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The validity of using indicator organisms (total and fecal coliforms, enterococci, Clostridium perfringens, and F-specific coliphages) to predict the presence or absence of pathogens (infectious enteric viruses, Cryptosporidium, and Giardia) was tested at six wastewater reclamation facilities. Multiple samplings conducted at each facility over a 1-year period. Larger sample volumes for indicators (0.2 to 0.4 liters) and pathogens (30 to 100 liters) resulted in more sensitive detection limits than are typical of routine monitoring. Microorganisms were detected in disinfected effluent samples at the following frequencies: total coliforms, 63%; fecal coliforms, 27%; enterococci, 27%; C. perfringens, 61%; F-specific coliphages, approximately 40%; and enteric viruses, 31%. Cryptosporidium oocysts and Giardia cysts were detected in 70% and 80%, respectively, of reclaimed water samples. Viable Cryptosporidium, based on cell culture infectivity assays, was detected in 20% of the reclaimed water samples. No strong correlation was found for any indicator-pathogen combination. When data for all indicators were tested using discriminant analysis, the presence/absence patterns for Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and infectious enteric viruses were predicted for over 71% of disinfected effluents. The failure of measurements of single indicator organism to correlate with pathogens suggests that public health is not adequately protected by simple monitoring schemes based on detection of a single indicator, particularly at the detection limits routinely employed. Monitoring a suite of indicator organisms in reclaimed effluent is more likely to be predictive of the presence of certain pathogens, and a need for additional pathogen monitoring in reclaimed water in order to protect public health is suggested by this study.

The development of disease-modifying treatments for Alzheimer's disease (AD) faces a number of barriers. Among these are the lack of surrogate biomarkers, the exceptional size and duration of clinical trials, difficulties in identifying appropriate populations for clinical trials, and the limitations of monotherapies in addressing such a complex multifactorial disease. This study sets out to first estimate the consequent impact on the expected cost of developing disease-modifying treatments for AD and then to estimate the potential benefits of bringing together industry, academic, and government stakeholders to co-invest in, for example, developing better biomarkers and cognitive assessment tools, building out advanced registries and clinical trial-readiness cohorts, and establishing clinical trial platforms to investigate combinations of candidate drugs and biomarkers from the portfolios ofmultiple companies. Estimates based on interviews with experts on AD research and development suggest that the cost of one new drug is now $5.7 billion (95% confidence interval (CI) $3.7-9.5 billion) and could be reduced to $2.0 billion (95% CI $1.5-2.9 billion). The associated acceleration in the arrival of disease-modifying treatments could reduce the number of case years of dementia by 7.0 million (95% CI 4.4-9.4 million) in the United States from 2025 through 2040. [ABSTRACT FROM AUTHOR]

Several genotypic and phenotypic microbial source tracking (MST) methods have been proposed and utilized to differentiate groups of microorganisms, usually indicator organisms, for the purpose of tracking sources of fecal pollution. Targeting of host-specific microorganisms is one of the approaches currently being tested. These methods are useful as they circumvent the need to isolate individual microorganisms and do not require the establishment of reference databases. Several studies have demonstrated that the presence and distribution of Enterococcus spp. in feces seems to be influenced by the host species. Here, we present a method for detection of genetic sequences in culturable enterococci capable of identifying human sources of fecal pollution in the environment. The human fecal pollution marker designed in this study targets a putative virulence factor, the enterococcal surface protein (esp), in Enterococcus faecium. This gene was detected in 97% of sewage and septic samples but was not detected in any livestock waste lagoons or in bird or animal fecal samples. Epidemiological studies in recreational and groundwaters have shown enterococci to be useful indicators of public health risk for gastroenteritis. By identifying the presence of human fecal pollution, and therefore the possible presence of human enteric pathogens, this marker allows for further resolution of the source of this risk. [ABSTRACT FROM AUTHOR]