METHODS: Standardized interviews were conducted with a convenience sample of 19 teams to establish illness scope, followed by a case-control study among team and non-team guests of Hotel A using team rosters and hotel records. We defined a probable case as vomiting or diarrhea (≥3 stools/24 hours) in a person who stayed at Hotel A during July 15–August 4, 2015; confirmed cases had Cryptosporidium detected in stool specimens. We molecularly typed Cryptosporidium specimens and conducted an environmental assessment of Hotel A’s pool.
RESULTS: Of teams interviewed, illness was reported only among 9 teams that stayed at Hotel A (P <0.01). We identified 63 cases (8 laboratory confirmed) and 190 control subjects. Case-patients were aged 3–65 years (median 13 years; 70% male). Pool exposure was significantly associated with illness (odds ratio: 7.0; 95% confidence interval: 3.5–14.2). Cryptosporidium hominis subtype IfA12G1 was identified in 2 specimens. Hotel guests reported cloudy water and overcrowded conditions, and three guests reported swimming while ill with diarrhea. Environmental assessment demonstrated Escherichia coli and total coliforms in pool water as well as low chlorine levels, indicating poor maintenance and prompting pool closure.
CONCLUSIONS: A diarrheal contamination event and high utilization of the hotel pool likely contributed to this outbreak and its magnitude. Aquatic facilities should practice correct maintenance following available prevention tools (e.g., CDC’s Model Aquatic Health Code).