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Prioritizing risks and uncertainties from intentional release of selected Category A pathogens.

Hong T, Gurian PL, Huang Y, Haas CN - PLoS ONE (2012)

Bottom Line: Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces.A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties.An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, United States of America. hongtao510@gmail.com

ABSTRACT
This paper synthesizes available information on five Category A pathogens (Bacillus anthracis, Yersinia pestis, Francisella tularensis, Variola major and Lassa) to develop quantitative guidelines for how environmental pathogen concentrations may be related to human health risk in an indoor environment. An integrated model of environmental transport and human health exposure to biological pathogens is constructed which 1) includes the effects of environmental attenuation, 2) considers fomite contact exposure as well as inhalational exposure, and 3) includes an uncertainty analysis to identify key input uncertainties, which may inform future research directions. The findings provide a framework for developing the many different environmental standards that are needed for making risk-informed response decisions, such as when prophylactic antibiotics should be distributed, and whether or not a contaminated area should be cleaned up. The approach is based on the assumption of uniform mixing in environmental compartments and is thus applicable to areas sufficiently removed in time and space from the initial release that mixing has produced relatively uniform concentrations. Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces. Concentrations sampled from untracked floor, walls and the filter of heating ventilation and air conditioning (HVAC) system are proposed as indicators of previous exposure risk, while samples taken from touched surfaces are proposed as indicators of future risk if the building is reoccupied. A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties. An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities.

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Different types of risks associated with surface release of 1 micron Category A pathogens.(Release quantity is 1000 unclumped pathogens. For B. anthracis, the ingestion risk is replaced by cutaneous risk since the fractions of inhalational anthrax and cutaneous anthrax were the same in the 2001 anthrax letters attacks [6]).
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pone-0032732-g003: Different types of risks associated with surface release of 1 micron Category A pathogens.(Release quantity is 1000 unclumped pathogens. For B. anthracis, the ingestion risk is replaced by cutaneous risk since the fractions of inhalational anthrax and cutaneous anthrax were the same in the 2001 anthrax letters attacks [6]).

Mentions: Figure 3 presents different types of risks associated with the presence of 1 micron Category A pathogens on surfaces (i.e., the prospective scenario). In this case total risk and ingestion risk match so closely as to be indistinguishable, indicating that risk from ingestion (dermal contact for B. anthracis) is the main component of overall risk. In Figure 3, the time scale over which each pathogen's overall risk reaches its asymptote varies over 4 orders of magnitude, which can be explained by the huge variability among pathogen attenuation rates.


Prioritizing risks and uncertainties from intentional release of selected Category A pathogens.

Hong T, Gurian PL, Huang Y, Haas CN - PLoS ONE (2012)

Different types of risks associated with surface release of 1 micron Category A pathogens.(Release quantity is 1000 unclumped pathogens. For B. anthracis, the ingestion risk is replaced by cutaneous risk since the fractions of inhalational anthrax and cutaneous anthrax were the same in the 2001 anthrax letters attacks [6]).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3295774&req=5

pone-0032732-g003: Different types of risks associated with surface release of 1 micron Category A pathogens.(Release quantity is 1000 unclumped pathogens. For B. anthracis, the ingestion risk is replaced by cutaneous risk since the fractions of inhalational anthrax and cutaneous anthrax were the same in the 2001 anthrax letters attacks [6]).
Mentions: Figure 3 presents different types of risks associated with the presence of 1 micron Category A pathogens on surfaces (i.e., the prospective scenario). In this case total risk and ingestion risk match so closely as to be indistinguishable, indicating that risk from ingestion (dermal contact for B. anthracis) is the main component of overall risk. In Figure 3, the time scale over which each pathogen's overall risk reaches its asymptote varies over 4 orders of magnitude, which can be explained by the huge variability among pathogen attenuation rates.

Bottom Line: Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces.A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties.An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, United States of America. hongtao510@gmail.com

ABSTRACT
This paper synthesizes available information on five Category A pathogens (Bacillus anthracis, Yersinia pestis, Francisella tularensis, Variola major and Lassa) to develop quantitative guidelines for how environmental pathogen concentrations may be related to human health risk in an indoor environment. An integrated model of environmental transport and human health exposure to biological pathogens is constructed which 1) includes the effects of environmental attenuation, 2) considers fomite contact exposure as well as inhalational exposure, and 3) includes an uncertainty analysis to identify key input uncertainties, which may inform future research directions. The findings provide a framework for developing the many different environmental standards that are needed for making risk-informed response decisions, such as when prophylactic antibiotics should be distributed, and whether or not a contaminated area should be cleaned up. The approach is based on the assumption of uniform mixing in environmental compartments and is thus applicable to areas sufficiently removed in time and space from the initial release that mixing has produced relatively uniform concentrations. Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces. Concentrations sampled from untracked floor, walls and the filter of heating ventilation and air conditioning (HVAC) system are proposed as indicators of previous exposure risk, while samples taken from touched surfaces are proposed as indicators of future risk if the building is reoccupied. A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties. An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities.

Show MeSH
Related in: MedlinePlus