Infection risks of city canal swimming events in the Netherlands in 2016.

<h4>Introduction</h4>Swimming events in city canals are gaining popularity in the Netherlands, even though canal water is usually not officially designated for recreational use. Knowledge regarding the risk of infection after swimming in canals is limited. An outbreak was reported in 201...

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Main Authors: A D Hintaran, S J Kliffen, W Lodder, R Pijnacker, D Brandwagt, A K van der Bij, E Siedenburg, G J B Sonder, E B Fanoy, R E Joosten
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2018-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0200616&type=printable
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author A D Hintaran
S J Kliffen
W Lodder
R Pijnacker
D Brandwagt
A K van der Bij
E Siedenburg
G J B Sonder
E B Fanoy
R E Joosten
author_facet A D Hintaran
S J Kliffen
W Lodder
R Pijnacker
D Brandwagt
A K van der Bij
E Siedenburg
G J B Sonder
E B Fanoy
R E Joosten
author_sort A D Hintaran
collection DOAJ
description <h4>Introduction</h4>Swimming events in city canals are gaining popularity in the Netherlands, even though canal water is usually not officially designated for recreational use. Knowledge regarding the risk of infection after swimming in canals is limited. An outbreak was reported in 2015 following a canal swimming event in Utrecht, the Netherlands. Local governments were concerned about the health risks of such events. In order to assess the safety of canal swimming, the Public Health Service (PHS) prospectively investigated two city canal swimming events in 2015. In 2016, we repeated this study, aiming to prospectively determine the risks of infection during two urban swimming events, the Utrecht SingelSwim 2016 (USS) and the Amsterdam City Swim 2016 (ACS).<h4>Methods</h4>We sent online questionnaires to 271 USS participants and 2697 ACS participants, concerning personal characteristics, symptoms, and exposure. Participants were asked to forward the questionnaire to three relatives, i.e., non-exposed. We analyzed water samples from the USS venue taken during the event, as well as stool samples of USS participants with acute gastrointestinal illness (AGI). AGI was defined as diarrhea and/or vomiting within seven days after the event. We calculated adjusted risk ratios (RR) for AGI in the exposed group compared with non-exposed respondents, using binomial regression models.<h4>Results</h4>The questionnaire was returned by 160 USS participants (exposed) (59%) and 40 non-exposed relatives. Five percent of the exposed (n = 17) and 3% of non-exposed (n = 1) reported AGI (RR = 1.69; 95% CI: 0.23-12.46). Norovirus genogroup II was detected in two of six USS water samples and in none of the three stool samples. In one of three stool samples, rotavirus was detected. The questionnaire was returned by 1169 ACS participants (exposed) (43%) and 410 non-exposed relatives. Six percent of the exposed (n = 71) and 1% of non-exposed (n = 5) reported AGI (RR 4.86; 95% CI: 1.98-11.97).<h4>Conclusion</h4>Results of the ACS event showed a higher risk for AGI among the exposed, indicating that participants of events in urban canals in the Netherlands could be at a higher risk for AGI than those not participating. The inconclusive results from the USS are likely due to the small sample size. Swimming in non-monitored open water can bring health risks and more knowledge about environmental and human risk factors helps reduce the risk by being able to more specifically advise organizations and governments.
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spelling doaj.art-5e0531fd42924762ab154c92fbb609e22025-02-28T05:31:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032018-01-01137e020061610.1371/journal.pone.0200616Infection risks of city canal swimming events in the Netherlands in 2016.A D HintaranS J KliffenW LodderR PijnackerD BrandwagtA K van der BijE SiedenburgG J B SonderE B FanoyR E Joosten<h4>Introduction</h4>Swimming events in city canals are gaining popularity in the Netherlands, even though canal water is usually not officially designated for recreational use. Knowledge regarding the risk of infection after swimming in canals is limited. An outbreak was reported in 2015 following a canal swimming event in Utrecht, the Netherlands. Local governments were concerned about the health risks of such events. In order to assess the safety of canal swimming, the Public Health Service (PHS) prospectively investigated two city canal swimming events in 2015. In 2016, we repeated this study, aiming to prospectively determine the risks of infection during two urban swimming events, the Utrecht SingelSwim 2016 (USS) and the Amsterdam City Swim 2016 (ACS).<h4>Methods</h4>We sent online questionnaires to 271 USS participants and 2697 ACS participants, concerning personal characteristics, symptoms, and exposure. Participants were asked to forward the questionnaire to three relatives, i.e., non-exposed. We analyzed water samples from the USS venue taken during the event, as well as stool samples of USS participants with acute gastrointestinal illness (AGI). AGI was defined as diarrhea and/or vomiting within seven days after the event. We calculated adjusted risk ratios (RR) for AGI in the exposed group compared with non-exposed respondents, using binomial regression models.<h4>Results</h4>The questionnaire was returned by 160 USS participants (exposed) (59%) and 40 non-exposed relatives. Five percent of the exposed (n = 17) and 3% of non-exposed (n = 1) reported AGI (RR = 1.69; 95% CI: 0.23-12.46). Norovirus genogroup II was detected in two of six USS water samples and in none of the three stool samples. In one of three stool samples, rotavirus was detected. The questionnaire was returned by 1169 ACS participants (exposed) (43%) and 410 non-exposed relatives. Six percent of the exposed (n = 71) and 1% of non-exposed (n = 5) reported AGI (RR 4.86; 95% CI: 1.98-11.97).<h4>Conclusion</h4>Results of the ACS event showed a higher risk for AGI among the exposed, indicating that participants of events in urban canals in the Netherlands could be at a higher risk for AGI than those not participating. The inconclusive results from the USS are likely due to the small sample size. Swimming in non-monitored open water can bring health risks and more knowledge about environmental and human risk factors helps reduce the risk by being able to more specifically advise organizations and governments.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0200616&type=printable
spellingShingle A D Hintaran
S J Kliffen
W Lodder
R Pijnacker
D Brandwagt
A K van der Bij
E Siedenburg
G J B Sonder
E B Fanoy
R E Joosten
Infection risks of city canal swimming events in the Netherlands in 2016.
PLoS ONE
title Infection risks of city canal swimming events in the Netherlands in 2016.
title_full Infection risks of city canal swimming events in the Netherlands in 2016.
title_fullStr Infection risks of city canal swimming events in the Netherlands in 2016.
title_full_unstemmed Infection risks of city canal swimming events in the Netherlands in 2016.
title_short Infection risks of city canal swimming events in the Netherlands in 2016.
title_sort infection risks of city canal swimming events in the netherlands in 2016
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0200616&type=printable
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