Browsing by Author "Harwood, Valerie"
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- Microbes in Beach Sands: Integrating Environment, Ecology and Public HealthPublication . Whitman, Richard; Harwood, Valerie; Edge, Thomas; Nevers, Meredith; Byappanahalli, Muruleedhara; Vijayavel, Kannappan; Brandão, João; Sadowsky, Michael; Wheeler Alm, Elizabeth; Crowe, Allan; Ferguson, Donna; Ge, Zhongfu; Halliday, Elizabeth; Kinzelman, Julie; Kleinheinz, Greg; Przybyla-Kelly, Kasia; Staley, Christopher; Staley, Zachery; Solo-Gabriele, HelenaBeach sand is a habitat that supports many microbes, including viruses, bacteria, fungi and protozoa (micropsammon). The apparently inhospitable conditions of beach sand environments belie the thriving communities found there. Physical factors, such as water availability and protection from insolation; biological factors, such as competition, predation, and biofilm formation; and nutrient availability all contribute to the characteristics of the micropsammon. Sand microbial communities include autochthonous species/phylotypes indigenous to the environment. Allochthonous microbes, including fecal indicator bacteria (FIB) and waterborne pathogens, are deposited via waves, runoff, air, or animals. The fate of these microbes ranges from death, to transient persistence and/or replication, to establishment of thriving populations (naturalization) and integration in the autochthonous community. Transport of the micropsammon within the habitat occurs both horizontally across the beach, and vertically from the sand surface and ground water table, as well as at various scales including interstitial flow within sand pores, sediment transport for particle-associated microbes, and the large-scale processes of wave action and terrestrial runoff. The concept of beach sand as a microbial habitat and reservoir of FIB and pathogens has begun to influence our thinking about human health effects associated with sand exposure and recreational water use. A variety of pathogens have been reported from beach sands, and recent epidemiology studies have found some evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB and enteric pathogens have consequences for watershed/beach management strategies and regulatory standards for safe beaches. This review summarizes our understanding of the community structure, ecology, fate, transport, and public health implications of microbes in beach sand. It concludes with recommendations for future work in this vastly under-studied area.
- Minimizing Errors in RT-PCR Detection and Quantification of SARS-CoV-2 RNA for Wastewater SurveillancePublication . Ahmed, Warish; Simpson, Stuart; Bertsch, Paul; Bibby, Kyle; Bivins, Aaron; Blackall, Linda; Bofill-Mas, Silvia; Bosch, Albert; Brandao, Joao; Choi, Phil; Ciesielski, Mark; Donner, Erica; D'Souza, Nishita; Farnleitner, Andreas; Gerrity, Daniel; Gonzalez, Raul; Griffith, John; Gyawali, Pradip; Haas, Charles; Hamilton, Kerry; Hapuarachchi, Chanditha; Harwood, Valerie; Haque, Rehnuma; Jackson, Greg; Khan, Stuart; Khan, Wesaal; Kitajima, Masaaki; Korajkic, Asja; La Rosa, Giuseppina; Layton, Blythe; Lipp, Erin; McLellan, Sandra; McMinn, Brian; Medema, Gertjan; Metcalfe, Suzanne; Meijer, Wim; Mueller, Jochen; Murphy, Heather; Naughton, Colleen; Noble, Rachel; Payyappat, Sudhi; Petterson, Susan; Pitkanen, Tarja; Rajal, Veronica; Reyneke, Brandon; Roman, Fernando; Rose, Joan; Rusinol, Marta; Sadowsky, Michael; Sala-Comorera, Laura; Setoh, Yin Xiang; Sherchan, Samendra; Sirikanchana, Kwanrawee; Smith, Wendy; Steele, Joshua; Sabburg, Rosalie; Symonds, Erin; Thai, Phong; Thomas, Kevin; Tynan, Josh; Toze, Simon; Thompson, Janelle; Whiteley, Andy; Wong, Judith; Sano, Daisuke; Wuertz, Stefan; Xagoraraki, Irene; Zhang, Qian; Zimmer-Faust, Amity; Shanks, OrinWastewater surveillance for pathogens using the reverse transcription-polymerase chain reaction (RT-PCR) is an effective, resource-efficient tool for gathering additional community-level public health information, including the incidence and/or prevalence and trends of coronavirus disease-19 (COVID-19). Surveillance of SARS-CoV-2 in wastewater may provide an early-warning signal of COVID-19 infections in a community. The capacity of the world’s environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is rapidly increasing. However, there are no standardized protocols nor harmonized quality assurance and quality control (QA/QC) procedures for SARS-CoV-2 wastewater surveillance. This paper is a technical review of factors that can lead to false-positive and -negative errors in the surveillance of SARS-CoV-2, culminating in recommendations and strategies that can be implemented to identify and mitigate these errors. Recommendations include, stringent QA/QC measures, representative sampling approaches, effective virus concentration and efficient RNA extraction, amplification inhibition assessment, inclusion of sample processing controls, and considerations for RT-PCR assay selection and data interpretation. Clear data interpretation guidelines (e.g., determination of positive and negative samples) are critical, particularly during a low incidence of SARS-CoV-2 in wastewater. Corrective and confirmatory actions must be in place for inconclusive and/or potentially significant results (e.g., initial onset or reemergence of COVID-19 in a community). It will also be prudent to perform inter-laboratory comparisons to ensure results are reliable and interpretable for ongoing and retrospective analyses. The strategies that are recommended in this review aim to improve SARS-CoV-2 characterization for wastewater surveillance applications. A silver lining of the COVID-19 pandemic is that the efficacy of wastewater surveillance was demonstrated during this global crisis. In the future, wastewater will play an important role in the surveillance of a range of other communicable diseases.