Contamination of drinking water by microbial pathogens, chemical compounds, or radiologic agents has the potential to affect the health of millions of Americans and may lead to severe morbidity and mortality in vulnerable populations. Prevention of waterborne disease and its ill-effects is vital to our nation's well-being. Access to safe drinking water is a cornerstone of public health. It is important to note that the advent of childhood vaccinations, modern sanitation methods, and access to potable water have increased the lifespan and improved the general health of U.S. citizens more than any other advances in the field of medicine to date.
The medical community will continue to play a critical role in protecting the public's health through the recognition, management, and prevention of water-related disease in their patients and communities. The events of September 11 have added a new dimension to this public health challenge and have emphasized the need for medical practitioners to recognize unusual waterborne disease trends that may result from intentional contamination of water with biological, chemical, or radiologic agents. Medical practitioners throughout the United States must understand that they are likely to be the first to observe the early warning signs and changes in illness patterns that may result from intentional contamination of water, and that they may be the "front-line responders" in detecting acts of water terrorism.
The timely detection and treatment of waterborne disease are essential because the medical, public health, and economic consequences of a water contamination could be grave. The massive outbreak of waterborne cryptosporidiosis in Milwaukee in 1993 is an example of how contaminated water distributed through a municipal water system can lead to a major public health crisis. As a result of the contamination, an estimated 403,000 Milwaukee residents, or 52% of the population, developed diarrhea. More than 4000 persons required hospitalization. Cryptosporidiosis was listed as the underlying or contributing cause of death in 54 residents following the outbreak; susceptible populations were most severely affected. An estimated 725,000 productive days were lost, costing more than $54 million in lost work time and additional expenses to residents and local government.
In 2000, the water supply of Walkerton, Ontario, a small, rural community, was contaminated with Escherichia coli O157:H7. A total of 2300 residents experienced symptoms, and 7 people died. Reconstructing the community's potable water supply and installing temporary filtration cost more than $11 million. The estimated total cost of this event was $155 million by 2001.
Recognizing waterborne disease resulting from natural, accidental or intentional contamination of water suppliesis a diagnostic challenge for most practicing physicians in the United States for several reasons, including:
Patients may not be aware of exposure to waterborne biological, chemical, or radiologic agents, and obtaining an accurate exposure history is often difficult.
Many of the signs and symptoms of waterborne disease and the health effects of water contamination are nonspecific and often mimic more common medical disorders.
Co-infection with multiple waterborne pathogens or exposure to a mixture of chemical agents is common in persons exposed to waterborne contaminants, making accurate diagnosis difficult.
Exposure to waterborne toxins in a healthy patient population may manifest as benign symptoms or self-limited illness, while the same exposure in a vulnerable population may result in significant morbidity and mortality.
Public drinking water may represent only 1 source of contamination; other sources must also be investigated, including recreational waters, swimming pools, water parks, medical and dental devices, and commercial bottled water.
Many infectious pathogens and chemical contaminants are not unique to water, and other sources of contamination in the patient's environment, such as food, soil, and air, must also be ruled out.
Accurate and timely diagnosis of water-related disease by the medical community is a critical element in any successful strategy to protect water quality and security and ultimately the public's health. As mentioned, there are many barriers to detecting and accurately diagnosing waterborne disease and the health effects of water contamination. Understanding the following subject areas will provide the key elements necessary for healthcare providers to improve their clinical knowledge of water-related disease and to enhance their awareness of water-quality issues in their community.
Basic understanding of waterborne disease trends and exposure pathways. For healthcare providers to accurately diagnose water-related disease, they must acquire a basic understanding of waterborne disease trends, major causes of water pollution, and subsequent routes of transmission. They must also know the sources of exposure to water contaminants to be able to take an effective exposure history and make an accurate diagnosis.
Evaluation and management of water-related disease resulting from biological, chemical, and radiologic contaminants. Healthcare providers should possess a working knowledge of the symptomatology of water-related disease, appropriate diagnostic laboratory testing, disease-specific clinical management guidelines, and public health reporting requirements for the most common infectious waterborne pathogens, chemical compounds, and radiologic agents encountered in the United States.
Evaluation and management of water-related disease in susceptible populations. All healthcare providers must recognize the special health needs of sensitive populations at greatest risk for morbidity and mortality. These groups include pregnant women and developing fetuses; neonates, infants, and children; geriatric patients, including nursing home residents; immunosuppressed individuals, including patients with HIV and AIDS; those undergoing immunosuppressive therapy, including organ transplantation and chemotherapy; and patients with preexisting clinical disorders or chronic diseases causing impairment of the renal, hepatic, or immunologic system.
Two free Web-based clinical resource guides and disaster-response tools have been developed for the medical community that address all aspects of the evaluation and management of water-related disease resulting from both accidental and intentional water contamination. The goal of these guides is to streamline access to resources for the medical and public health communities that will help them to recognize, manage, and prevent water-related disease.