Use of a systems-based approach to an environmental health assessment for a waterborne disease outbreak investigation at a snowmobile lodge in Wyoming.

Investigations into disease outbreaks generally incorporate an epidemiologic investigation, laboratory analysis, and an environmental health assessment. This last component is designed to discover connections between factors in the environment and the outbreak, but is often limited, either by time and resources, or the expertise of the personnel included in outbreak investigation teams. A waterborne Norovirus outbreak investigation in Sheridan County, Wyoming, in 2001 provides an excellent example of the importance of including an in-depth, systems-based environmental health assessment in outbreak investigations. The epidemiologic component of this investigation identified the water supply of a snowmobile lodge in the Bighorn Mountains as the source of the outbreak, a result that was confirmed by laboratory analysis. Including a systems-based environmental health assessment in this investigation also helped to uncover the underlying environmental factors that led to contamination of the water supply. Those factors included an onsite wastewater disposal system that was overloaded by increased use and not well suited to local soil and geologic conditions and a drinking water system with no treatment or disinfection. In addition, heavy precipitation and increased pumping of wells to satisfy higher demands probably facilitated the contamination of the drinking water wells by causing greater movement of wastewater through the soil and underlying bedrock. By focusing on these links between factors in the environment and adverse health outcomes, the systems-based environmental health assessment also helped to highlight prevention strategies for avoiding recurrences.

Responding to detection of aerosolized Bacillus anthracis by autonomous detection systems in the workplace.

Autonomous detection systems (ADSs) are under development to detect agents of biologic and chemical terror in the environment. These systems will eventually be able to detect biologic and chemical hazards reliably and provide approximate real-time alerts that an agent is present. One type of ADS that tests specifically for Bacillus anthracis is being deployed in hundreds of postal distribution centers across the United States. Identification of aerosolized B. anthracis spores in an air sample can facilitate prompt on-site decontamination of workers and subsequent administration of postexposure prophylaxis to prevent inhalational anthrax. Every employer who deploys an ADS should develop detailed plans for responding to a positive signal. Responding to ADS detection of B. anthracis involves coordinating responses with community partners and should include drills and exercises with these partners. This report provides guidelines in the following six areas: 1) response and consequence management planning, including the minimum components of a facility response plan; 2) immediate response and evacuation; 3) decontamination of potentially exposed workers to remove spores from clothing and skin and prevent introduction of B. anthracis into the worker's home and conveyances; 4) laboratory confirmation of an ADS signal; 5) steps for evaluating potentially contaminated environments; and 6) postexposure prophylaxis and follow-up.