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.

Results

Illnesses

We estimate that 33,600,000 (95% CrI 23,500,000–48,000,000) illnesses from the diseases in this analysis occurred in 2014, and of those, 7,150,000 (95% CrI 3,880,000–12,000,000; 21.3%) were attributed to waterborne transmission in the United States (Table 2). The diseases that caused the greatest number of domestically acquired waterborne illnesses were otitis externa (4,670,000 illnesses; 95% CrI 2,350,000–7,290,000) and norovirus infection (1,330,000 illnesses; 95% Cr 5,310–5,510,000), followed by giardiasis (415,000 illnesses; 95% CrI 140,000–816,000) and cryptosporidiosis (322,000 illnesses; 95% CrI 61,700–993,000). An estimated 96,000 domestically acquired waterborne respiratory illnesses occurred, and 2,330,000 domestically acquired waterborne enteric illnesses occurred.

Emergency Department Visits

An estimated 601,000 (95% CrI 364,000–866,000) treat-and-release emergency department visits for the included diseases were attributed to waterborne transmission in the United States in 2014 (Table 3). Otitis externa caused the largest number of visits (567,000; 95% CrI 337,000–823,000).

Hospitalizations

We estimate that these diseases were responsible for 118,000 (95% CrI 86,800–150,000) hospitalizations attributed to waterborne transmission in the United States (Table 3). The diseases with the largest number of hospitalizations were NTM infection (51,400 hospitalizations; 95% CrI 26,800–74,100), otitis externa (23,200 hospitalizations; 95% CrI 13,900–33,600), and Pseudomonas pneumonia (15,500 hospitalizations; 95% CrI 4,130–28,100). An estimated 77,700 respiratory hospitalizations were attributed to waterborne transmission, and 10,900 enteric hospitalizations were attributed to waterborne transmission.

Deaths

The diseases examined in this analysis were responsible for 6,630 deaths (95% CrI 4,520–8,870) attributed to waterborne transmission in the United States in 2014 (Table 3). The diseases with the largest number of deaths attributed to waterborne transmission in the United States were NTM infection (3,800, 95% CrI 1,950–5,620), Legionnaires' disease (995, 95% CrI 655–1,310), and Pseudomonas pneumonia (730, 95% CrI 185–1,460). An estimated 5,530 deaths from respiratory disease were attributed to waterborne transmission (83% of all domestically acquired waterborne deaths), and 131 deaths from enteric diseases were attributed to waterborne transmission.

Direct Healthcare Costs of ED Visits and Hospitalizations

Pseudomonas septicemia had the highest cost per hospital stay ($38,200; 95% CrI $6,340–$172,000), followed by Legionnaires' disease ($37,300, CrI $7,950–$149,000) (Table 4). Payments for ED visits and hospitalizations attributed to waterborne transmission in the United States totaled US $3.33 billion (95% CrI $1.37–$8.77 billion) in 2014 dollars (Table 5). This amount included $1.33 billion (95% CrI $361 million–$4.44 billion) in commercial insurer payments, $1.52 billion (95% CrI $338 million–$5.84 billion) in Medicare payments, and $284 million (95% CrI $62.7 million–$906 million) in Medicaid payments (Appendix 3 Tables 1–3). The costliest diseases were NTM infection ($1.53 billion; 95% CrI $272 million–$6.38 billion), otitis externa ($564 million; 95% CrI $187 million–$1.57 billion), and Pseudomonas pneumonia ($453 million; 95% CrI $49.9 million–$1.95 billion). An estimated $2.39 billion in direct healthcare costs from domestically acquired waterborne respiratory disease were incurred (72% of all costs from domestically acquired waterborne disease), as were $160 million in direct healthcare costs from domestically acquired waterborne enteric diseases.

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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

Results

Illnesses

Emergency Department Visits

Hospitalizations

Deaths

Direct Healthcare Costs of ED Visits and Hospitalizations

Tables

Tables

Tables

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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