Search

We investigated a gastrointestinal illness cluster among persons who attended a baseball tournament (200 teams) during July 2015. We interviewed representatives of 19 teams; illness was reported among only the 9 (47%) teams that stayed at Hotel A (p.01). We identified 55 primary cases. A case-control study demonstrated that pool exposure at Hotel A was significantly associated with illness (odds ratio: 7.3; 95% confidence interval: 3.6, 15.2). Eight out of nine (89%) stool specimens tested were positive for Cryptosporidium, with C. hominis IfA12G1 subtype identified in two specimens. The environmental health assessment detected a low free available chlorine level, and pool water tested positive for E. coli and total coliforms. A possible diarrheal contamination event, substantial hotel pool use, and use of cyanuric acid might have contributed to this outbreak and magnitude. Aquatic facilities practicing proper operation and maintenance (e.g., following the Centers for Disease Control and Prevention’s Model Aquatic Health Code) can protect the public’s health.

Background Naegleria fowleri is a thermophilic ameba that is found in freshwater and causes primary amebic meningoencephalitis (PAM; 0–8 infections per year in the United States) when it enters the nose and migrates to the brain. Patient exposure to water containing the ameba typically occurs in warm freshwater lakes and ponds during recreational water activities. In September 2018, a 29-year-old man died of PAM after visiting a Texas inland surf park. Methods To determine water exposures, we reviewed medical records and conducted interviews with family and individuals who had traveled with the patient. To further investigate the inland surf park as a possible exposure source, we visited the facility and collected water, biofilm, and sediment samples from the surf park and other venues (water slides, lazy river, and cable park) within the facility. We assessed water sources and treatment practices, performed water quality tests, and tested for the presence of N. fowleri by culture and real-time PCR. Results Interviews revealed that the case-patient’s most probable water exposure in the 10 days before becoming ill occurred while surfing in an inland freshwater surf park where he fell off the surfboard into the water multiple times. The on-site investigation of the facility revealed a practice of manual chlorine treatment with monitoring, but no water filtering or record keeping to document water quality. Surf park water temperature was warm (25°C) and chlorine residual was negligible. N. fowleri was detected in 1 water and 1 sediment sample collected at the cable park venue, and viable thermophilic amebae were detected in all samples collected from the surf park, water slide, and cable park venues, as well from the sediment in the open-air groundwater reservoir feeding the venues. Conclusion This investigation documents a novel exposure in an inland surf park as the likely exposure causing PAM. Conditions in the surf park were conducive to amebic growth. Novel types of recreational water venues that do not meet traditional definitions of swimming pools, such as this surf park, might not meet the water quality standards for pools or similar treated venues. Clinicians and public health officials should remain vigilant for nontraditional exposures to water. Disclosures All authors: No reported disclosures.

In 1977, an outbreak of toxoplasmosis occurred among 37 persons associated with exposure to an indoor horse arena. Cat feces containing the organism were most likely stirred up when horses ran on the dirt floor, and were inhaled or ingested by riders and observers. After 25 or more years, we attempted to locate persons from the outbreak and offer them an eye examination. Of the 37 persons in the outbreak, 18 (49%) were located; four had died, and the remaining 14 agreed to an examination. Among the 14 persons examined, three (21%) were found to have lesions typical of toxoplasmic retinochoroiditis. If these three persons were the only ones with ocular disease among the 37 persons in the outbreak, the disease rate would still be high (8%). As a result of exposure to Toxoplasma gondii during this outbreak, a relatively high percentage of persons developed ocular disease.

The ability of chlorine dioxide (ClO2) to achieve 2-log inactivation of Cryptosporidium in drinking water has been documented. No studies have specifically addressed the effects of ClO2 on C. parvum oocyst infectivity in chlorinated recreational water venues (e.g., pools). The aim of this research was to determine the efficacy of ClO2 as an alternative to existing hyperchlorination protocols that are used to achieve a 3-log inactivation of Cryptosporidium in such venues. To obtain a 3-log inactivation of C. parvum Iowa oocysts, contact times of 105 and 128 min for a solution containing 5 mg/L ClO2 with and without the addition of 2.6 mg/L free chlorine, respectively, were required. Contact times of 294 and 857 min for a solution containing 1.4 mg/L ClO2 with and without the addition of 3.6 mg/L free chlorine, respectively, were required. The hyperchlorination control (21 mg/L free chlorine only) required 455 min for a 3-log inactivation. Use of a solution containing 5 mg/L ClO2 and solutions containing 5 or 1.4 mg/L ClO2 with the addition of free chlorine appears to be a promising alternative to hyperchlorination for inactivating Cryptosporidium in chlorinated recreational water venues, but further studies are required to evaluate safety constraints on use.

In July 2008, clusters of laboratory-confirmed cryptosporidiosis cases and reports of gastrointestinal illness in persons who visited a lake were reported to Tarrant County Public Health. In response, epidemiologic, laboratory, and environmental health investigations were initiated. A matched case-control study determined that swallowing the lake water was associated with illness (adjusted odds ratio = 16.3; 95% confidence interval: 2.5-infinity). The environmental health investigation narrowed down the potential sources of contamination. Laboratory testing detected Cryptosporidium hominis in case-patient stool specimens and Cryptosporidium species in lake water. It was only through the joint effort that epidemiologic, laboratory, and environmental health investigators could determine that1 human diarrheal fecal incidents in the lake likely led to contamination of the water. This same collaborative effort will be needed to develop and maintain an effective national Model Aquatic Health Code.

SUMMARYCryptosporidiumspecies have emerged as a major cause of outbreaks of diarrhoea and have been associated with consumption of contaminated recreational and drinking water and food as well as contact with infected attendees of child-care programmes. In August 2007, the Colorado Department of Public Health and Environment detected an increase in cryptosporidiosis cases over baseline values. We conducted a case-control study to assess risk factors for infection and collected stool specimens from ill persons for microscopy and molecular analysis. Laboratory-confirmed cases (n=47) were more likely to have swallowed untreated water from a lake, river, or stream [adjusted matched odds ratio (aOR) 8·0, 95% confidence interval (CI) 1·3–48·1], have had exposure to recreational water (aOR 4·6, 95% CI 1·4–14·6), or have had contact with a child in a child-care programme or in diapers (aOR 3·8, 95% CI 1·5–9·6). Although exposure to recreational water is commonly implicated in summertime cryptosporidiosis outbreaks, this study demonstrates that investigations of increased incidence of cases in summer should also examine other potential risk factors. This study emphasizes the need for public health education efforts that address the multiple transmission routes forCryptosporidiumand appropriate prevention measures to avoid future transmission.