Risk assessment model for a waterborne outbreak of cryptosporidiosis

2000 ◽  
Vol 41 (7) ◽  
pp. 1-7 ◽  
Author(s):  
P. Gale
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Arithmetic Mean ◽  
Assessment Model ◽  
Temporal Heterogeneity ◽  
Risk Assessment Model ◽  
Risk Of Infection ◽  
Treated Water ◽  
Waterborne Outbreak ◽  
Cryptosporidium Oocysts

Counts of Cryptosporidium oocysts in 100L volumes of treated water are simulated for conditions representative of a waterborne outbreak in a surface water-derived supply. Assuming oocysts act independently during infection, the risk of infection is directly related to the arithmetic mean oocyst density in the water supply, which is in turn related to the total number of oocysts which break through treatment. Spatial/temporal heterogeneity of oocyst concentrations in the treated water contributes to monitoring programmes based on “spot-sampling” underestimating the arithmetic mean oocyst density and hence the risk of infection. This could contribute to the reported lack of a clear association between oocyst concentrations measured in drinking water supplies and the risk of waterborne outbreak of cryptosporidiosis in the population. An increase in spatial heterogeneity of oocysts during treatment could also contribute to an overestimation of the net oocyst removal by treatment.

scholarly journals A computational model for predicting changes in infection dynamics due to leakage through N95 respirators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Prasanna Hariharan ◽  
Neha Sharma ◽  
Suvajyoti Guha ◽  
Rupak K. Banerjee ◽  
Gavin D’Souza ◽  
...  
Keyword(s):  
Experimental Data ◽  
Risk Assessment ◽  
Assessment Model ◽  
Sample Population ◽  
Risk Assessment Model ◽  
Risk Of Infection ◽  
Influenza Outbreak ◽  
Exposed Population ◽  
The Face ◽  
N95 Respirators

AbstractIn the absence of fit-testing, leakage of aerosolized pathogens through the gaps between the face and N95 respirators could compromise the effectiveness of the device and increase the risk of infection for the exposed population. To address this issue, we have developed a model to estimate the increase in risk of infection resulting from aerosols leaking through gaps between the face and N95 respirators. The gaps between anthropometric face-geometry and N95 respirators were scanned using computed tomography. The gap profiles were subsequently input into CFD models. The amount of aerosol leakage was predicted by the CFD simulations. Leakage levels were validated using experimental data obtained using manikins. The computed amounts of aerosol transmitted to the respiratory system, with and without leaks, were then linked to a risk-assessment model to predict the infection risk for a sample population. An influenza outbreak in which 50% of the population deployed respirators was considered for risk assessment. Our results showed that the leakage predicted by the CFD model matched the experimental data within about 13%. Depending upon the fit between the headform and the respirator, the inward leakage for the aerosols ranged between 30 and 95%. In addition, the non-fit-tested respirator lowered the infection rate from 97% (for no protection) to between 42 and 80%, but not to the same level as the fit-tested respirators (12%). The CFD-based leakage model, combined with the risk-assessment model, can be useful in optimizing protection strategies for a given population exposed to a pathogenic aerosol.

scholarly journals Water Quality Pollutants and Health Risk assessment for Four Different Drinking Water Sources

2019 ◽  
Vol 78 ◽  
pp. 03004
Author(s):  
Miaomiao Tian ◽  
Wenzhao Li ◽  
Meijuan Ruan ◽  
Jing Wei ◽  
Weiwei Ma
Keyword(s):  
Water Quality ◽  
Risk Assessment ◽  
Drinking Water ◽  
Health Risk ◽  
Health Risk Assessment ◽  
Rural Areas ◽  
Assessment Model ◽  
Risk Level ◽  
Risk Assessment Model ◽  
Acceptable Risk

Drinking water quality has become a great concern to the whole society, especially in heavily polluted rural areas. This paper analyzes the water quality of 100 water supping the US Environmental Protection Agency's (USEPA) recommended health risk assessment model. The results showed that the microbial indicators exceeded the standard in the whole year, and some of the water supply units which lead, nitrated and dissolved solids exceeding the standard. The model recommended by EPA is applied to establish risk assessment model for health risk assessment of adults in wet and dry seasons, respectively. Results of HRA indicated that carcinogenic risk of chromium was 7.61E-05a-1 and the risk value of arsenic was 9.92E-06a-1 which exceed the maximum acceptable risk level recommended by USEPA 5.0×10-5 closely to the ICPR recommendation 1.0×10-6. Meanwhile we conduct health risk assessment (HRA) on relevant non-carcinogenic indicators: nitrate is 2.95E-09a-1, the risk value of fluoride (F) is 2.49E-09a-1, the risk value of lead is 2.39E-09a-1 and copper (Cu) 9.00E-10a-1 exceeds the maximum acceptable risk level risk value recommended by USEPA 1.0×10-9. The above indicators require priority control and management of pollutants that are prioritized and managed.

Risk assessment model for venous thromboembolism in hospitalized surgical and non-surgical patients in the 4th Hungarian Antithrombotic Guidelines entitled “Diminution and Treatment of Venous Thromboembolism”

2010 ◽  
Vol 151 (34) ◽  
pp. 1365-1374 ◽  
Author(s):  
Marianna Dávid ◽  
Hajna Losonczy ◽  
Miklós Udvardy ◽  
Zoltán Boda ◽  
György Blaskó ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Venous Thromboembolism ◽  
Assessment Model ◽  
Surgical Patients ◽  
Risk Assessment Model

A kórházban kezelt sebészeti és belgyógyászati betegekben jelentős a vénásthromboembolia-rizikó. Profilaxis nélkül, a műtét típusától függően, a sebészeti beavatkozások kapcsán a betegek 15–60%-ában alakul ki mélyvénás trombózis vagy tüdőembólia, és az utóbbi ma is vezető kórházi halálok. Bár a vénás thromboemboliát leggyakrabban a közelmúltban végzett műtéttel vagy traumával hozzák kapcsolatba, a szimptómás thromboemboliás események 50–70%-a és a fatális tüdőembóliák 70–80%-a nem a sebészeti betegekben alakul ki. Nemzetközi és hazai felmérések alapján a nagy kockázattal rendelkező sebészeti betegek többsége megkapja a szükséges trombózisprofilaxist. Azonban profilaxis nélkül marad a rizikóval rendelkező belgyógyászati betegek jelentős része, a konszenzuson alapuló nemzetközi és hazai irányelvi ajánlások ellenére. A belgyógyászati betegek körében növelni kell a profilaxisban részesülők arányát és el kell érni, hogy trombózisrizikó esetén a betegek megkapják a hatásos megelőzést. A beteg trombóziskockázatának felmérése fontos eszköze a vénás thromboembolia által veszélyeztetett betegek felderítésének, megkönnyíti a döntést a profilaxis elrendeléséről és javítja az irányelvi ajánlások betartását. A trombózisveszély megállapításakor, ha nem ellenjavallt, profilaxist kell alkalmazni. „A thromboemboliák kockázatának csökkentése és kezelése” című, 4. magyar antithromboticus irányelv felhívja a figyelmet a vénástrombózis-rizikó felmérésének szükségességére, és elsőként tartalmazza a kórházban fekvő belgyógyászati és sebészeti betegek kockázati kérdőívét. Ismertetjük a kockázatbecslő kérdőíveket és áttekintjük a kérdőívekben szereplő rizikófaktorokra vonatkozó bizonyítékokon alapuló adatokat.

Signature Analysis: Statistical Models and Their Application to FA

1996 ◽  
Author(s):  
C.K. Lakshminarayan ◽  
S. Pabbisetty ◽  
O. Adams ◽  
F. Pires ◽  
M. Thomas ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Failure Analysis ◽  
Statistical Models ◽  
Essential Elements ◽  
Assessment Model ◽  
Signature Analysis ◽  
Risk Assessment Model ◽  
Sample Sizes ◽  
Reliability Engineering ◽  
Semiconductor Chips

Abstract This paper deals with the basic concepts of Signature Analysis and the application of statistical models for its implementation. It develops a scheme for computing sample sizes when the failures are random. It also introduces statistical models that comprehend correlations among failures that fail due to the same failure mechanism. The idea of correlation is important because semiconductor chips are processed in batches. Also any risk assessment model should comprehend correlations over time. The statistical models developed will provide the required sample sizes for the Failure Analysis lab to state "We are A% confident that B% of future parts will fail due to the same signature." The paper provides tables and graphs for the evaluation of such a risk assessment. The implementation of Signature Analysis will achieve the dual objective of improved customer satisfaction and reduced cycle time. This paper will also highlight it's applicability as well as the essential elements that need to be in place for it to be effective. Different examples have been illustrated of how the concept is being used by Failure Analysis Operations (FA) and Customer Quality and Reliability Engineering groups.

A semi-quantitative risk assessment model for the outbreak of grass carp hemorrhage

2013 ◽  
Vol 19 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Song YANG ◽  
Shuqin WU ◽  
Ningqiu LI ◽  
Cunbin SHI ◽  
Guocheng DENG ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Grass Carp ◽  
Assessment Model ◽  
Quantitative Risk Assessment ◽  
Risk Assessment Model
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