Waterborne illnesses sicken more than 7 million Americans and kill over 6,600 every year, warns CDC
The estimates are based on not just water that people in the US drink, but also the water in swimming pools, waterparks, water playgrounds and hot tubs
The provision of safe drinking water is considered a public health achievement in the US, but researchers caution that new waterborne disease challenges have emerged. They are responsible for 7.15 million waterborne illnesses every year and close to 7,000 deaths, according to an analysis by the US Centers for Disease Control and Prevention (CDC).
Otitis externa, commonly referred to as “swimmer’s ear,” and norovirus infection were the most common illnesses. Most hospitalizations and deaths were caused by biofilm-associated pathogens: nontuberculous mycobacteria (NTM), Pseudomonas and Legionella. Biofilm forms when bacteria, fungi, algae, yeasts, protozoa, and other microorganisms adhere to surfaces in moist environments by excreting a glue-like substance. Experts say that waterborne germs can live and grow in the pipes and in devices one uses that require water, and some of them can be harmful and make people ill.
“The complexity and scope of water use has increased; drinking, sanitation, hygiene, cooling, and heating needs are supported by 6 million miles of plumbing inside US buildings (that is, premise plumbing). Premise plumbing water quality can be compromised by long water residency times, reduced disinfectant levels, and inadequate hot water temperatures, creating environments where pathogens can amplify in biofilms,” explains the agency. It adds, “People can be exposed to these pathogens through contact, ingestion, or inhalation of aerosols (for example, from showerheads, building cooling towers, or decorative fountains).”
Stating that the findings reflect the changing picture of waterborne disease in the US and underscore the role of environmental pathogens that grow in biofilms, experts have called for the need to focus public health resources on the prevention and control of the diseases, including surveillance for the diseases in this estimate that does not have a dedicated national case surveillance system. “These findings should serve as a foundation for improved disease surveillance, inform waterborne disease prevention priorities, and help measure progress in the prevention of waterborne disease in the US,” they emphasize.
118,000 hospitalizations and over $3B in healthcare costs
The analysis focuses on total illnesses, emergency department visits, hospitalizations, deaths, and direct healthcare costs for 17 infectious diseases that can spread through contaminated water, and includes all water sources (drinking, recreational, and environmental) and exposure routes (ingestion, contact, and inhalation). This implies that the estimates are based on not just water that Americans drink, but also the water in swimming pools, waterparks, water playgrounds and hot tubs.
“We estimate that 33,600,000 illnesses from the diseases in this analysis occurred in 2014, and of those, 7,150,000 were attributed to waterborne transmission in the US. The diseases that caused the greatest number of domestically acquired waterborne illnesses were otitis externa, (4,670,000 illnesses), and norovirus infection (1,330,000), followed by giardiasis (415,000) and cryptosporidiosis (322,000). An estimated 96,000 domestically acquired waterborne respiratory illnesses occurred, and 2,330,000 domestically acquired waterborne enteric illnesses occurred,” the authors write in the Emerging Infectious Diseases journal.
An estimated 601,000 treat-and-release emergency department visits were caused by waterborne transmission. Otitis externa caused the bulk of the visits at 567,000. The experts further show that the diseases were responsible for 118,000 hospitalizations attributed to waterborne transmission. The diseases with the largest number of hospitalizations were NTM infection (51,400 hospitalizations), otitis externa (23,200), and Pseudomonas pneumonia (15,500). About 77,700 respiratory and 10,900 enteric (relating to or occurring in the intestines) hospitalizations were attributed to waterborne transmission.
About 6,630 deaths were due to waterborne transmission. NTM infection (3,800), Legionnaires’ disease (995), and Pseudomonas pneumonia (730) were responsible for the largest number of deaths. The results reveal that 5,530 deaths from respiratory disease 131 deaths from enteric diseases were attributed to waterborne transmission.
The germs also rack up billions in health care costs. Domestic waterborne transmission incurred $3.33 billion in hospitalization and emergency department visit costs. Pseudomonas septicemia had the highest cost per hospital stay ($38,200), followed by Legionnaires’ disease ($37,300). The costliest diseases were NTM infection ($1.53 billion), otitis externa ($564 million), and Pseudomonas pneumonia ($453 million). An estimated $2.39 billion and $160 million in direct healthcare costs from domestically acquired waterborne respiratory disease and enteric diseases respectively, were incurred.
“Although the risk of illness from enteric pathogens readily controlled by water treatment processes still exists, this analysis highlights the expanding role of environmental pathogens (for example, mycobacteria, Pseudomonas, Legionella) that can grow in drinking water distribution systems; plumbing in hospitals, homes, and other buildings; recreational water venues; and industrial water systems (such as cooling towers). This snapshot of waterborne disease transmission contrasts with historical waterborne disease transmission before the implementation of drinking water treatment and sanitation systems (such as cholera, typhoid fever, and other enteric pathogens),” concludes the team.