Estimate of Burden and Direct Healthcare Cost of Infectious Waterborne Disease in the United States

Sarah A. Collier; Li Deng; Elizabeth A. Adam; Katharine M. Benedict; Elizabeth M. Beshearse; Anna J. Blackstock; Beau B. Bruce; Gordana Derado; Chris Edens; Kathleen E. Fullerton; Julia W. Gargano; Aimee L. Geissler; Aron J. Hall; Arie H. Havelaar; Vincent R. Hill; Robert M. Hoekstra; Sujan C. Reddy; Elaine Scallan; Erin K. Stokes; Jonathan S. Yoder; Michael J. Beach

Disclosures

Emerging Infectious Diseases. 2021;27(1):140-149.

Abstract and Introduction

Abstract

Provision of safe drinking water in the United States is a great public health achievement. However, new waterborne disease challenges have emerged (e.g., aging infrastructure, chlorine-tolerant and biofilm-related pathogens, increased recreational water use). Comprehensive estimates of the health burden for all water exposure routes (ingestion, contact, inhalation) and sources (drinking, recreational, environmental) are needed. We estimated total illnesses, emergency department (ED) visits, hospitalizations, deaths, and direct healthcare costs for 17 waterborne infectious diseases. About 7.15 million waterborne illnesses occur annually (95% credible interval [CrI] 3.88 million–12.0 million), results in 601,000 ED visits (95% CrI 364,000–866,000), 118,000 hospitalizations (95% CrI 86,800–150,000), and 6,630 deaths (95% CrI 4,520–8,870) and incurring US $3.33 billion (95% CrI 1.37 billion–8.77 billion) in direct healthcare costs. Otitis externa and norovirus infection were the most common illnesses. Most hospitalizations and deaths were caused by biofilm-associated pathogens (nontuberculous mycobacteria, Pseudomonas, Legionella), costing US $2.39 billion annually.

Introduction

At the beginning of the 20th century, diseases commonly transmitted by water, such as cholera and typhoid, were major causes of death in the United States.^[1] Reliable provision of treated, safe drinking water dramatically reduced the burden of these diseases and has been recognized as one of the greatest public health achievements of the 20th century.^[2] Despite this achievement, waterborne disease in the United States persists.^[3–5]

In the United States, outbreaks associated with large public drinking water systems have sharply declined in the past 40 years,^[3,6] likely the result of improvements in regulation and operation. However, transmission of disease via drinking water systems still occurs, often attributable to aging infrastructure, operational challenges, and the private or unregulated water systems (e.g., private wells) that serve an estimated 43 million persons.^[7] At the same time, 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 (i.e., premise plumbing).^[8,9] Premise plumbing water quality can be compromised by long water residency times, reduced disinfectant levels, and inadequate hot water temperatures, creating environments where pathogens (e.g., nontuberculous mycobacteria [NTM], Pseudomonas, and Legionella) can amplify in biofilms.^[10] People can be exposed to these pathogens through contact, ingestion, or inhalation of aerosols (e.g., from showerheads, building cooling towers, or decorative fountains).

As leisure time has increased, swimming pools, waterparks, water playgrounds, and hot tubs have proliferated.^[5] These venues rely largely on chlorination as the major barrier against disease transmission. Cryptosporidium has emerged as the major cause of outbreaks associated with treated aquatic venues because it is extremely chlorine resistant and has a low infectious dose.^[5,11,12] Warmer oceans have led to Vibrio-associated wound infections farther north than previously documented.^[13]

Estimates of the overall burden of foodborne disease in the United States, including both known and unknown agents, have been useful in directing prevention activities and setting public health goals.^[14,15] Quantifying the burden of infectious waterborne disease in the United States would also be beneficial.

Previous studies have attempted to estimate the burden of gastrointestinal illness^[16,17] or all illness associated with drinking water^[18] and untreated recreational water^[19] in the United States, but the burden of disease from all water sources (drinking, recreational, environmental) and exposure routes (ingestion, contact, inhalation) has not been estimated. We present an estimate of the burden of waterborne disease in the United States that includes gastrointestinal, respiratory, and systemic disease; accounts for underdiagnosis; and includes all water sources and exposure routes.

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Abstract and Introduction
Methods
Results
Discussion
References

Table 1. Data sources used to estimate the total number of illnesses for selected infectious diseases, United States*
Active surveillance data (name of surveillance system)	Passive surveillance data	Administrative data
Campylobacteriosis (FoodNet)	Giardiasis (NNDSS)	NTM infection (HCUP NEDS/NIS)
Cryptosporidiosis (FoodNet)	Legionnaires' disease (NNDSS)	Otitis externa (NAMCS, HCUP NEDS/NIS)
Norovirus (20,21)	Vibrio spp. infection (COVIS)	Pseudomonas pneumonia (HCUP NEDS/NIS)
Salmonellosis, nontyphoidal (FoodNet)	Vibrio alginolyticus infection (COVIS)	Pseudomonas septicemia (HCUP NEDS/NIS)
STEC infection, O157 (FoodNet)	Vibrio parahaemolyticus infection (COVIS)
STEC infection, non-O157 (FoodNet)	Vibrio vulnificus infection (COVIS)
Shigellosis (FoodNet)	Other Vibrio infection (COVIS)

*COVIS, Cholera and Other Vibrio Illness Surveillance; FoodNet, Foodborne Diseases Active Surveillance Network; HCUP NEDS/NIS, Healthcare Cost and Utilization Project's National Emergency Department Sample and National Inpatient Sample; NAMCS, National Ambulatory Medical Care Survey; NNDSS, National Notifiable Diseases Surveillance System; NTM, nontuberculous mycobacterial; STEC, Shiga toxin–producing Escherichia coli.

Table 2. Estimated number of total cases of domestically acquired waterborne illness in 2014 for selected infectious diseases, United States*
Disease or syndrome	Estimated confirmed cases	Multipliers		Estimated total cases (95% CrI)	International travel, %	Waterborne, % (95% CrI)	Domestically acquired waterborne, no. (95% CrI)
Disease or syndrome	Estimated confirmed cases	Under-reporting	Under-diagnosis	Estimated total cases (95% CrI)	International travel, %	Waterborne, % (95% CrI)	Domestically acquired waterborne, no. (95% CrI)
Campylobacteriosis	54,000	1.0	28.3	1,540,000 (597,000–3,250,000)	14.4	13 (1–31)	171,000 (13,900–586,000)
Cryptosporidiosis	8,450	1.0	97.3	823,000 (243,000–2,160,000)	9.9	43 (17–73)	322,000 (61,700–993,000)
Giardiasis	17,900	1.30	45.9	1,070,000 (727,000–1,560,000)	12.3	44 (16–78)	415,000 (140,000–816,000)
Legionnaires' disease	5,030	1.0	2.3	11,400 (8,920–13,600)	1.0	97 (67–100)	11,000 (7,430–13,300)
NTM infection	25,700	1.0	3.8	97,000 (75,700–122,000)	1.0	72 (39–94)	68,900 (35,800–100,000)
Norovirus	NA	1.0	NA	21,800,000 (12,100,000–36,000,000)	1.1	6 (0–25)	1,330,000 (5,310–5,510,000)
Otitis externa†	1,720,000	1.0	3.4	5,980,000 (3,200,000–8,880,000)	1.3	79 (67–95)†	4,670,000 (2,350,000–7,290,000)
Pseudomonas pneumonia	15,800	1.0	2.0	31,700 (19,300–46,000)	1.0	51 (14–80)	15,900 (4,240–29,000)
Pseudomonas septicemia	13,000	1.0	2.0	26,100 (16,700–35,900)	1.0	22 (3–53)	5,760 (743–14,400)
Salmonellosis, nontyphoidal	46,400	1.0	29.1	1,350,000 (733,000–2,450,000)	9.7	6 (0–22)	77,000 (5,640–277,000)
STEC infection, serotype O157	3,530	1.0	18.2	64,200 (13,000–188,000)	4.0	5 (1–13)	3,360 (336–12,900)
STEC infection, serotype non-O157	4,550	1.0	48.1	219,000 (80,000–493,000)	15.3	6 (0–17)	11,400 (0–43,900)
Shigellosis	13,600	1.0	33.1	449,000 (97,800–1,350,000)	7.8	4 (1–21)	17,300 (1,080–77,500)
Vibrio spp. infection	1,230	NA	NA	172,000 (126,000–231,000)	NA	NA	34,600 (17,600–56,900)
V. alginolyticus	234	1.1	142.8	36,700 (23,600–54,800)	6.5	37 (13–71)	12,700 (4,100–25,400)
V. parahaemolyticus	593	1.1	141.6	92,400 (55,000–144,000)	6.7	24 (7–38)	20,800 (6,000–39,000)
V. vulnificus	133	1.1	1.7	249 (178–340)	1.5	77 (40–91)	188 (93–277)
Other Vibrio	271	1.1	142.8	42,600 (25,500–66,500)	14.4	2 (0–23)	879 (3–8,490)
Total illness	NA	NA	NA	33,600,000 (23,500,000–48,000,000)	NA	NA	7,150,000 (3,880,000–12,000,000)

*Estimates rounded to 3 significant figures. CrI, credible interval; NA, not applicable; NTM, nontuberculous mycobacteria; STEC, Shiga toxin–producing Escherichia coli.
†Combines the waterborne source attribution (25) for Pseudomonas spp. otitis externa (81%) and Staphylococcus aureus (75%) in a ratio of 2:1. More details provided in Appendix 1 (https://wwwnc.cdc.gov/EID/article/27/1/19-0676-App1.pdf).

Table 3. Estimated number of treat-and-release emergency department visits, hospitalizations, and deaths from domestically acquired waterborne transmission in 2014 for selected infectious diseases, United States*
Disease or syndrome	Treat-and-release ED visits†		Hospitalizations			Deaths
Disease or syndrome	Total visits (95% CrI)	Domestic waterborne visits (95% CrI)	% Admitted to hospital	Total stays (95% CrI)	Domestic waterborne stays (95% CrI)	% Deaths	Total deaths (95% CrI)	Domestic waterborne deaths (95% CrI)
Campylobacteriosis	2,900 (1,620–4,630)	319 (31–966)	19.5	19,300 (8,790–34,900)	2,150 (192–6,900)	0.2	242 (0–1,150)	27 (0–146)
Cryptosporidiosis	1,260 (742–1,880)	492 (167–957)	19.2	2,870 (439–8,060)	1,120 (102–3,550)	0.3	61 (0–320)	24 (0–136)
Giardiasis	1,460 (902–2,090)	567 (185–1,120)	7.9	2,830 (1,760–4,070)	1,100 (364–2,180)	<0.1	4 (0–11)	1 (0–5)
Legionnaires' disease	691 (316–1,220)	667 (289–1,200)	98.1	11,200 (8,750–13,300)	10,800 (7,280–13,100)	9.0	1,030 (762–1,330)	995 (655–1,310)
NTM infection	7,150 (5,110–9,620)	5,080 (2,560–7,750)	74.8	72,400 (57,300–89,700)	51,400 (26,800–74,100)	5.5	5,350 (4,020–6,920)	3,800 (1,950–5,620)
Norovirus	429,000‡ (318,000–605,000)	26,300‡ (105–106,000)	0.4	78,100 (58,500–104,000)	4,780 (19–19,300)	<0.1	885 (742–1,120)	54 (0–219)
Otitis externa	726,000 (466,000–994,000)	567,000 (337,000–823,000)	0.9	29,700 (19,200–40,600)	23,200 (13,900–33,600)	<0.1	280 (144–452)	219 (107–367)
Pseudomonas pneumonia	580 (321–902)	291 (75–552)	97.2	30,800 (18,700–44,700)	15,500 (4,130–28,100)	4.6	1,450 (786–2,420)	730 (185–1,460)
Pseudomonas septicemia	164 (36–326)	36 (2–106)	97.2	25,300 (16,300–34,800)	5,590 (722–14,000)	12.1	3,140 (1,990–4,430)	695 (89–1,740)
Salmonellosis, nontyphoidal	3,410 (2,100–4,900)	194 (15–671)	28.4	26,600 (11,400–52,800)	1,520 (100–5,660)	0.5	421 (0–1,140)	24 (0–103)
STEC infection, serotype O157	252 (92–465)	12 (2–35)	38.5	2,640 (487–7,630)	138 (14–503)	0.7	36 (0–314)	2 (0–17)
STEC infection, serotype non-O157	75 (12–171)	4 (0–16)	16.0	1,420 (264–3,810)	74 (0–308)	0.2	16 (0–184)	1 (0–12)
Shigellosis	1,650 (540–2,870)	64 (5–311)	24.4	6,380 (929–20,300)	245 (12–1,140)	0.1	26 (0–218)	1 (0–9)
Vibrio spp. infection	366 (122–700)	76 (14–166)	NA	782 (567–1,030)	251 (153–362)	NA	113 (67–156)	60 (27–92)
V. alginolyticus	NA§	NA§	15.9	74 (38–141)	26 (8–58)	0.8	4 (0–11)	1 (0–5)
V. parahaemolyticus	NA§	NA§	22.3	264 (136–410)	60 (16–112)	1.4	16 (7–32)	4 (1–9)
V. vulnificus	NA§	NA^‡	85.4	213 (147–297)	161 (79–241)	28.8	72 (38–104)	54 (24–85)
Other Vibrio	NA§	NA§	42.5	231 (134–350)	5 (0–46)	3.8	20 (11–33)	0 (0–4)
Total	1,180,000 (877,000–1,490,000)	601,000 (364,000–866,000)	NA	310,000 (263,000–360,000)	118,000 (86,800–150,000)	NA	13,100 (10,600–15,900)	6,630 (4,520–8,870)

*Estimates rounded to 3 significant figures. CrI, credible interval; ED, emergency department; NA, not applicable; NTM, nontuberculous mycobacterial; STEC, Shiga toxin–producing Escherichia coli.
†Treat-and-release ED visits were defined as visits in which the person was not admitted to the hospital.
‡For norovirus infection only, ED visits in which the person was admitted to the hospital were included, for consistency with previous published estimates.
§No International Classification of Diseases, 9th Revision, Clinical Modification, codes are available for Vibrio spp. infections, only a general code for "Vibriosis and cholera." ED visit estimates relied on administrative data that used these codes, and thus are presented only for Vibrio infection overall.

Table 4. Cost per hospital stay for selected diseases that can be transmitted by water, 2012–2013 IBM MarketScan health insurance databases, United States*
Disease/syndrome	Cost in 2014 US dollars (95% CrI)
Disease/syndrome	Commercial insurance	Medicare	Medicaid	Overall
Campylobacteriosis	15,200 (1,520–47,100)	15,100 (1,630–55,300)	5,900 (85–29,000)	13,600 (3,850–35,800)
Cryptosporidiosis	17,900 (1,560–82,700)	17,300 (1,800–79,400)	10,700 (22–64,200)	16,100 (4,360–55,400)
Giardiasis	25,300 (1,790–168,000)	22,300 (1,890–96,900)	14,300 (159–88,000)	21,800 (6,160–99,200)
Legionnaires' disease	45,900 (2,320–306,000)	33,600 (4,210–183,000)	18,700 (17–99,300)	37,100 (7,950–149,000)
NTM infection	44,100 (1,650–244,000)	27,600 (1,720–152,000)	14,800 (49–69,100)	29,600 (6,350–120,000)
Norovirus infection†				6,080
Otitis externa	13,800 (1,480–56,500)	14,400 (1,490–65,100)	6,680 (43–36,900)	12,200 (3,320–42,400)
Pseudomonas pneumonia	45,100 (1,510–193,000)	28,200 (1,890–146,000)	11,600 (18–53,200)	29,300 (5,910–114,000)
Pseudomonas septicemia	63,600 (1,450–386,000)	34,400 (2,200–181,000)	19,800 (47–113,000)	38,200 (6,340–172,000)
Salmonellosis, nontyphoidal	17,200 (2,010–73,600)	17,100 (1,400–62,700)	6,940 (70–26,300)	14,900 (4,300–46,900)
STEC infection, serotype O157	25,900 (2,410–150,000)	17,200 (1,860–82,200)	4,530 (3–30,200)	19,000 (3,790–85,000)
STEC infection, serotype non-O157	23,600 (1,390–95,700)	31,900 (2,620–250,000)	5,020 (458–32,000)	24,200 (4,780–138,000)
Shigellosis	19,000 (2,910–85,300)	13,500 (1,610–39,600)	7,710 (37–51,300)	14,200 (4,130–48,000)
Vibrio spp. infection	17,400 (2,260–50,500)	18,400 (0,977–78,700)	4,600 (13–46,000)	16,000 (3,780–39,900)

*Estimates rounded to 3 significant figures. Overall cost calculated using the sum of insurer and out-of-pocket payments per stay for each payment source multiplied by the proportion of persons in the Health Care Utilization Project's Nationwide Inpatient Sample with each payment source, for the corresponding disease or syndrome. This produces a weighted average cost per stay that reflects the differing proportion of payment sources for each disease or syndrome. Persons who had a payment source other than commercial insurance, Medicare, or Medicaid (i.e., persons covered by Tricare (the healthcare plan for persons affiliated with the US armed services, who were uninsured, or who had an unknown source of insurance) were assumed to have a cost per stay equivalent to the commercial insurance cost per stay. NTM, nontuberculous mycobacterial; STEC, Shiga toxin–producing Escherichia coli.
†Norovirus costs were derived from previously published estimates that did not specify cost per insurance source or include uncertainty intervals.

Table 5. Total direct healthcare cost of ED visits and hospitalizations from domestically acquired waterborne transmission of selected infectious diseases, United States, 2014*
Disease or syndrome	Value (95% CrI)
	Treat-and-release ED visits†			Hospitalization			Direct healthcare cost, millions
	Cost per visit	Total no. visits	Total cost, millions	Cost per stay	Total no. hospital stays	Total cost, millions	Direct healthcare cost, millions
Campylobacteriosis	1,710 (137–5,810)	319 (31–966)	0.545 (0.0177–2.61)	13,600 (3,850–35,800)	2,150 (192–6,900)	30.0 (1.71–121)	30.5 (2.10–121)
Cryptosporidiosis	1,960 (238–6,270)	492 (167–957)	0.963 (0.0802–3.44)	16,100 (4,360–55,400)	1,120 (102–3,550)	17.9 (1.10–79.5)	18.9 (1.82–80.4)
Giardiasis	1,620 (196–7,510)	567 (185–1,120)	0.917 (0.0861–3.78)	21,800 (6,160–99,200)	1,100 (364–2,180)	23.9 (3.53–104)	24.8 (4.21–105)
Legionnaires' disease	691 (288–1,390)	667 (289–1,200)	0.460 (0.127–1.13)	37,100 (7,950–149,000)	10,800 (7,280–13,100)	401 (79.0–1,690)	402 (79.5–1,690)
NTM infection	1,610 (129–6,430)	5,080 (2,560–7,750)	8.17 (0.584–34.0)	29,600 (6,350–120,000)	51,400 (26,800–74,100)	1,520 (266–6,370)	1,530 (272–6,380)
Norovirus‡	1,140	26,300	30.1	6,080	4,780	29	59.1
Otitis externa	494 (120–1,430)	567,000 (337,000–823,000)	280 (60.2–846)	12,200 (3,320–42,400)	23,200 (13,900–33,600)	285 (67.8–1,040)	564 (187–1,570)
Pseudomonas pneumonia	856 (89–4,190)	291 (75–552)	0.249 (0.0162–1.27)	29,300 (5,910–114,000)	15,500 (4,130–28,100)	452 (49.8–1,950)	453 (49.9– 1,950)
Pseudomonas septicemia	923 (95–3,190)	36 (2–106)	0.0334 (0.000716–0.186)	38,200 (6,340–172,000)	5,590 (722–14,000)	214 (11.4–1,030)	214 (11.4–1,030)
Salmonellosis, nontyphoidal	1,230 (161–4,500)	194 (15–671)	0.240 (0.00734–1.24)	14,900 (4,300–46,900)	1,520 (100–5,660)	22.6 (0.870–110)	22.8 (1.08–110)
STEC infection, serotype O157	1,070 (109–2,350)	12 (2–35)	0.0130 (0.00734–0.051)	19,000 (3,790–85,000)	138 (14–503)	2.67 (0.129–14.5)	2.68 (0.141–14.5)
STEC infection, serotype non-O157	1,070 (109–2,350)	4 (0–16)	0.00440 (0–0.0223)	24,200 (4,780–138,000)	74 (0–308)	1.76 (0–11.0)	1.76 (0.00186–11.0)
Shigellosis	952 (115–3,980)	64 (5–311)	0.0609 (0.00171–0.349)	14,200 (4,130–48,000)	245 (13–1,140)	3.41 (0.106–18.9)	3.47 (0.140–19.0)
Vibrio spp. infection	1,030 (293–3,330)	76 (14–166)	0.0777 (0.00765–0.276)	16,000 (3,780–39,900)	251 (153–362)	4.02 (0.811–10.7)	4.10 (0.891–10.8)
Total cost			322 (100–889)			3,010 (1,120–8,410)	3,330 (1,370–8,770)

*Values are 2004 US dollars except as indicated. Estimates rounded to 3 significant figures. CrI, credible interval; ED, emergency department; NTM, nontuberculous mycobacterial; STEC, Shiga toxin-producing E. coli.
†Treat-and-release ED visits were defined as visits in which the person was not admitted to the hospital.
‡For norovirus only, costs were derived from previously published estimates that did not include uncertainty intervals. In addition, the number of ED visits includes visits in which the patient was admitted to the hospital.

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Estimate of Burden and Direct Healthcare Cost of Infectious Waterborne Disease in the United States

Abstract and Introduction

Abstract

Introduction

Tables

Tables

Tables

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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