Persistence of poliovirus types 2 and 3 in waste-impacted water and sediment.

Eradication of poliovirus (PV) is a global public health priority, and as clinical cases decrease, the role of environmental surveillance becomes more important. Persistence of PV and the environmental factors that influence it (such as temperature and sample type) are an important part of understanding and interpreting positive environmental surveillance samples. The objective of this study was to evaluate the persistence of poliovirus type 2 (PV2) and type 3 (PV3) in wastewater and sediment. Microcosms containing either 1) influent wastewater or 2) influent wastewater with a sediment matrix were seeded with either PV2 or PV3, and stored for up to 126 days at three temperatures (4°C, room temperature [RT], and 30°C). Active PV in the liquid of (1), and the sediment and liquid portions of (2) were sampled and quantified at up to 10 time points via plaque assay and RT-qPCR. A suite of 17 models were tested for best fit to characterize decay of PV2 and PV3 over time and determine the time points at which >90% (T90) and >99% (T99) reduction was reached. Linear models assessed the influence of experimental factors (matrix, temperature, virus type and method of detection) on the predicted T90 and T99 values. Results showed that when T90 was the dependent variable, virus type, matrix, and temperature significantly affected decay, and there was a clear interaction between the sediment matrix and temperature. When T99 was the dependent variable, only temperature and matrix type significantly influenced the decay metric. This study characterizes the persistence of both active and molecular PV2 and PV3 in relevant environmental conditions, and demonstrates that temperature and sediment both play important roles in PV viability. As eradication nears and clinical cases decrease, environmental surveillance and knowledge of PV persistence will play a key role in understanding the silent circulation in endemic countries.

Size-selective toxicity effects of the antimicrobial tylosin on estuarine phytoplankton communities.

The purpose of this study was to determine the lethal and sublethal effects of the antimicrobial tylosin on natural estuarine phytoplankton communities. Bioassays were used in experimental treatments with final concentrations of 5 to 1000 µg tylosin l(-1). Maximum percent inhibition ranged from 57 to 85% at concentrations of 200-400 µg tylosin l(-1). Half maximum inhibition concentrations of tylosin were ca. 5x lower for small phytoplankton (<20 µm) relative to larger phytoplankton (>20 µm) and suggests that small phytoplankton are more sensitive to tylosin exposure. Sublethal effects occurred at concentrations as low as 5 µg tylosin l(-1). Environmental concentrations of tylosin (e.g., 0.2-3 µg l(-1)) may have a significant sublethal effect that alters the size structure and composition of phytoplankton communities. The results of this study highlight the potential importance of cell size on toxicity responses of estuarine phytoplankton.

Economic Analysis of the Return-on-Investment of a Worksite Wellness Program for a Large Multistate Retail Grocery Organization.

OBJECTIVE: The objective of this study is to measure the return on investment (ROI) of the Price Chopper/Golub Corporation employee population who participate in wellness programs available to them. METHODS: Medical claims data, risk level, and presence of comorbidities such as diabetes and heart disease were compared in a matched retrospective cohort of participants and nonparticipants, with 2008, 2009, and 2010 serving as measurement years. Program costs and estimated savings were used to calculate an ROI of $4.33 for every dollar invested in wellness programs. RESULTS: Reductions in medical costs were observed at several risk and participation levels, with an average savings of $133 per participant and a 3-year savings estimate of $285,706. CONCLUSIONS: The positive ROI and savings estimate indicate that wellness interventions added economic value to Price Chopper/Golub Corporation.