Is Waterborne Disease Still an Issue in the United States?

Michael Beach, PhD


October 22, 2012

Editorial Collaboration

Medscape &

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Hello. I am Michael Beach, Chief of the Waterborne Disease Prevention Branch at CDC. In 1908, the first US drinking water plant implemented chlorination of water to protect community health. Over the next decade, thousands of cities across the United States followed suit, contributing to a dramatic decrease in waterborne diseases such as typhoid fever, which had a 1000-fold reduction in incidence over the past century, making drinking water treatment one of the great public health achievements of the 20th century. Today I want to raise awareness that, despite these improvements, waterborne disease in the United States is still a part of everyday life. The widespread use of water in the United States has resulted in a broad array of pathogen- and chemical-related waterborne disease issues. I would like to talk about 4 critical areas: drinking water, recreational water, the built environment, and climate change.

Drinking water. Our water systems were built by our parents and grandparents, but we have not continued to invest in system upgrades and pipe replacements. As a result, we have an estimated 240,000 water main breaks yearly that could potentially expose users to sewage, pathogens, and other contaminants. Also, more than 15 million households get their water from private wells, which are not regulated by public health officials. This requires homeowners to take on responsibility for their water quality, which limited studies indicate is not what it should be. Most people have no clue and don't realize that they should, at a minimum, be doing annual water testing. Clinicians should consider a patient's water source as part of their evaluation, particularly in rural areas, where agricultural and animal runoff may affect water quality.

Recreational water use. Leisure time has increased, resulting in hundreds of millions of swimming visits each year to the ocean, lakes, and swimming pools. In fact, the largest number of waterborne outbreaks now reported to CDC are associated with swimming. The emergence of the chlorine-tolerant parasite Cryptosporidium -- the top cause of swimming pool-associated outbreaks in the United States -- has affected both drinking water systems and swimming pools because it can bypass our traditional safety net, chlorination. Clinicians should advise patients not to swallow recreational water and to refrain from swimming when they have diarrhea and, if diagnosed with cryptosporidiosis, for 2 weeks after cessation of symptoms.

Built environment. We have created a built environment of buildings, homes, and industries that are associated with miles of pipe and warm water -- ideal growth environments for biofilms, that scum layer in pipes and places where water is continually present. Biofilms have a well-documented association with pathogens. These biofilm habitats have been exploited by environmental pathogens such as Pseudomonas, Legionella, nontuberculous mycobacteria, and Acanthamoeba. This underscores how waterborne disease has expanded from the classic transmission route of drinking contaminated water to include other routes of transmission such as direct contact and inhalation of aerosols created by water system components such as shower heads, hot water taps, and building cooling systems. Clinicians should be aware that advanced age, immunocompromising conditions, underlying lung disease, and a history of smoking increase risk for infection with Legionella and other respiratory pathogens commonly found in building water systems.

Climate change. Climate change is already creating water issues around the globe via droughts, floods, and increasing water temperatures. Naegleria fowleri is a climate-sensitive, hot water-loving ameba found in freshwater lakes and hot springs that causes primary amebic meningoencephalitis (PAM), an almost universally fatal disease. Naegleria migrates up the nose to the brain and has caused more than 120 cases of PAM in southern-tier states since 1962. Over the past 2 years, we have seen Naegleria's geographic range expanding northward, with the first cases documented in Minnesota and Kansas, and the first case in Virginia since 1969. CDC just published an investigation[1] showing, for the first time, that Naegleria fowleri could be found in the hot water system biofilm of residential plumbing and caused the deaths of 2 people in Louisiana. Both individuals were regular users of neti pots for sinus irrigation and apparently made their irrigation solutions with Naegleria fowleri-contaminated household tap water. All patients should understand that tap water from any source is not sterile. Clinicians should recommend that people using nasal irrigation devices reconstitute solutions using boiled, distilled, or sterile water.

I hope this brief summary has expanded your view of waterborne disease in the United States. The new face of waterborne disease means we now need to think about oral, dermal, and respiratory transmission routes, an expanded set of pathogens, and the many uses of water beyond drinking, such as recreational, medical, and industrial uses, particularly in the context of the built environment. Integrating this understanding into everyday clinical histories, lab requests, and anticipatory guidance for patients should help you better diagnose waterborne disease and educate your patients about simple disease prevention measures. Thank you.

Web Resources

CME Accredited Course on Waterborne Disease

Recognizing Waterborne Disease and the Health Effects of Water Pollution

This online course on waterborne disease offers Continuing Medical Education Credits (CME) and Maintenance of Certification Credits (MOC) (maximum 22 credit hours). It is sponsored by the American College of Preventive Medicine.

Drinking Water

CDC: Drinking Water

CDC: Private Ground Water Wells

American Academy of Pediatrics: Drinking Water From Private Wells and Risks to Children

Recreational Water

CDC: Healthy Swimming/Recreational Water

CDC: Parasites -- Cryptosporidium

Built Environment

CDC: Legionellosis Resource Site

CDC: Acanthamoeba

Climate Change

CDC: Naegleria fowleri -- Primary Amebic Meningoencephalitis (PAM)

Michael Beach, PhD , is Associate Director for Healthy Water in CDC's National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). He is also Chief of the Waterborne Disease Prevention Branch, which oversees the Center's waterborne disease activities, including domestic and international waterborne disease outbreak investigations, national surveillance for cryptosporidiosis and giardiasis, and the national Waterborne Disease and Outbreak Surveillance System.

He is a strong advocate for reducing the global burden of water-, sanitation-, and hygiene-related disease. His domestic interests include collecting and solidifying data that will better characterize the magnitude and burden of waterborne disease in the United States to increase recognition of domestic waterborne disease transmission and improve future prevention efforts.

Dr. Beach received his PhD in Biochemistry from Purdue University in 1987. He joined the Centers for Disease Control and Prevention (CDC) in 1989 and served in CDC's Epidemic Intelligence Service from 1995 to 1997.