An overview of US cryptosporidiosis outbreaks suggests that conventional treatment processes operated at minimum regulatory compliance levels are ineffective at preventing transmission of the disease. Drinking water has been implicated as the mode of transmission in several outbreaks of cryptosporidiosis throughout the United States. This review of US outbreaks describes characteristics of the raw water supply, suspected sources of contamination, water treatment methods, and corrective actions. Of the total number of outbreaks, roughly half were associated with groundwater sources; the majority of affected individuals, however, were served by drinking water drawn from surface water. Wastewater was implicated as the source of contamination of raw or treated water for roughly half of the outbreaks. Nonpoint sources, such as agricultural runoff, were suspected sources of contamination in the remaining outbreaks. The majority of affected individuals were served by treatment plants using coagulant addition, filtration, and chlorine disinfection processes. Although treatment deficiencies and suboptimal operational practices were noted during some of the outbreaks, all treatment plants were complying with federal and local regulations. Existing regulations and water supply systems, especially those utilizing surface water sources, should be reevaluated.
During June 1996, water supplies of the city of San Pedro Sula, Honduras, were sampled to obtain an assessment of Cryptosporidium oocyst and Giardia cyst concentrations. Each sample was concentrated and stained with an indirect immunofluorescent antibody, and parasites were counted through microscopic analysis. In three surface water supplies, Cryptosporidium oocyst concentrations ranged from 58 to 260 oocysts per 100 L, and Giardia cysts were present in concentrations ranging from 380 to 2100 cysts per 100 L. Unlike the surface water samples, groundwater had a higher concentration of Cryptosporidium oocysts (26/100 L) than Giardia cysts (6/100 L), suggesting that the groundwater aquifer protects the water supply more effectively from larger Giardia cysts. Cryptosporidium oocyst concentrations are within the typical range for surface water supplies in North America whereas Giardia cyst concentrations are elevated. Efforts should be made to protect raw water from sources of contamination.
The Strategic National Stockpile (SNS) serves as a repository of materiel, including medical countermeasures (MCMs), that would be used to support the national health security response to a chemical, biological, radiological, or nuclear (CBRN) incident, either natural or terrorism-related. To support and advance the SNS, the National Institutes of Health (NIH) manages targeted investigatory research portfolios, such as Countermeasures Against Chemical Terrorism (CounterACT) for chemical agents, that coordinate projects covering basic research, drug discovery, and preclinical studies. Project BioShield, managed by the Biomedical Advanced Research and Development Agency (BARDA), guides and supports academia and industry with potential MCMs through the Food & Drug Administration's approval process and ultimately supports the acquisition of successful products into the SNS. Public health emergencies such as the COVID-19 pandemic and the ever-increasing number of MCMs in the SNS present logistical and financial challenges to its maintenance. While MCMs for biological agents have been readily adopted, those for chemical agents have required sustained investments. This paper reviews the methods by which MCMs are identified and supported for inclusion in the SNS, the current status of MCMs for CBRN threats, and challenges with SNS maintenance as well as identifies persistent obstacles for MCM development and acquisition, particularly for ones focused on chemical weapons.
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