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

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.

Estimated burden of keratitis--United States, 2010.

Keratitis, inflammation of the cornea, can result in partial or total loss of vision and can result from infectious agents (e.g., microbes including bacteria, fungi, amebae, and viruses) or from noninfectious causes (e.g., eye trauma, chemical exposure, and ultraviolet exposure). Contact lens wear is the major risk factor for microbial keratitis; outbreaks of Fusarium and Acanthamoeba keratitis have been associated with contact lens multipurpose solution use, and poor contact lens hygiene is a major risk factor for a spectrum of eye complications, including microbial keratitis and other contact lens-related inflammation. However, the overall burden and the epidemiology of keratitis in the United States have not been well described. To estimate the incidence and cost of keratitis, national ambulatory-care and emergency department databases were analyzed. The results of this analysis showed that an estimated 930,000 doctor's office and outpatient clinic visits and 58,000 emergency department visits for keratitis or contact lens disorders occur annually; 76.5% of keratitis visits result in antimicrobial prescriptions. Episodes of keratitis and contact lens disorders cost an estimated $175 million in direct health care expenditures, including $58 million for Medicare patients and $12 million for Medicaid patients each year. Office and outpatient clinic visits occupied over 250,000 hours of clinician time annually. Developing effective prevention messages that are disseminated to contact lens users and investigation of additional preventive efforts are important measures to reduce the national incidence of microbial keratitis.

The incidence and health burden of earaches attributable to recreational swimming in natural waters: a prospective cohort study.

BACKGROUND: Earaches and outer ear infections are commonly associated with swimming. In this study, we estimated the excess risk and health burden of earaches due to swimming in natural fresh and marine waters using results from a survey of over 50,000 beachgoers at nine beaches across the United States. METHODS: Prospective cohort studies were conducted at four freshwater and five marine sites in the United States and Puerto Rico. Beach visitors were enrolled on summer weekends and holidays. Ten to twelve days after the beach visit, respondents answered questions about health symptoms, including earaches or ear infections experienced since the beach visit. Economic and physical burdens were also obtained. Fixed slope, random intercept (beach site) multivariate logistic regression models were used to estimate the relationship between head immersion swimming exposure and earaches. Model results were used to calculate excess risk for earaches attributable to swimming. RESULTS: The overall incidence of self-reported earache was 1.6% in the 10-12 days after the beach visit. Earaches were more frequent in head immersion swimmers compared to non-swimmers for all beach sites and age groups. Earaches were unassociated with water sample measures of fecal contamination and turbidity. After adjustment for covariates, we calculated 7.12 excess earaches among head immersion swimmers per 1,000 swimming events. Twenty-four percent of those with earache reported missing their regular activities; 28% visited a doctor; 4% visited the emergency room; and 31% and 40% used prescription and non-prescription medications, respectively. CONCLUSIONS: There are at least 128 million swimming events in natural waters annually. Such frequent exposures could result in 900,000 excess earaches, 260,000 visits to the doctor, 39,900 visits to the emergency room, nearly $4 million dollars in out-of-pocket expenditures on prescription and over-the-counter medications, and close to 75,000 hours of clinician time. More accurate estimates of swimming exposure are needed to improve population burden and associated cost estimates.

Economic and health impacts associated with a Salmonella Typhimurium drinking water outbreak-Alamosa, CO, 2008.

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak's estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677-$6,002,879), and rose to $2.6 million dollars (range: $1,123,471-$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks.

The Leogane, Haiti demonstration project: decreased microfilaremia and program costs after three years of mass drug administration.

To support the global program to eliminate lymphatic filariasis (LF), well-monitored demonstration projects are important for defining the relationship between coverage and reductions in microfilaremia. We are using mass treatment with diethylcarbamazine (DEC) and albendazole in an effort to eliminate LF from Leogane, Haiti. Wuchereria bancrofti microfilaremia prevalence at baseline ranged from 0.8% to 15.9% in four sentinel sites. After three rounds of DEC-albendazole mass drug administration (MDA), both microfilaremia prevalence and intensity decreased dramatically. Mild and moderate adverse reactions after treatment were common, especially after the first MDA, but decreased after subsequent MDAs. Drug coverage for the first year was estimated to be 72%, but concerns about adverse reactions appeared to decrease drug coverage in the second MDA. As a result of community education efforts that focused on providing a greater understanding of adverse reactions, coverage increased dramatically for the third round. Program efficiency increased substantially; the costs per person treated for three rounds of MDA were 2.23 US dollars, 1.96 US dollars, and 1.30 US dollars per person, respectively. The Leogane experience highlights the importance of adapting community education and mobilization campaigns to achieve and maintain good coverage.

Ultrasonographic examination of Haitian children with lymphatic filariasis: a longitudinal assessment in the context of antifilarial drug treatment.

To assess the clinical findings associated with detection of adult Wuchereria bancrofti worms on ultrasound, 186 schoolchildren in a filariasis-endemic area of Haiti underwent physical and ultrasonographic examinations. The filaria dance sign (FDS) of adult W. bancrofti was detected in the inguinal and crural lymphatics of 28 (15%) children. FDS detection was more common in older children (P = 0.003) and in those with a history of inguinal lymph node inflammation (P = 0.002) or crural lymphadenopathy on physical exam (P = 0.01). Twenty-five FDS-positive children were reexamined after three annual cycles of mass treatment for lymphatic filariasis (LF). The total number of adult worm nests detected by ultrasound decreased from 29 to 4 (P

Frequency, severity, and costs of adverse reactions following mass treatment for lymphatic filariasis using diethylcarbamazine and albendazole in Leogane, Haiti, 2000.

In October 2000, 71,187 persons were treated for lymphatic filariasis using albendazole and diethylcarbamazine (DEC) or DEC alone in Leogane, Haiti. We documented the frequency of adverse reactions, severity and cost of treatment. Adverse reactions were classified as minor, moderate, or severe. Overall, 24% (17,421) of the treated persons reported one or more adverse reactions. There were 15,916 (91%) minor and 1502 (9%) moderate adverse reaction reports. Men outnumbered women 2:1 in reporting moderate problems. Three patients, representing roughly one in 25,000 persons treated, were hospitalized with severe adverse reactions judged to be treatment-associated by physician review. The cost per person treated for adverse reactions was more than twice the cost per person treated for lymphatic filariasis (dollar 1.60 versus dollar 0.71). Severe adverse reactions to lymphatic filariasis treatment using DEC with or without albendazole are uncommon. Minor and moderate reactions are more commonly reported and their management represents a challenge to lymphatic filariasis elimination programs.

Comparison of methods for estimating drug coverage for filariasis elimination, Leogane Commune, Haiti.

In the global effort to eliminate lymphatic filariasis, annual mass treatments are conducted with diethylcarbamazine (DEC) or ivermectin, combined with albendazole. The success of this strategy depends on achieving high levels of drug coverage, which reduces the number of persons with circulating microfilariae so that transmission of the parasite is interrupted. Because resources are often limited, a simple, inexpensive, and reliable method to estimate drug coverage is needed. During the period December 2000 to February 2001, three methods were used to assess drug coverage in Leogane Commune, Haiti: a probability survey using a cluster sample design (n = 1421 persons); a distribution-point survey based on a convenience sample of houses near the distribution points (n = 4341 persons); and a survey based on a convenience sample of primary schools (n = 5036 children). The coverage estimations were 71.3% (95% CI 66.7-75.9), 73.6% (95% CI 70.1-77.0), and 77.8% (95% CI 73.5-82.1), respectively. Survey costs for the probability, distribution point, and school surveys were US$2217, US$979, and US$312, respectively. The 2 convenience sampling methods provided point estimates of drug coverage that were similar to those of the probability survey. These methods may have a role for monitoring drug treatment coverage between less frequent, but more costly, probability sample surveys.