No abstract

What is already known about this topic? Incorporating geographic information science and technology (GIS&T) into COVID-19 pandemic surveillance, modeling, and response enhances understanding and control of the disease. What is added by this report? Applications of GIS&T include developing spatial data infrastructures for surveillance and data sharing, incorporating mobility data in infectious disease forecasting, using geospatial technologies for digital contact tracing, integrating geographic data in COVID-19 modeling, investigating geographic social vulnerabilities and health disparities, and communicating the status of the disease or status of facilities for return-to-normal operations. What are the implications for public health practice? Protections for individual privacy and close collaboration among the fields of geography, medicine, public health, and public policy to use GIS&T are imperative.

Free-living protozoa have been implicated in the survival and transport of pathogens in the environment, but the relationship between non-Shiga toxin-producing Escherichia coli or Helicobacter pylori and ciliates has not been characterized. Six diarrheagenic pathotypes of E. coli and an isolate of H. pylori were evaluated for their susceptibility to digestion by Tetrahymena, an aquatic ciliate. Tetrahymena strain MB125 was fed E. coli or H. pylori, and the ciliate's egested products examined for viable bacterial pathogens by the BacLight(™) LIVE/DEAD (™) assay, a cell elongation method, and by colony counts. All six diarrheagenic E. coli pathotypes survived digestion, whereas H. pylori was digested. Growth of E. coli on agar plates indicated that the bacteria were able to replicate after passage through the ciliate. Transmission electron micrographs of E. coli cells as intact rods vs. degraded H. pylori cells corroborated these results. Scanning electron microscopy revealed a net-like matrix around intact E. coli cells in fecal pellets. These results suggest a possible role for Tetrahymena and its egested fecal pellets in the dissemination of diarrheagenic E. coli in the environment. This bacterial-protozoan interaction may increase opportunities for transmission of diarrheagenic E. coli to mammalian hosts including humans.

Mixing and aging are two related phenomena that affect the water quality changes that can occur within distribution system storage tanks and reservoirs. Long residence times depress disinfectant residuals and can promote bacterial regrowth, and uneven mixing can result in zones of older water. As a result, minimizing detention time and avoiding zones of water that remain in the storage facility for long periods of time should be implicit objectives in the design and operation of distribution system storage facilities. In this article, the authors present information and tools to assist water utilities in the design, retrofit, or operation of distribution system storage facilities so as to minimize the probability of seriously diminished water quality resulting from poor mixing and excessive aging.