Splash Parks and Cryptosporidiosis
Splash Parks and Cryptosporidiosis
Abstract & Commentary
By Maria D. Mileno, MD
Dr. Mileno is Director, Travel Medicine, The Miriam Hospital, Associate Professor of Medicine, Brown University, Providence, RI.
Dr. Mileno reports no financial relationships relevant to this field of study.
Synopsis: An outbreak of cryptosporidiosis involving at least 50 people occurred during the summer of 2007 associated with a brand new municipal splash park in Idaho. Lessons learned from this thorough CDC investigation apply to facilities that are now appearing for year-round splashing.
Source: Jue R, Smalz T, Carter K, et al. Outbreak of Cryptosporidiosis associated with a splash park — Idaho, 2007. MMWR June 2009;58(22);615-618.
A complaint to Idaho's Central District Health Department of several ill persons with watery diarrhea consistent with cryptosporidiosis triggered an investigation of splash park visitors who attended reservation-only gatherings. Many more individuals who attended these parks could not be traced. The findings represent a small percentage of daily attendees, and likely the tip of an iceberg with regard to illness. Splash parks generally offer several interactive water features that spray, splash, or pour water on visitors, without pools or standing water. Usually, the source of water is a municipal water system, and it flows from the features onto water-impermeable surfaces, then through drains for re-circulation through high-flow sand filters back into the water features system. Splash park design, construction, and operation are not regulated by the Idaho pool code.
Of 20 persons interviewed in an initial investigation, 12 reported gastrointestinal illness that began 6-11 days after exposure. All 12 ill persons reported exposure to the "splash feature" water and 6 reported exposure to a nearby drinking fountain. To locate any additional cases and further understand this outbreak, Idaho's Central District Health Department (CDHD) and the Idaho Department of Health and Welfare (IDHW) interviewed splash park visitors who attended reservation-only gatherings. Twelve groups totaling 600 visitors were identified, and the first 154 respondents contacted were interviewed. These represented 75%, or 9 of 12, reservation parties.
A clinical case definition included the following criteria: three or more loose stools in 24 hours or four or more symptoms consistent with gastroenteritis, i.e., abdominal cramps, nausea, vomiting, fever, or body aches occurring within 1-12 days after visiting the municipal park. A confirmed case included a positive IFA stool test for Cryptosporidium in an ill person. Persons who did not meet either case definition were identified as non-ill park visitors. Participants completed a standardized telephone questionnaire. Of 154 respondents representing 51 separate households and 12 different days of exposure, 32% had illness that met clinical or confirmed case definition. Fifty-two percent were males, and median age was 7 years old (range form 10 months to 58 years). Illness onset ranged from July 28 to Aug. 20, and median time from exposure to onset of illness was 6 days, with a range between 1 to 14 days. One patient with a confirmed case reported splash park exposure on August 1 and illness by August 15. The median duration of illness was 3 days among 29 patients whose illness was resolved at the time of the interview. No hospitalizations or deaths occurred, and the most common symptoms reported were diarrhea 46%, vomiting 64%, abdominal cramps 62%, nausea 62%, fever 52%, headache 46%, and body aches 40%. No treatment information was available.
A retrospective cohort analysis was used to identify risk factors for illness. Patients were more likely than non-ill visitors to have been exposed to splash-feature water only. Patients also were more likely to report exposure to both the splash water features and the adjacent drinking fountain water than were the non-ill visitors.
An environmental site investigation was begun Aug. 9. Young children were the predominant users of the splash park, and diapered children frequently sat on top of splash features. Neither soap nor showers were available in nearby restrooms, and there were no public health education signs posted at the park. The water was chlorinated and there was no standing water. Water drained from a concrete deck, passed through a high-flow sand filter, and was chlorinated before recirculation through several splash features. Water samples from the splash park were analyzed for total coliform bacteria and Escherichia coli. The EPA methodology for detection of Cryptosporidium and Giardia by use of concentration immunomagnetic separation and immunofluoresence assay microscopy identified C. hominis in samples of the high-flow sand filter backwash and the adjacent drinking fountain by polymerase chain reaction-restriction length polymorphism analysis of DNA extracted from microscopy positive slides. Oocysts in both samples were subtyped further by DNA sequencing. Two Cryptosporidium isolates from patients also were genotyped and subtyped. The park was closed on Aug. 17, and the drinking fountains were turned off Aug. 23. Investigation found no source for drinking waste contamination; however, after the outbreak, two return back-flow-prevention devices designed to prevent retrograde flow of splash park water into municipal water lines failed inspection and were replaced. A decrease in water pressure could have allowed a potential retrograde flow of contaminated water into the municipal water line. Repeat testing of the drinking fountain water and upstream water subsequently showed no Cryptosporidium oocysts.
Commentary
The outbreak described in this report occurred at a newly constructed facility with design and operations issues that the department of health staff might have corrected were they consulted in advance of opening. Splash parks should be considered within the pool code for state and local governments to share universal systems approaches for public safety. Supplemental disinfection technology with ultraviolet light treatment, appropriate hygiene facilities, attendants to monitor appropriate pool hygiene etiquette, and postings of educational signs regarding the prevention of recreational water illness all accompanied the reopening of this facility. Cryptosporidia are chlorine-resistant parasites that can result in illness after ingestion of as few as 10 oocysts. They can remain infectious for up to 6 months in moist environments. Initial contamination of splash park water by an ill visitor likely caused persistent contamination of the splash park system and resulted in ongoing transmission. While cryptosporidiosis is an opportunistic infection that can cause severe illness and dehydration in HIV-infected individuals, immunocompetent persons also may endure significant morbidity from cryptosporidiosis in a somewhat more self-limited manner.
On a broader scale, sporadic cases of infectious intestinal disease captured by an alert system in Scotland shed light on outbreaks associated with travel to particular countries, including an outbreak due to cryptosporidiosis. Although most countries in Europe and North America have surveillance systems for outbreaks of either all infectious intestinal diseases or food-borne diseases, few capture information on outbreaks in which infection may have been acquired abroad. Out of 319 potential outbreaks, there were 51 (16%) potential protozoal outbreaks; 48/51 (94%) due to Cryptosproidium sp. and 3/51 (6%) due to Giardia sp. Among the potential outbreaks of Cryptosporidium sp., 33/48 (69%) were associated with travel to Spain and 7/48 (15%) were associated with travel to Turkey. One mixed outbreak involved 3 pathogens: norovirus, Cryptosporidium sp. and Shigella sonnei associated with travel to the Dominican Republic. The largest outbreak identified during the period of study in this descriptive paper was an outbreak of Cryptosporidium sp. associated with a hotel in Majorca. Health Protection of Scotland first reported the outbreak based on one case, and other cases were rapidly identified in Scotland. A swimming pool, the suspected source of infection, was promptly closed, possibly limiting the size of the outbreak. Swimming pools and water parks, in particular, were linked with outbreaks of cryptosporidiosis. This system of worldwide potential outbreak detection links cases based on the laboratory isolation of a pathogen and the completion of an enteric diseases questionnaire is a model worth reviewing. It offers a timely, comprehensive finger-on-the-pulse for travel-related intestinal infectious disease.
References
- Mandell. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases, 7th edition, Churchill Livingstone, Elsevier, 2009. Chapter 283, Cryptosporidium Species.
- Centers for Disease Control and Prevention. Outbreak of gastroenteritis associated with an interactive water fountain at a beachside park — Florida, 1999. MMWR 2000;49:565-8.
- Schaffzin JK, Keithly J, Johnson G, et al. Large outbreak of cryptosporidiosis associated with a recreational water spraypark — New York, 2005 [Abstract]. Proceedings of the 55th Annual Conference of the Epidemic Intelligence Service; 2006; Atlanta, GA: US Department of Health and Human Services, CDC; 2006.
- CDC. Surveillance for waterborne-disease outbreaks associated with recreational water — United States, 2001-2002. MMWR 2004;53(No. SS-8).
- Smith-Palmer A, and Cowden JM. Overseas outbreaks of infectious intestinal disease identified in Scotland, 2003 to 2007. J Travel Med 2009;16:322-327.
- Galmes A, Nicolau A, Arbona G, et al. Cryptosporidium outbreak in British tourists who stayed at a hotel in Majoca, Spain. Euro Surveill 2003; 7.
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.