Outbreaks of short-incubation ocular and respiratory illness following exposure to indoor swimming pools.

OBJECTIVES: Chlorination destroys pathogens in swimming pool water, but by-products of chlorination can cause human illness. We investigated outbreaks of ocular and respiratory symptoms associated with chlorinated indoor swimming pools at two hotels. MEASUREMENTS: We interviewed registered guests and companions who stayed at hotels X and Y within 2 days of outbreak onset. We performed bivariate and stratified analyses, calculated relative risks (RR), and conducted environmental investigations of indoor pool areas. RESULTS: Of 77 guests at hotel X, 47 (61%) completed questionnaires. Among persons exposed to the indoor pool area, 22 (71%) of 31 developed ocular symptoms [RR = 24; 95% confidence interval (CI), 1.5-370], and 14 (45%) developed respiratory symptoms (RR = 6.8; 95% CI, 1.0-47) with a median duration of 10 hr (0.25-24 hr). We interviewed 30 (39%) of 77 registered persons and 59 unregistered companions at hotel Y. Among persons exposed to the indoor pool area, 41 (59%) of 69 developed ocular symptoms (RR = 24; 95% CI, 1.5-370), and 28 (41%) developed respiratory symptoms (RR = 17; 95% CI, 1.1-260) with a median duration of 2.5 hr (2 min-14 days). Four persons sought medical care. During the outbreak, the hotel X's ventilation system malfunctioned. Appropriate water and air samples were not available for laboratory analysis. CONCLUSIONS AND RELEVANCE TO PROFESSIONAL PRACTICE: Indoor pool areas were associated with illness in these outbreaks. A large proportion of bathers were affected; symptoms were consistent with chloramine exposure and were sometimes severe. Improved staff training, pool maintenance, and pool area ventilation could prevent future outbreaks.

A waterborne outbreak of gastroenteritis with multiple etiologies among resort island visitors and residents: Ohio, 2004.

BACKGROUND: The implementation of treated municipal water systems in the 20th century led to a dramatic decrease in waterborne disease in the United States. However, communities with deficient water systems still experience waterborne outbreaks. In August 2004, we investigated an outbreak of gastroenteritis on South Bass Island, Ohio, an island of 900 residents that is visited by >500,000 persons each year. METHODS: To identify the source of illness, we conducted a case-control study and an environmental investigation. A case was defined as diarrhea in a person who traveled to the island during the period from May 1 through 30 September 2004 and became ill within 2 weeks after the visit. Healthy travel companions served as matched control subjects. We also performed an environmental assessment and extensive testing of island water sources. RESULTS: Among the 1450 persons reporting illness, Campylobacter jejuni, norovirus, Giardia intestinalis, and Salmonella enterica serotype Typhimurium were identified in 16, 9, 3, and 1 persons, respectively. We interviewed 100 case patients and 117 matched control subjects. Case patients were more likely to drink water on the island than control subjects (68% vs. 35%; matched odds ratio, 4.3; 95% confidence interval, 2.2-9.3). Sampling of ground water wells indicated contamination with multiple fecal microbes, including Escherichia coli, C. jejuni, Salmonella species, and Giardia species. Irregularities in sewage disposal practices that could have contaminated the underground aquifer were noted. CONCLUSIONS: The combined epidemiological and environmental investigation indicated that sewage-contaminated ground water was the likely source of this large outbreak. Long-term changes to the island's water supply and sewage management infrastructure are needed.

Invasive Enterobacter sakazakii disease in infants.

Enterobacter sakazakii kills 40%-80% of infected infants and has been associated with powdered formula. We analyzed 46 cases of invasive infant E. sakazakii infection to define risk factors and guide prevention and treatment. Twelve infants had bacteremia, 33 had meningitis, and 1 had a urinary tract infection. Compared with infants with isolated bacteremia, infants with meningitis had greater birthweight (2,454 g vs. 850 g, p = 0.002) and gestational age (37 weeks vs. 27.8 weeks, p = 0.02), and infection developed at a younger age (6 days vs. 35 days, p<0.001). Among meningitis patients, 11 (33%) had seizures, 7 (21%) had brain abscess, and 14 (42%) died. Twenty-four (92%) of 26 infants with feeding patterns specified were fed powdered formula. Formula samples associated with 15 (68%) of 22 cases yielded E. sakazakii; in 13 cases, clinical and formula strains were indistinguishable. Further clarification of clinical risk factors and improved powdered formula safety is needed.