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Galante D, Gainer RS, Hugh-Jones ME. Environmental relationships and anthrax epidemiology: field experiences of host resistance as opposed to dose-dependent experiments. Acta Trop 2024; 252:107128. [PMID: 38309609 DOI: 10.1016/j.actatropica.2024.107128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/10/2024] [Accepted: 01/21/2024] [Indexed: 02/05/2024]
Abstract
Even though anthrax is a disease of antiquity that has been studied for centuries, serious concerns have been raised about our understanding of its epidemiology. Since the 1960s, we have based the epidemiology of anthrax on the results of dose-dependent experiments, especially those involving cattle at that time. In this species the experiments demonstrated that the severity of infection was dependent upon the numbers of Bacillus anthracis spores ingested. The opinion was that ingesting only a few spores would be insufficient to cause an apparent infection; any infection that resulted would be latent (i.e., unrecognized). Based on the results of these experiments, it was accepted that the ingestion of large numbers of spores was the source of infection for hundreds of anthrax outbreaks. However, many investigations of both human and animal anthrax outbreaks have failed to identify sources of large numbers of spores, suggesting that these outbreaks are only rarely a consequence of ingestion or inhalation of large quantities of spores. This opinion piece builds upon the indirect evidence previously presented in an article focused on the existence of latent infections. Much of the evidence for the existence of latent infections was predicated upon a reduction of host resistance, which revealed how latent infections could be a source of more severe forms of the infection. That is, a latent infection can be the source of a severe infection, but the cause of the severe infection is the reduced host resistance. That first article concentrated on the arguments for latent infections, while this article concentrates on the arguments for host resistance. Host resistance is virtually impossible to measure objectively in the field. To provide a subjective measure of host resistance during anthrax outbreaks, we suggest the use of the opinions of livestock owners and or their veterinary practitioners and or field workers during investigations of anthrax outbreaks. When veterinary personal work in the field they are much like field biologists. In some ways field biologists better appreciate environmental factors, population ecology and other perspectives that are of use to epidemiologists. The more diverse the information the better the epidemiology is understood. To this effect we present our personal anecdotal and theoretical ideas from our experiences as well as a collection of bibliographic observations from others'. Our conclusions are that a combination of latent infections and reduced host resistance based on the host's relationship with its environment would better explain the epidemiology of severe infections in anthrax outbreaks for which large quantities of spores have not been located. This applies especially if the area has a history of the disease and/or if necropsies have shown the presence of latent infections in otherwise normal animals in the area and/or if environmental conditions are considered stressful and include intense insect activity.
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Affiliation(s)
- Domenico Galante
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Anthrax Reference Institute of Italy, Via Manfredonia 20, 71121, Foggia, Italy.
| | | | - Martin E Hugh-Jones
- Department of Environmental Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803-5705, USA
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2
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Temrikar ZH, Golden JE, Jonsson CB, Meibohm B. Clinical and Translational Pharmacology Considerations for Anti-infectives Approved Under the FDA Animal Rule. Clin Pharmacokinet 2023; 62:943-953. [PMID: 37326917 PMCID: PMC10471120 DOI: 10.1007/s40262-023-01267-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2023] [Indexed: 06/17/2023]
Abstract
The US Food and Drug Administration's Animal Rule provides a pathway for approval of drugs and biologics aimed to treat serious or life-threatening conditions wherein traditional clinical trials are either not ethical or feasible. In such a scenario, determination of safety and efficacy are based on integration of data on drug disposition and drug action collected from in vitro models, infected animals, and healthy volunteer human studies. The demonstration of clinical efficacy and safety in humans based on robust, well-controlled animal studies is filled with challenges. This review elaborates on the challenges in the translation of data from in vitro and animal models to human dosing for antimicrobials. In this context, it discusses precedents of drugs approved under the Animal Rule, along with the approaches and guidance undertaken by sponsors.
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Affiliation(s)
- Zaid H Temrikar
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN, 38163, USA
| | - Jennifer E Golden
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI, USA
| | - Colleen B Jonsson
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN, 38163, USA
- Department of Microbiology, Immunology, Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
- Regional Biocontainment Laboratory, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bernd Meibohm
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN, 38163, USA.
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3
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Sittner A, Ben-Shmuel A, Glinert I, Bar-David E, Schlomovitz J, Kobiler D, Weiss S, Levy H. Using old antibiotics to treat ancient bacterium-β-lactams for Bacillus anthracis meningitis. PLoS One 2020; 15:e0228917. [PMID: 32053632 PMCID: PMC7018077 DOI: 10.1371/journal.pone.0228917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/23/2020] [Indexed: 11/19/2022] Open
Abstract
As Bacillus anthracis spores pose a proven bio-terror risk, the treatment focus has shifted from exposed populations to anthrax patients and the need for effective antibiotic treatment protocols increases. The CDC recommends carbapenems and Linezolid (oxazolidinone), for the treatment of anthrax, particularly for the late, meningeal stages of the disease. Previously we demonstrated that treatment with Meropenem or Linezolid, either as a single treatment or in combination with Ciprofloxacin, fails to protect rabbits from anthrax-meningitis. In addition, we showed that the failure of Meropenem was due to slow BBB penetration rather than low antibacterial activity. Herein, we tested the effect of increasing the dose of the antibiotic on treatment efficacy. We found that for full protection (88% cure rate) the dose should be increased four-fold from 40 mg/kg to 150 mg/kg. In addition, B. anthracis is a genetically stable bacterium and naturally occurring multidrug resistant B. anthracis strains have not been reported. In this manuscript, we report the efficacy of classical β-lactams as a single treatment or in combination with β-lactamase inhibitors in treating anthrax meningitis. We demonstrate that Ampicillin based treatment of anthrax meningitis is largely efficient (66%). The high efficacy (88-100%) of Augmentin (Amoxicillin and Clavulonic acid) and Unasyn (Ampicillin and Sulbactam) makes them a favorable choice due to reports of β-lactam resistant B. anthracis strains. Tazocin (Piperacillin and Tazobactam) proved inefficient compared to the highly efficient Augmentin and Unasyn.
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Affiliation(s)
- Assa Sittner
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Amir Ben-Shmuel
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Itai Glinert
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Elad Bar-David
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Josef Schlomovitz
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - David Kobiler
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shay Weiss
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Haim Levy
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
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4
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Hess BM, Thomas DG, Weber TJ, Hutchison JR, Straub TM, Bruckner-Lea CJ, Powell JD, Kabilan S, Corley RA. An integrated experimental-computational approach for predicting virulence in New Zealand white rabbits and humans following inhalation exposure to Bacillus anthracis spores. PLoS One 2019; 14:e0219160. [PMID: 31260462 PMCID: PMC6602573 DOI: 10.1371/journal.pone.0219160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 06/12/2019] [Indexed: 11/23/2022] Open
Abstract
Inhalation of Bacillus anthracis spores can lead to an anthrax infection that can be fatal. Previously published mathematical models have extrapolated kinetic rates associated with bacterial growth in New Zealand White (NZW) rabbits to humans, but to date, actual measurements of the underlying processes associated with anthrax virulence between species have not been conducted. To address this knowledge gap, we have quantified species-specific rate constants associated with germination, proliferation, and immune cell inactivation of B. anthracis Sterne using an in vitro test platform that includes primary lung epithelial and immune cells. The generated data was then used to develop a physiologically based biokinetic model (PBBK) which quantitatively compares bacterial growth and mean time to death under lethal conditions in rabbits and humans. Simulations based upon our in vitro data and previously published in vivo data from rabbits indicate that disease progression is likely to be faster in humans than in NZW rabbits under comparable total deposited dose conditions. With the computational framework established, PBBK parameters can now be refined using experimental data for lethal B. anthracis strains (e.g. Ames) under identical conditions in future studies. The PBBK model can also be linked to existing aerosol dosimetry models that account for species-specific differences in aerosol deposition patterns to further improve the human health risk assessment of inhalation anthrax.
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Affiliation(s)
- Becky M. Hess
- Chemical and Biological Signature Sciences, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Dennis G. Thomas
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Thomas J. Weber
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Janine R. Hutchison
- Chemical and Biological Signature Sciences, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Timothy M. Straub
- Chemical and Biological Signature Sciences, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Cynthia J. Bruckner-Lea
- Chemical and Biological Signature Sciences, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Joshua D. Powell
- Chemical and Biological Signature Sciences, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Senthil Kabilan
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Richard A. Corley
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
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Carlson CJ, Kracalik IT, Ross N, Alexander KA, Hugh-Jones ME, Fegan M, Elkin BT, Epp T, Shury TK, Zhang W, Bagirova M, Getz WM, Blackburn JK. The global distribution of Bacillus anthracis and associated anthrax risk to humans, livestock and wildlife. Nat Microbiol 2019; 4:1337-1343. [PMID: 31086311 DOI: 10.1038/s41564-019-0435-4] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/22/2019] [Indexed: 01/25/2023]
Abstract
Bacillus anthracis is a spore-forming, Gram-positive bacterium responsible for anthrax, an acute infection that most significantly affects grazing livestock and wild ungulates, but also poses a threat to human health. The geographic extent of B. anthracis is poorly understood, despite multi-decade research on anthrax epizootic and epidemic dynamics; many countries have limited or inadequate surveillance systems, even within known endemic regions. Here, we compile a global occurrence dataset of human, livestock and wildlife anthrax outbreaks. With these records, we use boosted regression trees to produce a map of the global distribution of B. anthracis as a proxy for anthrax risk. We estimate that 1.83 billion people (95% credible interval (CI): 0.59-4.16 billion) live within regions of anthrax risk, but most of that population faces little occupational exposure. More informatively, a global total of 63.8 million poor livestock keepers (95% CI: 17.5-168.6 million) and 1.1 billion livestock (95% CI: 0.4-2.3 billion) live within vulnerable regions. Human and livestock vulnerability are both concentrated in rural rainfed systems throughout arid and temperate land across Eurasia, Africa and North America. We conclude by mapping where anthrax risk could disrupt sensitive conservation efforts for wild ungulates that coincide with anthrax-prone landscapes.
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Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD, USA.,Department of Biology, Georgetown University, Washington, Washington DC, USA
| | - Ian T Kracalik
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Noam Ross
- EcoHealth Alliance, New York, NY, USA
| | - Kathleen A Alexander
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA
| | - Martin E Hugh-Jones
- School of the Coast and Environment, Louisiana State University, Baton Rouge, LA, USA
| | - Mark Fegan
- AgriBio, Centre for Agribiosciences, Biosciences Research, Department of Economic Development, Jobs, Transport and Resources, Bundoora, Victoria, Australia
| | - Brett T Elkin
- Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, Northwest Territories, Canada
| | - Tasha Epp
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Todd K Shury
- Parks Canada Agency, Saskatoon, Saskatchewan, Canada
| | - Wenyi Zhang
- Center for Disease Surveillance & Research, Institute of Disease Control and Prevention of PLA, Beijing, China
| | | | - Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
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6
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Banked Human Milk and Quantitative Risk Assessment of Bacillus cereus Infection in Premature Infants: A Simulation Study. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2019; 2019:6348281. [PMID: 30863469 PMCID: PMC6378033 DOI: 10.1155/2019/6348281] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/31/2018] [Indexed: 11/17/2022]
Abstract
Background Banked human milk (BHM) offers potential health benefits to premature babies. BHM is pasteurized to mitigate infectious risks, but pasteurization is ineffective against sporulating bacteria such as Bacillus cereus. Sepsis related to Bacillus cereus in premature infants is severe and can often be fatal. Even if a causal link has never been established, BHM has been suggested as a potential source of infection in premature infants. Objective Our aim was to estimate the potential risk of Bacillus cereus infection in preterm infants caused by the ingestion of contaminated pasteurized BHM using different post-pasteurization release criteria (i.e., 9 sampling of 100 microliters versus the HMBANA guideline of 1 sampling of 100 microliters per pool). Methods In the absence of scientific evidence regarding the risk of Bacillus cereus infection by the ingestion of BHM in premature infants, risk assessment using Monte Carlo simulation with the exponential dose-response model was performed. Three scenarios of infectious risk (annual incidence rate of 0.01%, 0.13%, and 0.2%) with 18 variations of the B. cereus virulent dose (from 0.5 CFU/ml to 200 CFU/ml) were simulated. Results The mean risk differential between the two methods of post-pasteurization bacteriological control for realistic infectious doses of 30 to 200 CFU/ml ranges from 0.036 to 0.0054, 0.47 to 0.070, and 0.72 to 0.11 per million servings, for each of the three scenarios. Conclusion Simulation highlights the very small risk of Bacillus cereus infection following the ingestion of pasteurized BHM, even in the worst case scenarios, and suggests that a 100-microliter sample for post-pasteurization culture is sufficient.
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Plowright RK, Parrish CR, McCallum H, Hudson PJ, Ko AI, Graham AL, Lloyd-Smith JO. Pathways to zoonotic spillover. Nat Rev Microbiol 2017; 15:502-510. [PMID: 28555073 PMCID: PMC5791534 DOI: 10.1038/nrmicro.2017.45] [Citation(s) in RCA: 497] [Impact Index Per Article: 71.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Zoonotic spillover, which is the transmission of a pathogen from a vertebrate animal to a human, presents a global public health burden but is a poorly understood phenomenon. Zoonotic spillover requires several factors to align, including the ecological, epidemiological and behavioural determinants of pathogen exposure, and the within-human factors that affect susceptibility to infection. In this Opinion article, we propose a synthetic framework for animal-to-human transmission that integrates the relevant mechanisms. This framework reveals that all zoonotic pathogens must overcome a hierarchical series of barriers to cause spillover infections in humans. Understanding how these barriers are functionally and quantitatively linked, and how they interact in space and time, will substantially improve our ability to predict or prevent spillover events. This work provides a foundation for transdisciplinary investigation of spillover and synthetic theory on zoonotic transmission.
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Affiliation(s)
- Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Colin R Parrish
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Hamish McCallum
- Griffith School of Environment, Griffith University, Brisbane, Queensland 4111, Australia
| | - Peter J Hudson
- Center for Infectious Disease Dynamics, Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut 06520-8034, USA
| | - Andrea L Graham
- Department of Ecology &Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - James O Lloyd-Smith
- Department of Ecology &Evolutionary Biology, University of California, Los Angeles, Los Angeles, California 90095-7239, USA; and at Fogarty International Center, National Institutes of Health, Bethesda, Maryland 20892-2220, USA
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8
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Gutting BW, Rukhin A, Marchette D, Mackie RS, Thran B. Dose-Response Modeling for Inhalational Anthrax in Rabbits Following Single or Multiple Exposures. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2016; 36:2031-2038. [PMID: 26889937 DOI: 10.1111/risa.12564] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There is a need to advance our ability to characterize the risk of inhalational anthrax following a low-dose exposure. The exposure scenario most often considered is a single exposure that occurs during an attack. However, long-term daily low-dose exposures also represent a realistic exposure scenario, such as what may be encountered by people occupying areas for longer periods. Given this, the objective of the current work was to model two rabbit inhalational anthrax dose-response data sets. One data set was from single exposures to aerosolized Bacillus anthracis Ames spores. The second data set exposed rabbits repeatedly to aerosols of B. anthracis Ames spores. For the multiple exposure data the cumulative dose (i.e., the sum of the individual daily doses) was used for the model. Lethality was the response for both. Modeling was performed using Benchmark Dose Software evaluating six models: logprobit, loglogistic, Weibull, exponential, gamma, and dichotomous-Hill. All models produced acceptable fits to either data set. The exponential model was identified as the best fitting model for both data sets. Statistical tests suggested there was no significant difference between the single exposure exponential model results and the multiple exposure exponential model results, which suggests the risk of disease is similar between the two data sets. The dose expected to cause 10% lethality was 15,600 inhaled spores and 18,200 inhaled spores for the single exposure and multiple exposure exponential dose-response model, respectively, and the 95% lower confidence intervals were 9,800 inhaled spores and 9,200 inhaled spores, respectively.
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Affiliation(s)
- Bradford W Gutting
- CBR Concepts and Experimentation Branch (B21), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Andrey Rukhin
- Sensor Fusion Branch (A43), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - David Marchette
- Sensor Fusion Branch (A43), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Ryan S Mackie
- CBR Concepts and Experimentation Branch (B21), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Brandolyn Thran
- Army Public Health Center (Provisional), Aberdeen Proving Ground, MD, USA
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Kabilan S, Suffield S, Recknagle K, Jacob R, Einstein D, Kuprat A, Carson J, Colby S, Saunders J, Hines S, Teeguarden J, Straub T, Moe M, Taft S, Corley R. Computational fluid dynamics modeling of Bacillus anthracis spore deposition in rabbit and human respiratory airways. JOURNAL OF AEROSOL SCIENCE 2016; 99:64-77. [PMID: 33311732 PMCID: PMC7731948 DOI: 10.1016/j.jaerosci.2016.01.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived respectively from computed tomography (CT) and μCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation-exhalation breathing conditions using average species-specific minute volumes. Two different exposure scenarios were modeled in the rabbit based upon experimental inhalation studies. For comparison, human simulations were conducted at the highest exposure concentration used during the rabbit experimental exposures. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Due to the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the nasal sinus compared to the human at the same air concentration of anthrax spores. In contrast, higher spore deposition was predicted in the lower conducting airways of the human compared to the rabbit lung due to differences in airway branching pattern. This information can be used to refine published and ongoing biokinetic models of inhalation anthrax spore exposures, which currently estimate deposited spore concentrations based solely upon exposure concentrations and inhaled doses that do not factor in species-specific anatomy and physiology for deposition.
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Affiliation(s)
- S. Kabilan
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - S.R. Suffield
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - K.P. Recknagle
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - R.E. Jacob
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - D.R. Einstein
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - A.P. Kuprat
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - J.P. Carson
- Texas Advanced Computing Center, Austin, TX 78758, United States
| | - S.M Colby
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - J.H. Saunders
- Battelle, 505 King Avenue, Columbus, OH 43201, United States
| | - S.A. Hines
- Battelle, 505 King Avenue, Columbus, OH 43201, United States
| | - J.G. Teeguarden
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - T.M. Straub
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
| | - M. Moe
- Department of Homeland Security, Science and Technology Directorate, Washington, DC 20528, United States
| | - S.C. Taft
- U.S. Environmental Protection Agency, National Homeland Security Research Center, Threat and Consequence Assessment Division, Cincinnati, OH 45268, United States
| | - R.A. Corley
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN J4-16, Richland, WA 99352, United States
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Animal Models for the Pathogenesis, Treatment, and Prevention of Infection by Bacillus anthracis. Microbiol Spectr 2016; 3:TBS-0001-2012. [PMID: 26104551 DOI: 10.1128/microbiolspec.tbs-0001-2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This article reviews the characteristics of the major animal models utilized for studies on Bacillus anthracis and highlights their contributions to understanding the pathogenesis and host responses to anthrax and its treatment and prevention. Advantages and drawbacks associated with each model, to include the major models (murine, guinea pig, rabbit, nonhuman primate, and rat), and other less frequently utilized models, are discussed. Although the three principal forms of anthrax are addressed, the main focus of this review is on models for inhalational anthrax. The selection of an animal model for study is often not straightforward and is dependent on the specific aims of the research or test. No single animal species provides complete equivalence to humans; however, each species, when used appropriately, can contribute to a more complete understanding of anthrax and its etiologic agent.
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11
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Asgharian B, Price O, Kabilan S, Jacob RE, Einstein DR, Kuprat A, Corley RA. Development of a Zealand white rabbit deposition model to study inhalation anthrax. Inhal Toxicol 2016; 28:80-8. [PMID: 26895308 PMCID: PMC4968080 DOI: 10.3109/08958378.2016.1140850] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Despite using rabbits in several inhalation exposure experiments to study diseases such as anthrax, there is a lack of understanding regarding deposition characteristics and fate of inhaled particles (bio-aerosols and viruses) in the respiratory tracts of rabbits. Such information allows dosimetric extrapolation to humans to inform human outcomes. The lung geometry of the New Zealand white rabbit (referred to simply as rabbits throughout the article) was constructed using recently acquired scanned images of the conducting airways of rabbits and available information on its acinar region. In addition, functional relationships were developed for the lung and breathing parameters of rabbits as a function of body weight. The lung geometry and breathing parameters were used to extend the existing deposition model for humans and several other species to rabbits. Evaluation of the deposition model for rabbits was made by comparing predictions with available measurements in the literature. Deposition predictions in the lungs of rabbits indicated smaller deposition fractions compared to those found in humans across various particle diameter ranges. The application of the deposition model for rabbits was demonstrated by extrapolating deposition predictions in rabbits to find equivalent human exposure concentrations assuming the same dose-response relationship between the two species. Human equivalent exposure concentration levels were found to be much smaller than those for rabbits.
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Affiliation(s)
- Bahman Asgharian
- Applied Research Associates, Inc., 8537 Six Forks Road, Suite 600, Raleigh, NC 27615-2963
| | - Owen Price
- Applied Research Associates, Inc., 801 North Quincy Street, Suite 700, Arlington, VA 22203
| | - Senthil Kabilan
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352
| | - Richard E. Jacob
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352
| | - Daniel R. Einstein
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352
| | | | - Richard A. Corley
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352
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12
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Gutting BW, Rukhin A, Mackie RS, Marchette D, Thran B. Evaluation of Inhaled Versus Deposited Dose Using the Exponential Dose-Response Model for Inhalational Anthrax in Nonhuman Primate, Rabbit, and Guinea Pig. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2015; 35:811-827. [PMID: 25545587 DOI: 10.1111/risa.12326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The application of the exponential model is extended by the inclusion of new nonhuman primate (NHP), rabbit, and guinea pig dose-lethality data for inhalation anthrax. Because deposition is a critical step in the initiation of inhalation anthrax, inhaled doses may not provide the most accurate cross-species comparison. For this reason, species-specific deposition factors were derived to translate inhaled dose to deposited dose. Four NHP, three rabbit, and two guinea pig data sets were utilized. Results from species-specific pooling analysis suggested all four NHP data sets could be pooled into a single NHP data set, which was also true for the rabbit and guinea pig data sets. The three species-specific pooled data sets could not be combined into a single generic mammalian data set. For inhaled dose, NHPs were the most sensitive (relative lowest LD50) species and rabbits the least. Improved inhaled LD50 s proposed for use in risk assessment are 50,600, 102,600, and 70,800 inhaled spores for NHP, rabbit, and guinea pig, respectively. Lung deposition factors were estimated for each species using published deposition data from Bacillus spore exposures, particle deposition studies, and computer modeling. Deposition was estimated at 22%, 9%, and 30% of the inhaled dose for NHP, rabbit, and guinea pig, respectively. When the inhaled dose was adjusted to reflect deposited dose, the rabbit animal model appears the most sensitive with the guinea pig the least sensitive species.
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Affiliation(s)
- Bradford W Gutting
- CBR Concepts and Experimentation Branch (Z21), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Andrey Rukhin
- Sensor Fusion Branch (Q33), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Ryan S Mackie
- CBR Concepts and Experimentation Branch (Z21), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - David Marchette
- Sensor Fusion Branch (Q33), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA
| | - Brandolyn Thran
- U.S. Army Public Health Command, Aberdeen Proving Ground, MD, USA
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Cornforth DM, Matthews A, Brown SP, Raymond B. Bacterial Cooperation Causes Systematic Errors in Pathogen Risk Assessment due to the Failure of the Independent Action Hypothesis. PLoS Pathog 2015; 11:e1004775. [PMID: 25909384 PMCID: PMC4409216 DOI: 10.1371/journal.ppat.1004775] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 03/03/2015] [Indexed: 11/19/2022] Open
Abstract
The Independent Action Hypothesis (IAH) states that pathogenic individuals (cells, spores, virus particles etc.) behave independently of each other, so that each has an independent probability of causing systemic infection or death. The IAH is not just of basic scientific interest; it forms the basis of our current estimates of infectious disease risk in humans. Despite the important role of the IAH in managing disease interventions for food and water-borne pathogens, experimental support for the IAH in bacterial pathogens is indirect at best. Moreover since the IAH was first proposed, cooperative behaviors have been discovered in a wide range of microorganisms, including many pathogens. A fundamental principle of cooperation is that the fitness of individuals is affected by the presence and behaviors of others, which is contrary to the assumption of independent action. In this paper, we test the IAH in Bacillus thuringiensis (B.t), a widely occurring insect pathogen that releases toxins that benefit others in the inoculum, infecting the diamondback moth, Plutella xylostella. By experimentally separating B.t. spores from their toxins, we demonstrate that the IAH fails because there is an interaction between toxin and spore effects on mortality, where the toxin effect is synergistic and cannot be accommodated by independence assumptions. Finally, we show that applying recommended IAH dose-response models to high dose data leads to systematic overestimation of mortality risks at low doses, due to the presence of synergistic pathogen interactions. Our results show that cooperative secretions can easily invalidate the IAH, and that such mechanistic details should be incorporated into pathogen risk analysis.
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Affiliation(s)
- Daniel M. Cornforth
- Department of Molecular Biosciences, The University of Texas, Austin, Austin, Texas, United States of America
- * E-mail: (DMC); (BR)
| | - Andrew Matthews
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, United Kingdom
| | - Sam P. Brown
- Centre for Immunity, Infection and Immunity, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ben Raymond
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, United Kingdom
- * E-mail: (DMC); (BR)
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Gutting B. Deterministic models of inhalational anthrax in New Zealand white rabbits. Biosecur Bioterror 2014; 12:29-41. [PMID: 24527843 PMCID: PMC3934436 DOI: 10.1089/bsp.2013.0067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 12/09/2013] [Indexed: 11/12/2022]
Abstract
Computational models describing bacterial kinetics were developed for inhalational anthrax in New Zealand white (NZW) rabbits following inhalation of Ames strain B. anthracis. The data used to parameterize the models included bacterial numbers in the airways, lung tissue, draining lymph nodes, and blood. Initial bacterial numbers were deposited spore dose. The first model was a single exponential ordinary differential equation (ODE) with 3 rate parameters that described mucociliated (physical) clearance, immune clearance (bacterial killing), and bacterial growth. At 36 hours postexposure, the ODE model predicted 1.7×10⁷ bacteria in the rabbit, which agreed well with data from actual experiments (4.0×10⁷ bacteria at 36 hours). Next, building on the single ODE model, a physiological-based biokinetic (PBBK) compartmentalized model was developed in which 1 physiological compartment was the lumen of the airways and the other was the rabbit body (lung tissue, lymph nodes, blood). The 2 compartments were connected with a parameter describing transport of bacteria from the airways into the body. The PBBK model predicted 4.9×10⁷ bacteria in the body at 36 hours, and by 45 hours the model showed all clearance mechanisms were saturated, suggesting the rabbit would quickly succumb to the infection. As with the ODE model, the PBBK model results agreed well with laboratory observations. These data are discussed along with the need for and potential application of the models in risk assessment, drug development, and as a general aid to the experimentalist studying inhalational anthrax.
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Affiliation(s)
- Bradford Gutting
- Bradford Gutting, PhD, is a Toxicologist, Naval Surface Warfare Center Dahlgren Division (NSWCDD) , Dahlgren, Virginia
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15
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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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16
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Gutting BW, Marchette D, Sherwood R, Andrews GA, Director-Myska A, Channel SR, Wolfe D, Berger AE, Mackie RS, Watson BJ, Rukhin A. Modeling low-dose mortality and disease incubation period of inhalational anthrax in the rabbit. J Theor Biol 2013; 329:20-31. [PMID: 23567649 DOI: 10.1016/j.jtbi.2013.03.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 03/14/2013] [Accepted: 03/21/2013] [Indexed: 01/03/2023]
Abstract
There is a need to advance our ability to conduct credible human risk assessments for inhalational anthrax associated with exposure to a low number of bacteria. Combining animal data with computational models of disease will be central in the low-dose and cross-species extrapolations required in achieving this goal. The objective of the current work was to apply and advance the competing risks (CR) computational model of inhalational anthrax where data was collected from NZW rabbits exposed to aerosols of Ames strain Bacillus anthracis. An initial aim was to parameterize the CR model using high-dose rabbit data and then conduct a low-dose extrapolation. The CR low-dose attack rate was then compared against known low-dose rabbit data as well as the low-dose curve obtained when the entire rabbit dose-response data set was fitted to an exponential dose-response (EDR) model. The CR model predictions demonstrated excellent agreement with actual low-dose rabbit data. We next used a modified CR model (MCR) to examine disease incubation period (the time to reach a fever >40 °C). The MCR model predicted a germination period of 14.5h following exposure to a low spore dose, which was confirmed by monitoring spore germination in the rabbit lung using PCR, and predicted a low-dose disease incubation period in the rabbit between 14.7 and 16.8 days. Overall, the CR and MCR model appeared to describe rabbit inhalational anthrax well. These results are discussed in the context of conducting laboratory studies in other relevant animal models, combining the CR/MCR model with other computation models of inhalational anthrax, and using the resulting information towards extrapolating a low-dose response prediction for man.
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Affiliation(s)
- Bradford W Gutting
- CBR Concepts and Experimentation Branch (Z21), Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA, USA.
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17
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Taft SC, Hines SA. Benchmark dose analysis for Bacillus anthracis inhalation exposures in the nonhuman primate. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2012; 32:1750-1768. [PMID: 22469218 DOI: 10.1111/j.1539-6924.2012.01808.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
There is considerable variability in the published lethality values for inhalation exposures of Bacillus anthracis. The lack of consensus on an acceptable dose-response relationship poses a significant challenge in the development of risk-based management approaches for use following a terrorist release of B. anthracis spores. This article reviewed available B. anthracis dose-response modeling and literature for the nonhuman primate, evaluated the use of the U.S. Environmental Protection Agency's Benchmark Dose Software (BMDS) to fit mathematical dose-response models to these data, and reported results of the benchmark dose analysis of suitable data sets. The BMDS was found to be a useful tool to evaluate dose-response relationships in microbial data, including that from B. anthracis exposure. An evaluation of the sources of variability identified in the published lethality data and the corresponding BMDS-derived lethality values found that varying levels of physical characterization of the spore product, differing receptor-specific exposure assumptions, choice of dose metrics, and the selected statistical methods all contributed to differences in lethality estimates. Recognition of these contributors to variability could ultimately facilitate agreement on a B. anthracis dose-response relationship through provision of a common description of necessary study considerations for acceptable dose-response data sets.
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Affiliation(s)
- Sarah C Taft
- U.S. Environmental Protection Agency, National Homeland Security Research Center, Cincinnati, OH, USA.
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18
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Fay MP, Follmann DA, Lynn F, Schiffer JM, Stark GV, Kohberger R, Quinn CP, Nuzum EO. Anthrax vaccine-induced antibodies provide cross-species prediction of survival to aerosol challenge. Sci Transl Med 2012; 4:151ra126. [PMID: 22972844 PMCID: PMC3668972 DOI: 10.1126/scitranslmed.3004073] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Because clinical trials to assess the efficacy of vaccines against anthrax are not ethical or feasible, licensure for new anthrax vaccines will likely involve the Food and Drug Administration's "Animal Rule," a set of regulations that allow approval of products based on efficacy data only in animals combined with immunogenicity and safety data in animals and humans. U.S. government-sponsored animal studies have shown anthrax vaccine efficacy in a variety of settings. We examined data from 21 of those studies to determine whether an immunological bridge based on lethal toxin neutralization activity assay (TNA) can predict survival against an inhalation anthrax challenge within and across species and genera. The 21 studies were classified into 11 different settings, each of which had the same animal species, vaccine type and formulation, vaccination schedule, time of TNA measurement, and challenge time. Logistic regression models determined the contribution of vaccine dilution dose and TNA on prediction of survival. For most settings, logistic models using only TNA explained more than 75% of the survival effect of the models with dose additionally included. Cross-species survival predictions using TNA were compared to the actual survival and shown to have good agreement (Cohen's κ ranged from 0.55 to 0.78). In one study design, cynomolgus macaque data predicted 78.6% survival in rhesus macaques (actual survival, 83.0%) and 72.6% in rabbits (actual survival, 64.6%). These data add support for the use of TNA as an immunological bridge between species to extrapolate data in animals to predict anthrax vaccine effectiveness in humans.
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Affiliation(s)
- Michael P Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, 6700B Rockledge Drive, Bethesda, MD 20892-7630, USA.
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19
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Hong T, Gurian PL. Characterizing bioaerosol risk from environmental sampling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:6714-6722. [PMID: 22568610 DOI: 10.1021/es300197n] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the aftermath of a release of microbiological agents, environmental sampling must be conducted to characterize the release sufficiently so that mathematical models can then be used to predict the subsequent dispersion and human health risks. Because both the dose-response and environmental transport of aerosolized microbiological agents are functions of the effective aerodynamic diameter of the particles, environmental assessments should consider not only the total amount of agents but also the size distributions of the aerosolized particles. However, typical surface sampling cannot readily distinguish among different size particles. This study evaluates different approaches to estimating risk from measurements of microorganisms deposited on surfaces after an aerosol release. For various combinations of sampling surfaces, size fractions, HVAC operating conditions, size distributions of release spores, uncertainties in surface measurements, and the accuracy of model predictions are tested in order to assess how much detail can realistically be identified from surface sampling results. The recommended modeling and sampling scheme is one choosing 3, 5, and 10 μm diameter particles as identification targets and taking samples from untracked floor, wall, and the HVAC filter. This scheme provides reasonably accurate, but somewhat conservative, estimates of risk across a range of different scenarios. Performance of the recommended sampling scheme is tested by using data from a large-scale field test as a case study. Sample sizes of 10-25 in each homogeneously mixed environmental compartment are sufficient to develop order of magnitude estimates of risk. Larger sample sizes have little benefit unless uncertainties in sample recoveries can be reduced.
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Affiliation(s)
- Tao Hong
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States.
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20
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Mitchell-Blackwood J, Gurian P, Lee R, Thran B. Variance in Bacillus anthracis virulence assessed through Bayesian hierarchical dose-response modelling. J Appl Microbiol 2012; 113:265-75. [DOI: 10.1111/j.1365-2672.2012.05311.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Bensman MD, Mackie RS, Minter ZA, Gutting BW. Effect of animal sera on Bacillus anthracis Sterne spore germination and vegetative cell growth. J Appl Microbiol 2012; 113:276-83. [PMID: 22515644 DOI: 10.1111/j.1365-2672.2012.05314.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AIMS The aims of this work were to investigate the effects of sera on B. anthracis Sterne germination and growth. Sera examined included human, monkey and rabbit sera, as well as sera from eight other species. METHODS AND RESULTS Standard dilution plate assay (with and without heat kill) was used as a measure of germination, and spectroscopy was used to measure growth. In addition, a Coulter Counter particle counter was used to monitor germination and growth based on bacterial size. Spores germinated best in foetal bovine and monkey sera, moderately with human sera and showed limited germination in the presence of rabbit or rat sera. Vegetative bacteria grew best in foetal bovine sera and moderately in rabbit sera. Human and monkey sera supported little growth of vegetative bacteria. CONCLUSION The data suggested sera can have a significant impact on germination and growth of Sterne bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY These data should be considered when conducting in vitro cell culture studies and may aid in interpreting in vivo infection studies.
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Affiliation(s)
- M D Bensman
- Dahlgren Division, CBR Concepts and Experimentation Branch-Z21, Naval Surface Warfare Center, Dahlgren, VA, USA
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22
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Froude JW, Stiles B, Pelat T, Thullier P. Antibodies for biodefense. MAbs 2011; 3:517-27. [PMID: 22123065 PMCID: PMC3242838 DOI: 10.4161/mabs.3.6.17621] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 08/03/2011] [Indexed: 12/11/2022] Open
Abstract
Potential bioweapons are biological agents (bacteria, viruses, and toxins) at risk of intentional dissemination. Biodefense, defined as development of therapeutics and vaccines against these agents, has seen an increase, particularly in the US following the 2001 anthrax attack. This review focuses on recombinant antibodies and polyclonal antibodies for biodefense that have been accepted for clinical use. These antibodies aim to protect against primary potential bioweapons, or category A agents as defined by the Centers for Disease Control and Prevention (Bacillus anthracis, Yersinia pestis, Francisella tularensis, botulinum neurotoxins, smallpox virus, and certain others causing viral hemorrhagic fevers) and certain category B agents. Potential for prophylactic use is presented, as well as frequent use of oligoclonal antibodies or synergistic effect with other molecules. Capacities and limitations of antibodies for use in biodefense are discussed, and are generally applicable to the field of infectious diseases.
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Affiliation(s)
- Jeffrey W Froude
- US Army Medical Research and Material Command; Fort Detrick, MD USA
- Unité de biotechnologie des anticorps et des toxines; Département de Microbiologie; Institut de Recherche Biomédicale des Armées (IRBA-CRSSA); La Tronche Cedex, France
| | - Bradley Stiles
- US Army Medical Research Institute of Infectious Diseases; Fort Detrick, MD USA
| | - Thibaut Pelat
- Unité de biotechnologie des anticorps et des toxines; Département de Microbiologie; Institut de Recherche Biomédicale des Armées (IRBA-CRSSA); La Tronche Cedex, France
| | - Philippe Thullier
- Unité de biotechnologie des anticorps et des toxines; Département de Microbiologie; Institut de Recherche Biomédicale des Armées (IRBA-CRSSA); La Tronche Cedex, France
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Xie T, Auth RD, Frucht DM. The effects of anthrax lethal toxin on host barrier function. Toxins (Basel) 2011; 3:591-607. [PMID: 22069727 PMCID: PMC3202839 DOI: 10.3390/toxins3060591] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 06/02/2011] [Accepted: 06/07/2011] [Indexed: 01/08/2023] Open
Abstract
The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.
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Affiliation(s)
- Tao Xie
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Office of Pharmaceutical Science, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Bethesda, MD 20892, USA.
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24
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Rietjens IMCM, Louisse J, Punt A. Tutorial on physiologically based kinetic modeling in molecular nutrition and food research. Mol Nutr Food Res 2011; 55:941-56. [DOI: 10.1002/mnfr.201000655] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 02/15/2011] [Accepted: 02/18/2011] [Indexed: 11/11/2022]
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25
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Day J, Friedman A, Schlesinger LS. Modeling the host response to inhalation anthrax. J Theor Biol 2011; 276:199-208. [PMID: 21295589 DOI: 10.1016/j.jtbi.2011.01.054] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 12/14/2010] [Accepted: 01/31/2011] [Indexed: 12/19/2022]
Abstract
Inhalation anthrax, an often fatal infection, is initiated by endospores of the bacterium Bacillus anthracis, which are introduced into the lung. To better understand the pathogenesis of an inhalation anthrax infection, we propose a two-compartment mathematical model that takes into account the documented early events of such an infection. Anthrax spores, once inhaled, are readily taken up by alveolar phagocytes, which then migrate rather quickly out of the lung and into the thoracic/mediastinal lymph nodes. En route, these spores germinate to become vegetative bacteria. In the lymph nodes, the bacteria kill the host cells and are released into the extracellular environment where they can be disseminated into the blood stream and grow to a very high level, often resulting in the death of the infected person. Using this framework as the basis of our model, we explore the probability of survival of an infected individual. This is dependent on several factors, such as the rate of migration and germination events and treatment with antibiotics.
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Affiliation(s)
- Judy Day
- Mathematical Biosciences Institute, 3rd Floor Jennings Hall, The Ohio State University, Columbus, OH 43210, USA.
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Hong T, Gurian PL, Ward NFD. Setting risk-informed environmental standards for Bacillus anthracis spores. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2010; 30:1602-1622. [PMID: 20626695 DOI: 10.1111/j.1539-6924.2010.01443.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In many cases, human health risk from biological agents is associated with aerosol exposures. Because air concentrations decline rapidly after a release, it may be necessary to use concentrations found in other environmental media to infer future or past aerosol exposures. This article presents an approach for linking environmental concentrations of Bacillus. anthracis (B. anthracis) spores on walls, floors, ventilation system filters, and in human nasal passages with human health risk from exposure to B. anthracis spores. This approach is then used to calculate example values of risk-informed concentration standards for both retrospective risk mitigation (e.g., prophylactic antibiotics) and prospective risk mitigation (e.g., environmental clean up and reoccupancy). A large number of assumptions are required to calculate these values, and the resulting values have large uncertainties associated with them. The values calculated here suggest that documenting compliance with risks in the range of 10(-4) to 10(-6) would be challenging for small diameter (respirable) spore particles. For less stringent risk targets and for releases of larger diameter particles (which are less respirable and hence less hazardous), environmental sampling would be more promising.
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Affiliation(s)
- Tao Hong
- Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA
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