An outbreak of cryptosporidiosis at a swimming club – can rapid field epidemiology limit the spread of illness?

McCann, Rosemary; Jones, Russell; Snow, Jamie; Cleary, Paul; Burgess, Stephen; Bothra, Vinay; Chalmers, Rachel M.

doi:10.1017/s0950268813001143

Cited by 17 publications

(18 citation statements)

References 7 publications

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“…We did not find any evidence for food vehicles playing a role in this outbreak. Swimming pools have been frequently indicted as sources of infection during outbreaks of cryptosporidiosis [ 33 - 35 ]. Moreover, pool-to-pool transfer of oocysts by diarrhoeal swimmers has been described [ 36 ].…”

Section: Discussionmentioning

confidence: 99%

Outbreak of cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013

Gertler

Dürr²,

Renner

et al. 2015

BMC Infect Dis

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BackgroundDuring weeks 32–33, 2013, 24 cases of cryptosporidiosis were notified in the city of Halle (annual mean 2008–2012: 9 cases). We investigated the outbreak to identify the source and recommend control measures, considering that between weeks 23–25 the river Saale which flows through the city centre overflowed the floodplain, parts of the city centre and damaged sewage systems.MethodsWe defined a case as a resident of Halle with gastroenteritis, Cryptosporidium-positive stool and disease onset weeks 27 through 47. In a case–control study among kindergarten children, we compared cases and controls regarding environmental exposure, use of swimming pools, zoo visits and tap water consumption 14 days pre-onset or a corresponding 14-days-period (controls) and adjusted for residence. Stool specimens were tested by microscopy and PCR, and Cryptosporidium DNA was sequenced. Samples from public water system, swimming pools and river Saale were examined for Cryptosporidium oocysts (microscopy and PCR).ResultsOverall, 167 cases were detected, 40/167 (24%) were classified as secondary cases. First disease onsets occurred during week 29, numbers peaked in week 34 and started to decrease in week 36. Median age was 8 years (range: 0–77). Compared to controls (n = 61), cases (n = 20) were more likely to report visits to previously flooded areas (OR: 4.9; 95%-CI: 1.4-18) and the zoo (OR: 2.6; 95%-CI: 0.9-7.6). In multivariable analysis visits to the floodplain remained the sole risk factor (OR: 5.5; 95%-CI: 1.4-22). Only C.hominis of a single genotype (IbA9G2) was detected in stools. Oocysts were detected in samples from the river, two local lakes and three public swimming pools by microscopy, but not in the public water supply.ConclusionsEvidence suggests that activities in the dried out floodplain led to infection among children. Secondary transmissions may be involved. Consequently, authorities recommended to avoid playing, swimming and having picnics in the flood-affected area. Health authorities should consider the potential health risks of long-term surviving parasites persisting on flooded grounds and in open waters even several weeks after the flooding and of bathing places close to sewage spill-overs. Preventive measures comprise water sampling (involving parasites), information of the public and prolonged closures of potentially contaminated sites.

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Section: Discussionmentioning

confidence: 99%

Outbreak of cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013

Gertler

Dürr²,

Renner

et al. 2015

BMC Infect Dis

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“…Others who have investigated recreational water–associated outbreaks of cryptosporidiosis have also called for proactive response to these outbreaks [22, 23]. Both Coetzee et al and McCann et al .…”

Section: Discussionmentioning

confidence: 99%

“…Others [22, 23] who have investigated recreational water-associated outbreaks of cryptosporidiosis have also called for proactive response to these outbreaks. These studies advocate for rapid field epidemiology to direct implementation of control measures in response to recreational water-associated outbreaks of cryptosporidiosis.…”

Section: Discussionmentioning

confidence: 99%

Preventing community-wide transmission ofCryptosporidium: a proactive public health response to a swimming pool-associated outbreak – Auglaize County, Ohio, USA

Cope¹,

Prosser

Nowicki

et al. 2015

Epidemiol. Infect.

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Summary The incidence of recreational water–associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues, (e.g., pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g., child care facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to Pool A. Within 5 days of the first case being reported, Pool A was hyperchlorinated to achieve 99.9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in Pool A (matched odds ratio 121.7, 95% confidence interval 27.4–∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.

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“…the aetiological agent in 63% of outbreaks 6 . Outbreaks of cryptosporidiosis have been associated with aquatic facilities including swimming pools 7–23 and splash parks 24–27 worldwide. In Australia between 2001 and 2007, Cryptosporidium spp.…”

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confidence: 99%

Preventing and controlling spp. in aquatic facilities: environmental health practitioners’ experiences in Victoria, Australia

Cullinan

McLean

Dunn

2020

Australian and New Zealand Journal of Public Health

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Objective:To identify barriers and enablers to preventing and controlling Cryptosporidium spp. in aquatic facilities as perceived by environmental health practitioners (EHPs). Methods:A qualitative, constructivist study with a purposive sample of seven EHPs from Victoria, Australia, was conducted. A focus group discussion was guided by a semi-structured interview schedule using open-ended questions. The audio-recorded focus group was transcribed verbatim and analysed using thematic analysis.Results: Five themes represented the perceived barriers and enablers: i) pool water testing methods; ii) resources and training for EHPs; iii) knowledge and behaviour of aquatic facility operators and swimming pool users; iv) regulation; and v) aquatic facility and swimming pool design. Two key barriers within these themes included aquatic facility regulation and unhealthy swimming behaviours. Conclusions:Several barriers and enablers to preventing and controlling Cryptosporidium spp. in aquatic facilities were perceived by EHPs. Suggestions to overcome perceived barriers were also identified. Further research is required to determine the impact of these findings on the incidence of cryptosporidiosis associated with aquatic facilities. Implications for public health:The findings contribute to a greater understanding of the barriers and enablers to Cryptosporidium spp. prevention and control in aquatic facilities, which may improve the effectiveness of current prevention and control strategies.

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An outbreak of cryptosporidiosis at a swimming club – can rapid field epidemiology limit the spread of illness?

Cited by 17 publications

References 7 publications

Outbreak of cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013

Outbreak of cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013

Preventing community-wide transmission ofCryptosporidium: a proactive public health response to a swimming pool-associated outbreak – Auglaize County, Ohio, USA

Preventing and controlling spp. in aquatic facilities: environmental health practitioners’ experiences in Victoria, Australia

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