Assessing Infection Control Measures for Pandemic Influenza

Wein, Lawrence M.; Atkinson, Michael P.

doi:10.1111/j.1539-6924.2009.01232.x

Cited by 39 publications

(39 citation statements)

References 47 publications

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“…The goal of this study was to obtain detailed quantitative information on fomite-to-finger transfer that could be used to model the probability of infection from exposure to various types of pathogens, a parameter needed for quantitative microbial risk assessments (1,5,48,49). Unfortunately, there are no standard methods for quantifying transfer rates, making it difficult to compare the results from various studies.…”

Section: Discussionmentioning

confidence: 99%

Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

Lopez

Gerba

Tamimi

et al. 2013

Appl Environ Microbiol

209

270

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Fomites can serve as routes of transmission for both enteric and respiratory pathogens. The present study examined the effect of low and high relative humidity on fomite-to-finger transfer efficiency of five model organisms from several common inanimate surfaces (fomites). Nine fomites representing porous and nonporous surfaces of different compositions were studied. Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, MS2 coliphage, and poliovirus 1 were placed on fomites in 10-l drops and allowed to dry for 30 min under low (15% to 32%) or high (40% to 65%) relative humidity. Fomite-to-finger transfers were performed using 1.0 kg/cm 2 of pressure for 10 s. Transfer efficiencies were greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer efficiencies under high relative humidity than under low relative humidity. Nonporous surfaces had a greater transfer efficiency (up to 57%) than porous surfaces (<6.8%) under low relative humidity, as well as under high relative humidity (nonporous, up to 79.5%; porous, <13.4%). Transfer efficiency also varied with fomite material and organism type. The data generated can be used in quantitative microbial risk assessment models to assess the risk of infection from fomite-transmitted human pathogens and the relative levels of exposure to different types of fomites and microorganisms. I nanimate objects, or fomites, are a potential reservoir in the transmission of pathogens either directly, by surface-to-mouth contact, or indirectly, by contamination of fingers and subsequent hand-to-mouth, hand-to-eye, or hand-to-nose contact (1-5). Bodily fluids such as saliva, mucus, nasal secretions, blood, urine, and feces may all potentially contain pathogens that can be transmitted via fomites (6-9). A number of studies have shown that enteric and respiratory pathogens are capable of surviving from hours to months on fomites, depending on the numbers deposited, the type of microorganism, and the variable environmental conditions (10-12). Several studies have shown that inanimate surfaces found in day care centers (8,(13)(14)(15)(16)(17), schools (18), office buildings (19), homes (20-27), public areas (28), or hospitals (12, 29-33) can be reservoirs for secondary modes of transmission, with contaminated hands playing a critical role as a route of exposure.The efficiency of transfer of a pathogen to the hand from the fomite is important in modeling the potential for its transmission (11,(34)(35)(36). This information can be used to understand the spread of disease in indoor environments and the potential for designing surfaces that reduce transfer efficiency and/or are antimicrobial (5). The purpose of this work was to better elucidate the transfer efficiencies of several different types of organisms under control conditions to provide data that may be used in quantitative microbial risk assessment (QMRA) models. (ii) Gram-negative and Gram-positive bacterial inoculum preparation. Frozen aliquots of E. coli an...

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Section: Discussionmentioning

confidence: 99%

Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

Lopez

Gerba

Tamimi

et al. 2013

Appl Environ Microbiol

209

270

View full text Add to dashboard Cite

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“…In the present study, we quantify the routes of transmission for influenza by formulating a detailed mathematical model of the viral shedding and transmission within a four-member household containing one infected, and using data from the literature to calibrate the model. In the companion paper (Wein and Atkinson, 2006), we embed the four-person household model from the present paper into an epidemic household model (Ball and Neal, 2002) in which between-household global contacts occur in addition to the within-household local contacts, and then assess various infection control measures, such as face protection, ventilation and humidifiers.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Routes of Transmission for Pandemic Influenza

2008

Self Cite

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Motivated by the desire to assess nonpharmaceutical interventions for pandemic influenza, we seek in this study to quantify the routes of transmission for this disease. We construct a mathematical model of aerosol (i.e., droplet-nuclei) and contact transmission of influenza within a household containing one infected. An analysis of this model in conjunction with influenza and rhinovirus data suggests that aerosol transmission is far more dominant than contact transmission for influenza. We also consider a separate model of a close expiratory event, and find that a close cough is unlikely ( approximately 1% probability) to generate traditional droplet transmission (i.e., direct deposition on the mucous membranes), although a close, unprotected and horizontally-directed sneeze is potent enough to cause droplet transmission. There are insufficient data on the frequency of close expiratory events to assess the relative importance of aerosol transmission and droplet transmission, and it is prudent to leave open the possibility that droplet transmission is important until proven otherwise. However, the rarity of close, unprotected and horizontally-directed sneezes-coupled with the evidence of significant aerosol and contact transmission for rhinovirus and our comparison of hazard rates for rhinovirus and influenza-leads us to suspect that aerosol transmission is the dominant mode of transmission for influenza.

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“…Transportation networks increase the spread of pathogens (DeHart, 2003;Khan et al, 2009) and populations exposed to public transportation are at an elevated risk of illness due to the higher probability of contact with pathogens (Freedman and Leder, 2005). Because influenza transmission occurs through touch, droplet and inhalation of aerosol particles, influenza is also transmissible within the confines of public transport cabins and passenger station platforms (Wein and Atkinson, 2009;Lindsley et al, 2010). However, little research has explored whether public transportation increases risk to illness from pandemic influenza.…”

Section: Introductionmentioning

confidence: 99%

Ecological factors associated with pandemic influenza A (H1N1) hospitalization rates in California, USA: a geospatial analysis

Maliszewski

Wei

2011

Geospat Health

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Abstract. The 2009 H1N1 influenza A virus subtype (H1N1) pandemic had a large impact in the United States of America (USA), causing an estimated 192,000 to 398,000 hospitalizations and 8,720 to 18,050 deaths between April 2009 and midMarch 2010. Recent research on the 2009 H1N1 pandemic has largely focused on individual, non-spatial demographic characterizations (e.g. age and race/ethnicity) associated with H1N1 hospitalizations. Broader ecological factors such as transportation use, land use and other socioeconomic factors are important aspects of influenza studies that have not been empirically examined. This research explores and identifies ecological factors associated with 2009 H1N1 pandemic hospitalization rates. We conducted a spatial regression analysis of county level hospitalization rates from 3 April to 15 September, 2009 obtained via the California Department of Public Health. Hospitalization rates were found to be spatially dependent. Public transportation usage rates and agricultural land use proportions were significant environmental factors positively related to hospitalization rates. Consistent with public health official's assumptions and existing evidence, county percentages of persons less than 18 years of age were positively associated with hospitalization. These findings help to clarify the limited consensus and dubious evidence on the role of broader ecological factors associated with pandemic influenza. A better understanding of the ecological risk factors associated with hospitalizations should also benefit public health officials with respect to their work aiming at improving emergency supply allocation and non-pharmaceutical intervention strategies in the context of an influenza pandemic.

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Assessing Infection Control Measures for Pandemic Influenza

Cited by 39 publications

References 47 publications

Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

Quantifying the Routes of Transmission for Pandemic Influenza

Ecological factors associated with pandemic influenza A (H1N1) hospitalization rates in California, USA: a geospatial analysis

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