious diseases, thereby filling a need identified during the Persian Gulf War for a compact diagnostic identification tool. Today's global military mission, with ongoing operations in war-torn locations teeming with infectious diseases, demands a readily accessible, far-forward biological agent identification capability. This is critical to maintaining troop readiness, quickly determining patient treatment, disposition (for example, quarantine and medical evacuation), and protecting the homeland population from infections acquired by the military, from bioterrorism, and from emerging disease threats.
The DoD has addressed the biological threat in the context of the battlefield. However, biological threat reduction in the civilian population context is different. For example, the average civilian is not trained or equipped for response, the public health system is not supported with the kind of central command and control systems associated with the military, different requirements exist on sensitivity and different levels of tolerance for false positives and false negatives, and there is a need for dealing with a broader set of potential agents. Also, much higher sensitivity is required for Counter Terrorism (CT) detection, raising substantial technology challenges and the need to assess background interferences that may be more significant for low-level detection and monitoring schemes.
The urgent need for improved biohazard surveillance capability was also recognized and described for the first time in other Government agencies during this period. For example, the United States Postal Service has developed a Biohazard Detection System (BDS) using proven technology to implement early identification of anthrax. The BDS unit consists of an air-collection hood, a cabinet where the collection and analysis devices are housed, a local computer network connection, and a site controller (a networked computer). All BDS processes are automated. The equipment continuously collects air samples from mail canceling equipment while the canceling operation is underway. The air collection hood is installed over the canceling equipment at the very first pinch point in the mail processing operation where it absorbs and concentrates airborne particles into a sterile water base. This creates a liquid sample that is injected into a cartridge. An automated polymerase chain reaction (PCR) test is performed on the liquid sample using sophisticated DNA matching to detect the presence of anthrax (Bacillus anthracis). The test sample is compared to a template for the anthrax DNA sequence for a match. The system concentrates air samples for a one-hour period followed by the PCR test that takes approximately 30 minutes. The BDS is simultaneously concentrating particles for the next sample while the PCR test is performed for the previous sample. So while the first result requires approximately 1½ hours, subsequent results are obtained every hour. Upon detection of a DNA match, the BDS computer network conveys that information to the site controller computer. Local management is notified directly by on-site BDS personnel and also by multiple forms of electronic communication from the BDS site controller. The emergency action plan is activated, the facility's building alarm is sounded and everyone in the building is evacuated. Disadvantageously, the BDS is not adapted for identifying biohazards other than the anthrax spore.
Practitioners in the art have proposed various solutions to the sampling, detection, analysis, identification and reporting problems associated with the biohazard surveillance requirement. For example, in U.S. Pat. No. 5,895,922, Ho describes a process and apparatus for detection of viable and potentially hazardous biological particles that may be dispersed in an airstream. Ho teaches a method for directing each of the contained particles along a linear path through air, in a sequential manner, and sampling them for determination of their size, whether they are biological and viable, and whether they are present in concentrations greater than background levels. The particle size identifies the particles as respirable or not and the particles are characterized as biological and viable by subjecting each particle in turn, to 340 nm, ultraviolet laser light and looking for the emission of fluorescence, which is typically emitted from bacteria or bacterial spores. Fluorescence detected in the 400–540 nm range signals the presence of nicotinamide adenine dinucleotide hydrogen, which is indicative of biological activity or viability. Ho's apparatus is compact, and power-efficient because he uses a solid state, ultraviolet laser that is actuated only when the particle is passing the laser and only if it is deemed to be a biologically viable candidate, but it is disadvantageous for use in a remote automated surveillance station.
In U.S. Pat. No. 6,266,428, Flanigan discloses a system and method for remote detection of hazardous vapors and aerosols by means of two differential spectral signature spectra taken in the field of view at a low spectral resolution. A first linear discriminant optimized for the low spectral resolution is applied to the first spectrum to obtain a first response, and a hazardous cloud is detected automatically in accordance with the first response. A second differential spectral signature spectrum is taken in the field of view at a higher spectral resolution and a second linear discriminant optimized for the higher spectral resolution is applied to the second spectrum to obtain a second response, which is formed into a false-color image and displayed to an operator. The operator discriminates the hazardous cloud in accordance with the image. The first and second linear discriminants can be formed by linear programming. Flanigan's system is disadvantageous for use in a remote automated surveillance station.
In U.S. Pat. No. 6,317,080, Baxter discloses a method of tracking airborne substances including the steps of detecting the presence of one or more airborne substances and releasing a tracking balloon into the path of the one or more airborne substances, the tracking balloon having a transmission means and a global positioning means adapted to communicate the latitude and longitude coordinates of the tracking balloon whereby the latitude and longitude coordinates of the tracking balloon are representative of the latitude and longitude of the one or more airborne substances previously detected. Baxter neither considers nor suggests solutions to the remote automated surveillance problem.
In U.S. Pat. No. 6,490,530, Wyatt discloses an aerosol hazard classification and early warning network that includes a large number of remote detector and analysis units, which are deployed throughout a region under surveillance for a potentially hazardous aerosol intrusion. Such aerosol threats may originate from fires, volcanic eruptions, or overt releases of biological and chemical agents dispersed in aerosol form. Among the former are the characteristic toxic aerosols released during refinery fires or explosions. The latter biological agents include bacterial spores, lyophilized bacterial cells, and virus preparations, whereas chemical agents might include various forms of nerve gasses and other anti-personnel gasses such as mustard, all commonly deployed in aerosol form. Each detector station contains an aerosol handling unit that samples and transfers ambient aerosol particles one-at-a-time through a light scattering chamber where each such particle is constrained to pass through a fine laser beam producing, thereby, an outgoing scattered light wave. The scattering chamber contains a plurality of scattered light detectors arranged to accept light scattered into different angular locations. The signals detected at each detector position are processed by a corresponding digital signal processing chip with the resulting set of digitized signals being transferred to an on-board central processing unit (CPU). The CPU analyzes the set of light scattering signals and identifies or otherwise characterizes each particle. The classification data are then stored and, on preprogrammed command, telemetered to a remote “central station” by means of an on-board telemetry unit. The central station analyzes the sets of data received from all the detector stations and then instructs, as necessary, selected detector stations via telemetric means to change their sampling and telemetry rates. As soon as sufficient data are available, the central determines the presence, threat, extent, and progress of the aerosol cloud. These factors are then telemetrically transmitted by means of alarms and warnings sent to potentially threatened regions. Although Wyatt's system is well-adapted to remote surveillance and he teaches the use of fluorescence to identify biological compounds, his “light scattering” data are adapted to characterizing and counting particles in an aerosol and Wyatt doesn't consider the rapid and automated identification of biological particles.
In U.S. Pat. No. 6,532,067, Chang, et al. describe a method for fluorescence probing of particles flowing in a fluid, including steps of defining a trigger volume in the fluid by intersecting a plurality of substantially orthogonally aimed trigger laser beams, each of a different wavelength, detecting light scattered from the vicinity of the trigger volume by a plurality of particle detectors each sensitive to a wavelength corresponding to the wavelength of a trigger laser beam, probing the particles with a pulsed laser triggered by the particle detectors, collecting fluorescence emitted from the particle in a detection volume and focusing it in a detection region, detecting the fluorescence focused in the detection region. Chang, et al. neither consider nor suggest solutions to the remote automated surveillance problem.
In U.S. Pat. No. 6,613,571, Cordery et al. disclose a method and system for detecting biological and chemical hazards in mail using predetermined descriptions of the hazards sought but they neither consider nor suggest solutions to the remote automated surveillance problem. In U.S. Pat. No. 6,656,253, Willey, et al. disclose a dynamic electrostatic filter apparatus for purifying air using electrically charged liquid droplets but they neither consider nor suggest solutions to the remote automated surveillance problem. In U.S. Pat. No. 6,664,550, Rader et al. describe an aerosol lab-on-a-chip (ALOC) that integrates one or more of a variety of particle collection, classification, concentration (enrichment), an characterization processes onto a single substrate or layered stack of such substrates. By mounting a UV laser diode laser light source on the substrate, or substrates tack, so that it is located down-stream of the sample inlet port and at right angle the sample particle stream, the UV light source can illuminate individual particles in the stream to induce a fluorescence response in those particles having a fluorescent signature such as biological particles, some of said particles. An illuminated particle having a fluorescent signal above a threshold signal may trigger a sorter module that separates that particle from the particle stream. But Cordery et al. consider the process control and particle stream separation problems and neither consider nor suggest solutions to the remote automated surveillance problem.
In view of the recent terrorism-related security requirements mentioned above, there is a clearly-felt need in the art for a robust (military-hardened) miniaturized remote system for the initial detection, localized analysis and reporting of the presence of biohazards. Such a system requires a large number of permanently-deployed remote surveillance stations each of which can operate independently and without human intervention. Such stations must be adapted for accepting updated detection information from a remote control center to permit adaptation to global changes in the threat environment, for example.
These unresolved problems and deficiencies are clearly felt in the art and are solved by this invention in the manner described below.