"Back to the Future": Time for a Renaissance of Public Health Engineering.

Public health has always been, and remains, an interdisciplinary field, and engineering was closely aligned with public health for many years. Indeed, the branch of engineering that has been known at various times as sanitary engineering, public health engineering, or environmental engineering was integral to the emergence of public health as a distinct discipline. However, in the United States (U.S.) during the 20th century, the academic preparation and practice of this branch of engineering became largely separated from public health. Various factors contributed to this separation, including an evolution in leadership roles within public health; increasing specialization within public health; and the emerging environmental movement, which led to the creation of the U.S. Environmental Protection Agency (EPA), with its emphasis on the natural environment. In this paper, we consider these factors in turn. We also present a case study example of public health engineering in current practice in the U.S. that has had large-scale positive health impacts through improving water and sanitation services in Native American and Alaska Native communities. We also consider briefly how to educate engineers to work in public health in the modern world, and the benefits and challenges associated with that process. We close by discussing the global implications of public health engineering and the need to re-integrate engineering into public health practice and strengthen the connection between the two fields.

A systems analysis of irrigation water quality in an environmental assessment of an E. coli O157:H7 outbreak in the United States linked to iceberg lettuce.

A foodborne Escherichia coli O157:H7 outbreak in December 2006 included 77 illnesses reported in Iowa and Minnesota. Epidemiologic investigations by health departments in those states and the U.S. Centers for Disease Control and Prevention (CDC) identified shredded iceberg lettuce (Lactuca sativa L.) as the vehicle of transmission. The U.S. Food and Drug Administration (FDA) and Minnesota and California public health agencies traced the lettuce to several growing regions in California based on information from a lettuce processor in Minnesota. Samples from an environmental investigation initiated by the California Food Emergency Response Team (CalFERT) revealed a genetic match between the outbreak strain and environmental samples from a single farm, leading to an in-depth systems-based analysis of the irrigation water system on that farm. This paper presents findings from that systems-based analysis, which assessed conditions on the farm potentially contributing to contamination of the lettuce. The farm had three sources of irrigation water: groundwater from onsite wells, surface water delivered by a water management agency and effluent from wastewater lagoons on nearby dairy farms. Wastewater effluent was blended with the other sources and used only to irrigate animal feed crops. However, water management on the farm, including control of wastewater blending, appeared to create potential for cross-contamination. Pressure gradients and lack of backflow measures in the irrigation system might have created conditions for cross-contamination of water used to irrigate lettuce. The irrigation network on the farm had evolved over time to meet various needs, without an overall analysis of how that evolution potentially created vulnerabilities to contamination of irrigation water. The type of systems analysis described here is one method for helping to ensure that such vulnerabilities are identified and addressed. A preventive, risk-based management approach, such as the Water Safety Plan process for drinking water, may also be useful in managing irrigation water quality.

Sustainability of water, sanitation and hygiene interventions in Central America.

The American Red Cross and U.S. Centers for Disease Control and Prevention collaborated on a sustainability evaluation of post-hurricane water, sanitation and hygiene (WASH) interventions in Central America. In 2006 and 2009, we revisited six study areas in rural El Salvador, Guatemala, Honduras and Nicaragua to assess sustainability of WASH interventions finalized in 2002, after 1998's Hurricane Mitch. We used surveys to collect data, calculate indicators and identify factors that influence sustainability. Regional sustainability indicator results showed there was a statistically significant decline in access to water. The presence of sanitation facilities had not changed since the beginning of the project; however, maintenance and use of latrines declined but continued to meet the goal of 75% use after 7 years. The hygiene indicator, hand washing, initially declined and then increased. Declines in water access were due to operational problems related to storm events and population changes. Sanitation facilities were still present and sometimes used even though they reached or surpassed their original design life. Changes in hygiene practices appeared related to ongoing hygiene promotion from outside organizations. These results provide useful input for making WASH programs more sustainable and informing future, more in-depth research into factors influencing sustainability.

Development of indicators for measuring outcomes of water safety plans.

Water safety plans (WSPs) are endorsed by the World Health Organization as the most effective method of protecting a water supply. With the increase in WSPs worldwide, several valuable resources have been developed to assist practitioners in the implementation of WSPs, yet there is still a need for a practical and standardized method of evaluating WSP effectiveness. In 2012, the Centers for Disease Control and Prevention (CDC) published a conceptual framework for the evaluation of WSPs, presenting four key outcomes of the WSP process: institutional, operational, financial and policy change. In this paper, we seek to operationalize this conceptual framework by providing a set of simple and practical indicators for assessing WSP outcomes. Using CDC's WSP framework as a foundation and incorporating various existing performance monitoring indicators for water utilities, we developed a set of approximately 25 indicators of institutional, operational, financial and policy change within the WSP context. These outcome indicators hold great potential for the continued implementation and expansion of WSPs worldwide. Having a defined framework for evaluating a WSP's effectiveness, along with a set of measurable indicators by which to carry out that evaluation, will help implementers assess key WSP outcomes internally, as well as benchmark their progress against other WSPs in their region and globally.

Development of Haiti's rural water, sanitation and hygiene workforce.

In 2009 the Haitian Directorate of Potable Water and Sanitation (DINEPA) identified an inadequately trained and under-staffed rural workforce as one of their main institutional challenges. Plans to address this challenge were impacted by the devastating earthquake of January 12, 2010 and the cholera outbreak of October 2010, both of which further complicated Haiti's already poor water and sanitation conditions. Recognizing the importance of DINEPA's institutional priorities, donor and technical assistance groups provided needed support to improve the country's conditions and build the rural water and sanitation workforce. This report describes how DINEPA and the US Centers for Disease Control and Prevention (CDC) collaborated to design and implement a training program for 264 potable water and sanitation technicians for rural areas. The paper also describes the initial field activities of the newly trained technicians and the immediate impact of their work in the rural water, sanitation and hygiene sector.

A conceptual framework to evaluate the outcomes and impacts of water safety plans.

A Water Safety Plan (WSP) is a preventive, risk management approach to ensure drinking water safety. The World Health Organization (WHO) guidelines place WSPs within a larger 'framework for safe drinking-water' that links WSPs to health, creating an implicit expectation that implementation of WSPs will safeguard health in areas with acceptable drinking water quality. However, many intervening factors can come between implementation of an individual WSP and ultimate health outcomes. Evaluating the impacts of a WSP, therefore, requires a much broader analysis than simply looking at health improvements. Until recently, little guidance for the monitoring and evaluation of WSPs existed. Drawing examples from existing WSPs in various regions, this paper outlines a conceptual framework for conducting an overall evaluation of the various outcomes and impacts of a WSP. This framework can provide a common basis for implementers to objectively monitor and evaluate the range of outcomes and impacts from WSPs, as well as a common understanding of the time frames within which those results may occur. As implementers understand the various outcomes and impacts of WSPs beyond health, a strong evidence base for the effectiveness of WSPs will develop, further enabling the scaling up of WSP implementation and provision of better quality water.

Health impact of water and sanitation infrastructure reconstruction programmes in eight Central American communities affected by Hurricane Mitch.

In response to Hurricane Mitch, which struck Central America in October-November 1998, the American Red Cross (ARC) and the Centers for Disease Control and Prevention (CDC) collaborated on a 3-year evaluation of the public health impact of ARC's water, sanitation and hygiene education activities in eight study areas in Honduras, Nicaragua, El Salvador and Guatemala. The evaluation compared: 1) access to and use of water and sanitation facilities, 2) the use of hygienic behaviours, and 3) diarrhoeal prevalence in children younger than 3 years of age before (February 2000) and after (February 2002) the interventions had been implemented. The evaluation included household and key informant interviews designed to measure these three components. Water quality of community water sources and household water was evaluated by measuring levels of indicator bacteria. During the final survey, an infrastructure evaluation provided a review of the design, construction, and current operation and maintenance of the water systems and latrines. The integrated water and sanitation infrastructure interventions and hygiene education programmes implemented following Hurricane Mitch effectively decreased diarrhoea prevalence in the target communities.

Surveillance for waterborne disease and outbreaks associated with drinking water and water not intended for drinking--United States, 2003-2004.

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists have maintained a collaborative Waterborne Disease and Outbreaks Surveillance System for collecting and reporting data related to occurrences and causes of waterborne disease and outbreaks (WBDOs). This surveillance system is the primary source of data concerning the scope and effects of WBDOs in the United States. REPORTING PERIOD: Data presented summarize 36 WBDOs that occurred during January 2003-December 2004 and nine previously unreported WBDOs that occurred during 1982-2002. DESCRIPTION OF SYSTEM: The surveillance system includes data on WBDOs associated with drinking water, water not intended for drinking (excluding recreational water), and water of unknown intent. Public health departments in the states, territories, localities, and Freely Associated States (i.e., the Republic of the Marshall Islands, the Federated States of Micronesia, and the Republic of Palau, formerly parts of the U.S.-administered Trust Territory of the Pacific Islands) are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC by using a standard form. RESULTS: During 2003-2004, a total of 36 WBDOs were reported by 19 states; 30 were associated with drinking water, three were associated with water not intended for drinking, and three were associated with water of unknown intent. The 30 drinking water-associated WBDOs caused illness among an estimated 2,760 persons and were linked to four deaths. Etiologic agents were identified in 25 (83.3%) of these WBDOs: 17 (68.0%) involved pathogens (i.e., 13 bacterial, one parasitic, one viral, one mixed bacterial/parasitic, and one mixed bacterial/parasitic/viral), and eight (32.0%) involved chemical/toxin poisonings. Gastroenteritis represented 67.7% of the illness related to drinking water-associated WBDOs; acute respiratory illness represented 25.8%, and dermatitis represented 6.5%. The classification of deficiencies contributing to WBDOs has been revised to reflect the categories of concerns associated with contamination at or in the source water, treatment facility, or distribution system (SWTD) that are under the jurisdiction of water utilities, versus those at points not under the jurisdiction of a water utility or at the point of water use (NWU/POU), which includes commercially bottled water. A total of 33 deficiencies were cited in the 30 WBDOs associated with drinking water: 17 (51.5%) NWU/POU, 14 (42.4%) SWTD, and two (6.1%) unknown. The most frequently cited NWU/POU deficiencies involved Legionella spp. in the drinking water system (n = eight [47.1%]). The most frequently cited SWTD deficiencies were associated with distribution system contamination (n = six [42.9%]). Contaminated ground water was a contributing factor in seven times as many WBDOs (n = seven) as contaminated surface water (n = one). INTERPRETATION: Approximately half (51.5%) of the drinking water deficiencies occurred outside the jurisdiction of a water utility in situations not currently regulated by EPA. The majority of the WBDOs in which deficiencies were not regulated by EPA were associated with Legionella spp. or chemicals/toxins. Problems in the distribution system were the most commonly identified deficiencies under the jurisdiction of a water utility, underscoring the importance of preventing contamination after water treatment. The substantial proportion of WBDOs involving contaminated ground water provides support for the Ground Water Rule (finalized in October 2006), which specifies when corrective action is required for public ground water systems. PUBLIC HEALTH ACTIONS: CDC and EPA use surveillance data to identify the types of water systems, deficiencies, and etiologic agents associated with WBDOs and to evaluate the adequacy of current technologies and practices for providing safe drinking water. Surveillance data also are used to establish research priorities, which can lead to improved water-quality regulation development. The growing proportion of drinking water deficiencies that are not addressed by current EPA rules emphasizes the need to address risk factors for water contamination in the distribution system and at points not under the jurisdiction of water utilities.