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Yuan L, Mikelonis AM, Yan E. Using SWMM for emergency response planning: A case study evaluating biological agent transport under various rainfall scenarios and urban surfaces. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131747. [PMID: 37454488 DOI: 10.1016/j.jhazmat.2023.131747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/11/2023] [Accepted: 05/29/2023] [Indexed: 07/18/2023]
Abstract
To assist in emergency preparedness for a biological agent terrorist attack or accidental pathogen release, potential contaminant levels and migration pathways of spores spread by urban stormwater were evaluated using a Storm Water Management Model (SWMM) of U.S. Coast Guard Base Elizabeth City, North Carolina. The high temporal-spatial resolution SWMM model was built using spore concentrations in stormwater runoff from asphalt, grass, and concrete collected from a point-scale field study. The subsequent modeled contamination scenarios included a notional plume release and point releases mimicking the field study under three rainfall conditions. The rainfall scenarios included a 6-hour natural rainfall event on Dec. 8, 2021 and two design storms (2-year and 100-year events). The observed spore concentrations from asphalt and concrete from the actual field experiment were applied to calibrate the washoff parameters in the SWMM model, using an exponential washoff function. The calibrated washoff coefficient (c1) and exponent (c2) were 0.01 and 1.00 for asphalt, 0.05 and 1.45 for grass, and 2.45 and 1.00 for concrete, respectively. The calibrated SWMM model simulated spore concentrations in runoff at times and magnitudes similar to the field study data. In the point release modeled scenario, the concrete surface generated 55.6% higher average spore concentrations than asphalt. Similarly, in the field experiment, a 175% (p < 0.05) higher average spore concentration in surface runoff was observed from concrete than from asphalt. This study demonstrates how SWMM may be used to evaluate spore washoff from urban surfaces under different precipitation amounts, intensities, and durations, and how visualized spatial migration pathways in stormwater runoff may be used for emergency planning and remediation.
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Affiliation(s)
- Lifeng Yuan
- US EPA Office of Research and Development, Center for Environmental Solutions and Emergency Response, Homeland Security Materials Management Division, Durham, NC, USA.
| | - Anne M Mikelonis
- US EPA Office of Research and Development, Center for Environmental Solutions and Emergency Response, Homeland Security Materials Management Division, Durham, NC, USA
| | - Eugene Yan
- Environmental Science Division of Argonne National Laboratory, Argonne, IL, USA
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Costantino V, Bahl P, Doolan C, de Silva C, Heslop D, Chen X, Lim S, MacIntyre CR. Modeling on the Effects of Deliberate Release of Aerosolized Inhalational Bacillus anthracis (Anthrax) on an Australian Population. Health Secur 2023; 21:61-69. [PMID: 36695665 DOI: 10.1089/hs.2022.0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
This study aimed to determine optimal mitigation strategies in the event of an aerosolized attack with Bacillus anthracis, a category A bioterrorism agent with a case fatality rate of nearly 100% if inhaled and untreated. To simulate the effect of an anthrax attack, we used a plume dispersion model for Sydney, Australia, accounting for weather conditions. We determined the radius of exposure in different sizes of attack scenarios by spore quantity released per second. Estimations of different spore concentrations were then used to calculate the exposed population to inform a Susceptible-Exposed-Infected-Recovered (SEIR) deterministic mathematical model. Results are shown as estimates of the total number of exposed and infected people, along with the burden of disease, to quantify the amount of vaccination and antibiotics doses needed for stockpiles. For the worst-case scenario, over 500,000 people could be exposed and over 300,000 infected. The number of deaths depends closely on timing to start postexposure prophylaxis. Vaccination used as a postexposure prophylaxis in conjunction with antibiotics is the most effective mitigation strategy to reduce deaths after an aerosolized attack and is more effective when the response starts early (2 days after release) and has high adherence, while it makes only a small difference when started late (after 10 days).
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Affiliation(s)
- Valentina Costantino
- Valentina Costantino, PhD, is a Postdoctoral Research Associate; in the Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Prateek Bahl
- Prateek Bahl, PhD, is a Postdoctoral Research Associate; at the School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - Con Doolan
- Con Doolan, PhD, is a Professor and Associate Dean (Academic Programs); at the School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - Charitha de Silva
- Charitha de Silva, PhD, is a Lecturer; at the School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia
| | - David Heslop
- David Heslop, PhD, MPH, is an Associate Professor, School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia
| | - Xin Chen
- Xin Chen, PhD, is a Postdoctoral Research Associate; in the Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Samsung Lim
- Samsung Lim, MA, PhD, is an Associate Professor, School of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia
| | - Chandini Raina MacIntyre
- Chandini Raina MacIntyre, MBBS, MAE, PhD, is a Professor and Head; in the Biosecurity Program, The Kirby Institute, University of New South Wales, Sydney, Australia.,Chandini Raina MacIntyre is also a Professor, College of Health Solutions and College of Public Service and Community Solutions, Arizona State University, Tempe, AZ
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Systematic Review and Evaluation of Mathematical Attack Models of Human Inhalational Anthrax for Supporting Public Health Decision Making and Response. Prehosp Disaster Med 2020; 35:412-419. [PMID: 32495728 DOI: 10.1017/s1049023x20000734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Anthrax is a potential biological weapon and can be used in an air-borne or mail attack, such as in the attack in the United States in 2001. Planning for such an event requires the best available science. Since large-scale experiments are not feasible, mathematical modelling is a crucial tool to inform planning. The aim of this study is to systematically review and evaluate the approaches to mathematical modelling of inhalational anthrax attack to support public health decision making and response. METHODS A systematic review of inhalational anthrax attack models was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The models were reviewed based on a set of defined criteria, including the inclusion of atmospheric dispersion component and capacity for real-time decision support. RESULTS Of 13 mathematical modelling studies of human inhalational anthrax attacks, there were six studies that took atmospheric dispersion of anthrax spores into account. Further, only two modelling studies had potential utility for real-time decision support, and only one model was validated using real data. CONCLUSION The limited modelling studies available use widely varying methods, assumptions, and data. Estimation of attack size using different models may be quite different, and is likely to be under-estimated by models which do not consider weather conditions. Validation with available data is crucial and may improve models. Further, there is a need for both complex models that can provide accurate atmospheric dispersion modelling, as well as for simpler modelling tools that provide real-time decision support for epidemic response.
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Dunbar J, Pillai S, Wunschel D, Dickens M, Morse SA, Franz D, Bartko A, Challacombe J, Persons T, Hughes MA, Blanke SR, Holland R, Hutchison J, Merkley ED, Campbell K, Branda CS, Sharma S, Lindler L, Anderson K, Hodge D. Perspective on Improving Environmental Monitoring of Biothreats. Front Bioeng Biotechnol 2018; 6:147. [PMID: 30406093 PMCID: PMC6207620 DOI: 10.3389/fbioe.2018.00147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/25/2018] [Indexed: 01/21/2023] Open
Abstract
For more than a decade, the United States has performed environmental monitoring by collecting and analyzing air samples for a handful of biological threat agents (BTAs) in order to detect a possible biological attack. This effort has faced numerous technical challenges including timeliness, sampling efficiency, sensitivity, specificity, and robustness. The cost of city-wide environmental monitoring using conventional technology has also been a challenge. A large group of scientists with expertise in bioterrorism defense met to assess the objectives and current efficacy of environmental monitoring and to identify operational and technological changes that could enhance its efficacy and cost-effectiveness, thus enhancing its value. The highest priority operational change that was identified was to abandon the current concept of city-wide environmental monitoring because the operational costs were too high and its value was compromised by low detection sensitivity and other environmental factors. Instead, it was suggested that the focus should primarily be on indoor monitoring and secondarily on special-event monitoring because objectives are tractable and these operational settings are aligned with likelihood and risk assessments. The highest priority technological change identified was the development of a reagent-less, real-time sensor that can identify a potential airborne release and trigger secondary tests of greater sensitivity and specificity for occasional samples of interest. This technological change could be transformative with the potential to greatly reduce operational costs and thereby create the opportunity to expand the scope and effectiveness of environmental monitoring.
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Affiliation(s)
- John Dunbar
- Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Segaran Pillai
- Food and Drug Administration, Washington, DC, United States
| | - David Wunschel
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Stephen A. Morse
- Centers for Disease Control and Prevention, Atlanta, GA, United States
- IHRC, Inc., Atlanta, GA, United States
| | | | - Andrew Bartko
- Battelle Memorial Institute, Columbus, OH, United States
| | | | - Timothy Persons
- Government Accountability Office, Washington, DC, United States
| | - Molly A. Hughes
- Government Accountability Office, Washington, DC, United States
| | | | | | - Janine Hutchison
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Eric D. Merkley
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | | | - Shashi Sharma
- Food and Drug Administration, Washington, DC, United States
| | - Luther Lindler
- Department of Homeland Security, Washington, DC, United States
| | - Kevin Anderson
- Department of Homeland Security, Washington, DC, United States
| | - David Hodge
- Department of Homeland Security, Washington, DC, United States
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Lioy PJ, Laskin JD, Georgopoulos PG. Preparedness and response to chemical and biological threats: the role of exposure science. Ann N Y Acad Sci 2016; 1378:108-117. [PMID: 27479653 PMCID: PMC5239671 DOI: 10.1111/nyas.13173] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/08/2016] [Accepted: 06/14/2016] [Indexed: 11/30/2022]
Abstract
There are multiple components to emergency preparedness and the response to chemical and biological threat agents. The 5Rs framework (rescue, reentry, recovery, restoration, and rehabitation) outlines opportunities to apply exposure science in emergency events. Exposure science provides guidance and refined tools for characterizing, assessing, and reducing risks from catastrophic events, such as the release of hazardous airborne chemicals or biological agents. Important challenges to be met include deployment of assets, including medications, before and after an emergency response situation. Assessment of past studies demonstrates the value of integrating exposure science methods into risk analysis and the management of catastrophic events.
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Affiliation(s)
- Paul J Lioy
- Environmental and Occupational Health Sciences Institute (EOHSI), Rutgers University, Piscataway, New Jersey
- Department of Environmental and Occupational Health, Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, New Jersey
| | - Jeffrey D Laskin
- Environmental and Occupational Health Sciences Institute (EOHSI), Rutgers University, Piscataway, New Jersey
- Department of Environmental and Occupational Health, Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, New Jersey
| | - Panos G Georgopoulos
- Environmental and Occupational Health Sciences Institute (EOHSI), Rutgers University, Piscataway, New Jersey.
- Department of Environmental and Occupational Health, Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, New Jersey.
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Katharios-Lanwermeyer S, Holty JE, Person M, Sejvar J, Haberling D, Tubbs H, Meaney-Delman D, Pillai SK, Hupert N, Bower WA, Hendricks K. Identifying Meningitis During an Anthrax Mass Casualty Incident: Systematic Review of Systemic Anthrax Since 1880. Clin Infect Dis 2016; 62:1537-1545. [PMID: 27025833 DOI: 10.1093/cid/ciw184] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/17/2016] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Bacillus anthracis, the causative agent of anthrax, is a potential bioterrorism agent. Anthrax meningitis is a common manifestation of B. anthracis infection, has high mortality, and requires more aggressive treatment than anthrax without meningitis. Its rapid identification and treatment are essential for successful management of an anthrax mass casualty incident. METHODS Three hundred six published reports from 1880 through 2013 met predefined inclusion criteria. We calculated descriptive statistics for abstracted cases and conducted multivariable regression on separate derivation and validation cohorts to identify clinical diagnostic and prognostic factors for anthrax meningitis. RESULTS One hundred thirty-two of 363 (36%) cases with systemic anthrax met anthrax meningitis criteria. Severe headache, altered mental status, meningeal signs, and other neurological signs at presentation independently predicted meningitis in the derivation cohort and were tested as a 4-item assessment tool for use during anthrax mass casualty incidents. Presence of any 1 factor on admission had a sensitivity for finding anthrax meningitis of 89% (83%) in the adult (pediatric) validation cohorts. Anthrax meningitis was unlikely in the absence of any of these signs or symptoms (likelihood ratio [LR]- = 0.12 [0.19] for adult [pediatric] cohorts), while presence of 2 or more made meningitis very likely (LR+ = 26.5 [30.0]). Survival of anthrax meningitis was predicted by treatment with a bactericidal agent (P = .005) and use of multiple antimicrobials (P = .01). CONCLUSIONS We developed an evidence-based assessment tool for screening patients for meningitis during an anthrax mass casualty incident. Its use could improve both patient outcomes and resource allocation in such an event.
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Affiliation(s)
- Stefan Katharios-Lanwermeyer
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jon-Erik Holty
- Pulmonary, Critical Care and Sleep Medicine Section, VA Palo Alto Healthcare System Department of Medicine, Stanford University, California
| | - Marissa Person
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - James Sejvar
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Dana Haberling
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Dana Meaney-Delman
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Nathaniel Hupert
- Departments of Healthcare Policy and Research and of Medicine, Weill Medical College, Cornell University, New York Presbyterian Hospital, New York
| | - William A Bower
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Katherine Hendricks
- Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia
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Van Leuken J, Swart A, Havelaar A, Van Pul A, Van der Hoek W, Heederik D. Atmospheric dispersion modelling of bioaerosols that are pathogenic to humans and livestock - A review to inform risk assessment studies. MICROBIAL RISK ANALYSIS 2016; 1:19-39. [PMID: 32289056 PMCID: PMC7104230 DOI: 10.1016/j.mran.2015.07.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/25/2015] [Accepted: 07/17/2015] [Indexed: 05/21/2023]
Abstract
In this review we discuss studies that applied atmospheric dispersion models (ADM) to bioaerosols that are pathogenic to humans and livestock in the context of risk assessment studies. Traditionally, ADMs have been developed to describe the atmospheric transport of chemical pollutants, radioactive matter, dust, and particulate matter. However, they have also enabled researchers to simulate bioaerosol dispersion. To inform risk assessment, the aims of this review were fourfold, namely (1) to describe the most important physical processes related to ADMs and pathogen transport, (2) to discuss studies that focused on the application of ADMs to pathogenic bioaerosols, (3) to discuss emission and inactivation rate parameterisations, and (4) to discuss methods for conversion of concentrations to infection probabilities (concerning quantitative microbial risk assessment). The studies included human, livestock, and industrial sources. Important factors for dispersion included wind speed, atmospheric stability, topographic effects, and deposition. Inactivation was mainly governed by humidity, temperature, and ultraviolet radiation. A majority of the reviewed studies, however, lacked quantitative analyses and application of full quantitative microbial risk assessments (QMRA). Qualitative conclusions based on geographical dispersion maps and threshold doses were encountered frequently. Thus, to improve risk assessment for future outbreaks and releases, we recommended determining well-quantified emission and inactivation rates and applying dosimetry and dose-response models to estimate infection probabilities in the population at risk.
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Affiliation(s)
- J.P.G. Van Leuken
- Centre for Infectious Disease Control (CIb), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Corresponding author: Centre for Infectious Disease Control, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, The Netherlands. Tel.: +31 30 274 2003.
| | - A.N. Swart
- Centre for Infectious Disease Control (CIb), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - A.H. Havelaar
- Centre for Infectious Disease Control (CIb), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Emerging Pathogens Institute and Animal Sciences Department, University of Florida, Gainesville, FL, United States of America
| | - A. Van Pul
- Environment & Safety (M&V), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - W. Van der Hoek
- Centre for Infectious Disease Control (CIb), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - D. Heederik
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Hamilton MA, Hong T, Casman E, Gurian PL. Risk-Based Decision Making for Reoccupation of Contaminated Areas Following a Wide-Area Anthrax Release. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2015; 35:1348-1363. [PMID: 25946233 DOI: 10.1111/risa.12383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This article presents an analysis of postattack response strategies to mitigate the risks of reoccupying contaminated areas following a release of Bacillus anthracis spores (the bacterium responsible for causing anthrax) in an urban setting. The analysis is based on a hypothetical attack scenario in which individuals are exposed to B. anthracis spores during an initial aerosol release and then placed on prophylactic antibiotics that successfully protect them against the initial aerosol exposure. The risk from reoccupying buildings contaminated with spores due to their reaerosolization and inhalation is then evaluated. The response options considered include: decontamination of the buildings, vaccination of individuals reoccupying the buildings, extended evacuation of individuals from the contaminated buildings, and combinations of these options. The study uses a decision tree to estimate the costs and benefits of alternative response strategies across a range of exposure risks. Results for best estimates of model inputs suggest that the most cost-effective response for high-risk scenarios (individual chance of infection exceeding 11%) consists of evacuation and building decontamination. For infection risks between 4% and 11%, the preferred option is to evacuate for a short period, vaccinate, and then reoccupy once the vaccine has taken effect. For risks between 0.003% and 4%, the preferred option is to vaccinate only. For risks below 0.003%, none of the mitigation actions have positive expected monetary benefits. A sensitivity analysis indicates that for high-infection-likelihood scenarios, vaccination is recommended in the case where decontamination efficacy is less than 99.99%.
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Affiliation(s)
- Michael A Hamilton
- Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Tao Hong
- ICF International, Durham, NC, USA
| | - Elizabeth Casman
- Department of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Patrick L Gurian
- Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA
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Evaluation of the relationship between the Adenosine Triphosphate (ATP) bioluminescence assay and the presence of Bacillus anthracis spores and vegetative cells. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:5708-19. [PMID: 24879485 PMCID: PMC4078544 DOI: 10.3390/ijerph110605708] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/15/2014] [Accepted: 05/20/2014] [Indexed: 11/17/2022]
Abstract
Background: The Adenosine triphosphate (ATP) bioluminescence assay was utilized in laboratory evaluations to determine the presence and concentration of vegetative and spore forms of Bacillus anthracis Sterne 34F2. Methods: Seventeen surfaces from the healthcare environment were selected for evaluation. Surfaces were inoculated with 50 µL of organism suspensions at three concentrations of 104, 106, 108 colony forming units per surface (CFU/surface) of B. anthracis. Culture-based methods and ATP based methods were utilized to determine concentrations. Results: When all concentrations were evaluated together, a positive correlation between log-adjusted CFU and Relative Light Units (RLU) for endospores and vegetative cells was established. When concentrations were evaluated separately, a significant correlation was not demonstrated. Conclusions: This study demonstrated a positive correlation for ATP and culture-based methods for the vegetative cells of B.anthracis. When evaluating the endospores and combining both metabolic states, the ATP measurements and CFU recovered did not correspond to the initial concentrations on the evaluated surfaces. The results of our study show that the low ATP signal which does not correlate well to the CFU results would not make the ATP measuring devises effective in confirming contamination residual from a bioterrorist event.
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Toth DJA, Gundlapalli AV, Schell WA, Bulmahn K, Walton TE, Woods CW, Coghill C, Gallegos F, Samore MH, Adler FR. Quantitative models of the dose-response and time course of inhalational anthrax in humans. PLoS Pathog 2013; 9:e1003555. [PMID: 24058320 PMCID: PMC3744436 DOI: 10.1371/journal.ppat.1003555] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 06/28/2013] [Indexed: 01/08/2023] Open
Abstract
Anthrax poses a community health risk due to accidental or intentional aerosol release. Reliable quantitative dose-response analyses are required to estimate the magnitude and timeline of potential consequences and the effect of public health intervention strategies under specific scenarios. Analyses of available data from exposures and infections of humans and non-human primates are often contradictory. We review existing quantitative inhalational anthrax dose-response models in light of criteria we propose for a model to be useful and defensible. To satisfy these criteria, we extend an existing mechanistic competing-risks model to create a novel Exposure–Infection–Symptomatic illness–Death (EISD) model and use experimental non-human primate data and human epidemiological data to optimize parameter values. The best fit to these data leads to estimates of a dose leading to infection in 50% of susceptible humans (ID50) of 11,000 spores (95% confidence interval 7,200–17,000), ID10 of 1,700 (1,100–2,600), and ID1 of 160 (100–250). These estimates suggest that use of a threshold to human infection of 600 spores (as suggested in the literature) underestimates the infectivity of low doses, while an existing estimate of a 1% infection rate for a single spore overestimates low dose infectivity. We estimate the median time from exposure to onset of symptoms (incubation period) among untreated cases to be 9.9 days (7.7–13.1) for exposure to ID50, 11.8 days (9.5–15.0) for ID10, and 12.1 days (9.9–15.3) for ID1. Our model is the first to provide incubation period estimates that are independently consistent with data from the largest known human outbreak. This model refines previous estimates of the distribution of early onset cases after a release and provides support for the recommended 60-day course of prophylactic antibiotic treatment for individuals exposed to low doses. Anthrax poses a potential community health risk due to accidental or intentional aerosol release. We address the need for a transparent and defensible quantitative dose-response model for inhalational anthrax that is useful for risk assessors in estimating the magnitude and timeline of potential public health consequences should a release occur. Our synthesis of relevant data and previous modeling efforts identifies areas of improvement among many commonly cited dose-response models and estimates. To address those deficiencies, we provide a new model that is based on clear, transparent assumptions and published data from human and non-human primate exposures. Our resulting estimates provide important insight into the infectivity to humans of low inhaled doses of anthrax spores and the timeline of infections after an exposure event. These insights are critical to assessment of the impacts of delays in responding to a large scale aerosol release, as well as the recommended course of antibiotic administration to those potentially exposed.
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Affiliation(s)
- Damon J. A. Toth
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
- Department of Mathematics, University of Utah, Salt Lake City, Utah, United States of America
- VA Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
- * E-mail: (DJAT); (AVG)
| | - Adi V. Gundlapalli
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
- VA Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
- Department of Pathology, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Informatics, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail: (DJAT); (AVG)
| | - Wiley A. Schell
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, North Carolina, United States of America
| | - Kenneth Bulmahn
- Independent Risk Assessment Contractor, Idaho Falls, Idaho, United States of America
| | - Thomas E. Walton
- Centers for Epidemiology and Animal Health, United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, Colorado, United States of America
| | - Christopher W. Woods
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, North Carolina, United States of America
| | - Catherine Coghill
- Independent Risk Assessment Contractor, Santa Fe, New Mexico, United States of America
| | - Frank Gallegos
- Independent Risk Assessment Contractor, Santa Fe, New Mexico, United States of America
| | - Matthew H. Samore
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
- VA Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
- Department of Biomedical Informatics, University of Utah, Salt Lake City, Utah, United States of America
| | - Frederick R. Adler
- Department of Mathematics, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
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Georgopoulos PG, Isukapalli SS. A unified multiscale field/network/agent based modeling framework for human and ecological health risk analysis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:6420-3. [PMID: 19964423 DOI: 10.1109/iembs.2009.5333795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A conceptual framework is presented for multi-scale field/network/agent-based modeling to support human and ecological health risk assessments. This framework is based on the representation of environmental dynamics in terms of interacting networks, agents that move across different networks, fields representing spatiotemporal distributions of physical properties, rules governing constraints and interactions, and actors that make decisions affecting the state of the system. Different deterministic and stochastic modeling case studies focusing on environmental exposures and associated risks are provided as examples, utilizing the bidirectional mapping between discrete, agent based approaches and continuous, equation based approaches. These examples include problems describing human health risk assessment, ecological risk assessment, and environmentally caused disease.
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Affiliation(s)
- Panos G Georgopoulos
- Environmental and Occupational Health Sciences Institute, a Joint Institute of UMDNJ-RW Johnson Medical School and Rutgers University, Piscataway, NJ 08854, USA.
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Cohen Hubal EA, Richard A, Aylward L, Edwards S, Gallagher J, Goldsmith MR, Isukapalli S, Tornero-Velez R, Weber E, Kavlock R. Advancing exposure characterization for chemical evaluation and risk assessment. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2010; 13:299-313. [PMID: 20574904 DOI: 10.1080/10937404.2010.483947] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A new generation of scientific tools has emerged to rapidly measure signals from cells, tissues, and organisms following exposure to chemicals. High-visibility efforts to apply these tools for efficient toxicity testing raise important research questions in exposure science. As vast quantities of data from high-throughput screening (HTS) in vitro toxicity assays become available, this new toxicity information must be translated to assess potential risks to human health from environmental exposures. Exposure information is required to link information on potential toxicity of environmental contaminants to real-world health outcomes. In the immediate term, tools are required to characterize and classify thousands of environmental chemicals in a rapid and efficient manner to prioritize testing and assess potential for risk to human health. Rapid risk assessment requires prioritization based on both hazard and exposure dimensions of the problem. To address these immediate needs within the context of longer term objectives for chemical evaluation and risk management, a translation framework is presented for incorporating toxicity and exposure information to inform public health decisions at both the individual and population levels. Examples of required exposure science contributions are presented with a focus on early advances in tools for modeling important links across the source-to-outcome paradigm. ExpoCast, a new U.S. Environmental Protection Agency (EPA) program aimed at developing novel approaches and metrics to screen and evaluate chemicals based on the potential for biologically relevant human exposures is introduced. The goal of ExpoCast is to advance characterization of exposure required to translate findings in computational toxicology to information that can be directly used to support exposure and risk assessment for decision making and improved public health.
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Affiliation(s)
- Elaine A Cohen Hubal
- National Center for Computational Toxicology, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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Georgopoulos PG, Sasso AF, Isukapalli SS, Lioy PJ, Vallero DA, Okino M, Reiter L. Reconstructing population exposures to environmental chemicals from biomarkers: challenges and opportunities. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2009; 19:149-71. [PMID: 18368010 PMCID: PMC3068528 DOI: 10.1038/jes.2008.9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 01/22/2008] [Indexed: 05/20/2023]
Abstract
A conceptual/computational framework for exposure reconstruction from biomarker data combined with auxiliary exposure-related data is presented, evaluated with example applications, and examined in the context of future needs and opportunities. This framework employs physiologically based toxicokinetic (PBTK) modeling in conjunction with numerical "inversion" techniques. To quantify the value of different types of exposure data "accompanying" biomarker data, a study was conducted focusing on reconstructing exposures to chlorpyrifos, from measurements of its metabolite levels in urine. The study employed biomarker data as well as supporting exposure-related information from the National Human Exposure Assessment Survey (NHEXAS), Maryland, while the MENTOR-3P system (Modeling ENvironment for TOtal Risk with Physiologically based Pharmacokinetic modeling for Populations) was used for PBTK modeling. Recently proposed, simple numerical reconstruction methods were applied in this study, in conjunction with PBTK models. Two types of reconstructions were studied using (a) just the available biomarker and supporting exposure data and (b) synthetic data developed via augmenting available observations. Reconstruction using only available data resulted in a wide range of variation in estimated exposures. Reconstruction using synthetic data facilitated evaluation of numerical inversion methods and characterization of the value of additional information, such as study-specific data that can be collected in conjunction with the biomarker data. Although the NHEXAS data set provides a significant amount of supporting exposure-related information, especially when compared to national studies such as the National Health and Nutrition Examination Survey (NHANES), this information is still not adequate for detailed reconstruction of exposures under several conditions, as demonstrated here. The analysis presented here provides a starting point for introducing improved designs for future biomonitoring studies, from the perspective of exposure reconstruction; identifies specific limitations in existing exposure reconstruction methods that can be applied to population biomarker data; and suggests potential approaches for addressing exposure reconstruction from such data.
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Affiliation(s)
- Panos G Georgopoulos
- Environmental and Occupational Health Sciences Institute (EOHSI), a joint institute of UMDNJ-RW Johnson Medical School & Rutgers University, Piscataway, NJ 08854, USA.
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Georgopoulos PG, Sasso AF, Isukapalli SS, Lioy PJ, Vallero DA, Okino M, Reiter L. Reconstructing population exposures to environmental chemicals from biomarkers: challenges and opportunities. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2009; 19:149-171. [PMID: 18368010 DOI: 10.1m038/jes.2008.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A conceptual/computational framework for exposure reconstruction from biomarker data combined with auxiliary exposure-related data is presented, evaluated with example applications, and examined in the context of future needs and opportunities. This framework employs physiologically based toxicokinetic (PBTK) modeling in conjunction with numerical "inversion" techniques. To quantify the value of different types of exposure data "accompanying" biomarker data, a study was conducted focusing on reconstructing exposures to chlorpyrifos, from measurements of its metabolite levels in urine. The study employed biomarker data as well as supporting exposure-related information from the National Human Exposure Assessment Survey (NHEXAS), Maryland, while the MENTOR-3P system (Modeling ENvironment for TOtal Risk with Physiologically based Pharmacokinetic modeling for Populations) was used for PBTK modeling. Recently proposed, simple numerical reconstruction methods were applied in this study, in conjunction with PBTK models. Two types of reconstructions were studied using (a) just the available biomarker and supporting exposure data and (b) synthetic data developed via augmenting available observations. Reconstruction using only available data resulted in a wide range of variation in estimated exposures. Reconstruction using synthetic data facilitated evaluation of numerical inversion methods and characterization of the value of additional information, such as study-specific data that can be collected in conjunction with the biomarker data. Although the NHEXAS data set provides a significant amount of supporting exposure-related information, especially when compared to national studies such as the National Health and Nutrition Examination Survey (NHANES), this information is still not adequate for detailed reconstruction of exposures under several conditions, as demonstrated here. The analysis presented here provides a starting point for introducing improved designs for future biomonitoring studies, from the perspective of exposure reconstruction; identifies specific limitations in existing exposure reconstruction methods that can be applied to population biomarker data; and suggests potential approaches for addressing exposure reconstruction from such data.
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Affiliation(s)
- Panos G Georgopoulos
- Environmental and Occupational Health Sciences Institute (EOHSI), a joint institute of UMDNJ-RW Johnson Medical School & Rutgers University, Piscataway, NJ 08854, USA.
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