Climate variability and change in the United States: Potential impacts on water- and foodborne diseases caused by microbiologic agents

Exposure to waterborne and foodborne pathogens can occur via drinking water (associated with fecal contamination), seafood (due to natural microbial h azards, toxins, or wastewater disposal) or fresh produce (irrigated or proc essed with contaminated water). Weather influences the transport and dissem ination of these microbial agents via rainfall and runoff and the survival and/or growth through such factors as temperature. Federal and state laws a nd regulatory programs protect much of the U.S. population from waterborne disease; however, if climate variability increases, current and future defi ciencies in areas such as watershed protection, infrastructure, and storm d rainage systems will probably increase the risk of contamination events. Kn owledge about transport processes and the fate of microbial pollutants asso ciated with rainfall and snowmelt is key to predicting risks from a change in weather variability. Although recent studies identified links between cl imate variability and occurrence of microbial agents in water, the relation ships need further quantification in the context of other stresses. In the marine environment as well, there are few studies that adequately address t he potential health effects of climate variability in combination with othe r stresses such as overfishing, introduced species, and rise in sea level. Advances in monitoring are necessary to enhance early-warning and preventio n capabilities. Application of existing technologies, such as molecular fin gerprinting to track contaminant sources or satellite remote sensing to det ect coastal algal blooms, could be expanded. This assessment recommends inc orporating a range of future scenarios of improvement plans for current def iciencies in the public health infrastructure to achieve more realistic ris k assessments.