Disinfection of Ebola Virus in Sterilized Municipal Wastewater

Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification

Resources, Capabilities, and Routines in Public Organizations

States, state agencies, multilateral agencies, and other non-market actors are relatively under-studied in strategic management and organization science. While important contributions to the study of public actors have been made within the agency-theoretic and transaction-cost traditions, there is little research in political economy that builds on resource-based, dynamic capabilities, and behavioral approaches to the firm. Yet public organizations can be characterized as stocks of human and non-human resources, including routines and capabilities; they can possess excess capacity in these resources; and they may grow and diversify in predictable patterns according to behavioral and Penrosean logic. This paper shows how resource-based, dynamic capabilities, and behavioral approaches to understanding public agencies and organizations shed light on their nature and governance

Persistence of Ebola Virus in Sterilized Wastewater

In the wake of the ongoing 2014/2015 Ebola virus outbreak, significant questions regarding the appropriate handling of Ebola virus-contaminated liquid waste remain, including the persistence of Ebola virus in wastewater. To address these uncertainties, we evaluated the persistence of Ebola virus spiked in sterilized domestic sewage. The viral titer decreased approximately 99% within the first test day from an initial viral titer of 10⁶ TCID₅₀ mL^–1; however, it could not be determined if this initial rapid decrease was due to aggregation or inactivation of the viral particles. The subsequent viral titer decrease was less rapid, and infectious Ebola virus particles persisted for all 8 days of the test. The inactivation constant (<i>k</i>) was determined to be −1.08 (2.1 days for a 90% viral titer decrease). Due to experimental conditions, we believe these results to be an upper bound for Ebola virus persistence in wastewater. Wastewater composition is inherently heterogeneous; subsequently, we caution that interpretation of these results should be made within a holistic assessment, including the effects of wastewater composition, dilution, and potential exposure routes within wastewater infrastructure. While it remains unknown if Ebola virus may be transmitted via wastewater, these data demonstrate a potential exposure route to infectious Ebola virus via wastewater and emphasize the value of a precautionary approach to wastewater handling in an epidemic response

Log viral removal versus estimated Ct.

<p>Viral removal for 5 and 10 mg L^-1 chlorine conditions shown at detection limit for demonstration purposes. Dashed line represents limit of detection. The limit of detection was 0.75 log TCID₅₀ mL^-1, resulting in a maximum observable log₁₀ TCID₅₀ removal of 4.18 TCID₅₀ mL^-1.</p

Disinfection of Ebola virus at 0 and 1 mg/L added chlorine.

<p>No virus was recovered from the 5 and 10 mg/L chlorine conditions at any time point. The limit of detection was 0.75 log TCID₅₀/mL. Error bars represent one standard deviation.</p

Ebola virus persistence in wastewater at neutral (6.9), acidic (4.3), and basic (11.2) pH.

<p>The limit of detection was 0.75 log TCID₅₀ mL^-1. Error bars represent one standard deviation.</p

Free chlorine concentration in sterilized (gamma-irradiated) wastewater (A) and wastewater (B) over four time points (2, 10, 20 and 60 minutes) for initial doses of 0, 1, 5, and 10 mgL^-1 sodium hypochlorite.

<p>Error bars represent the standard deviation calculated from three replicates.</p

Composition of gamma irradiated wastewater.

<p>Values in brackets indicate 95% confidence interval.</p