Cryptosporidium and Giardia in recreational water in Belgium Md. Amimul Ehsan, Stijn Casaert, Bruno Levecke, Liesbet Van Rooy, Joachim Pelicaen, Anne Smis, Joke De Backer, Bart Vervaeke, Sandra De Smedt, Filip Schoonbaert, Saskia Lammens, Thierry Warmoes, Thomas Geurden and Edwin Claerebout ABSTRACT The objective of this study was to investigate the presence of Cryptosporidium and Giardia in different recreational water bodies in Belgium and to estimate the infection risk associated with swimming and other recreational activities. Cryptosporidium oocysts and/or Giardia cysts were detected in three out of 37 swimming pools, seven out of 10 recreational lakes, two out of seven splash parks and four out of 16 water fountains. In the swimming pools no infection risk for Cryptosporidium could be calculated, since oocysts were only detected in filter backwash water. The risk of Giardia infection in the swimming pools varied from 1.13 × 10 À6 to 2.49 × 10 À6 per swim per person. In recreational lakes, the infection risk varied from 2.79 × 10 À5 to 5.74 × 10 À5 per swim per person for Cryptosporidium and from 7.04 × 10 À5 to 1.46 × 10 À4 for Giardia. For other outdoor water recreation activities the estimated infection risk was 5.71 × 10 À6 for Cryptosporidium and 1.47 × 10 À5 for Giardia. However, most positive samples in the recreational lakes belonged to species/genotypes that are either animal-specific or predominantly found in animals. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection. The infection risk of Giardia infection during a 3.5-minute visit to a splash park for children equalled 1.68 × 10 À4 . Md. Amimul Ehsan † Stijn Casaert † Bruno Levecke Thomas Geurden Edwin Claerebout (corresponding author) Laboratory for Parasitology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium E-mail: edwin.claerebout@ugent.be Liesbet Van Rooy Anne Smis Joke De Backer Filip Schoonbaert Agency for Care and Health, Flemish Ministry for Welfare, Public Health and Family, Brussels, Belgium Joachim Pelicaen Bart Vervaeke Sandra De Smedt Saskia Lammens Thierry Warmoes Flemish Environment Agency, Erembodegem, Belgium † Contributed equally to this work. Key words | Belgium, Cryptosporidium, Giardia, recreational water, risk assessment INTRODUCTION Cryptosporidium and Giardia are important parasites in the aetiology of diarrhoea worldwide. In industrialised countries Cryptosporidium spp. are detected in up to 54.2% and Giar- dia spp. in up to 74.4% (Homan & Mank ; Geurden et al. ) of immunocompetent patients with diarrhoea. In non-outbreak-related cases of diarrhoea in Belgian patients, Giardia was identified as the second most prevalent pathogen. In the same study Cryptosporidium was also within the five most commonly detected pathogens, indicating that both parasites occur frequently in patients with gastro-intesti- nal symptoms (Geurden et al. ). In Belgium, the national incidence of cryptosporidiosis and giardiosis is 2.5 and 10.8 per 100,000 inhabitants, respectively, with the highest inci- dence in children (<5 years of age) and young adults (25– 44 years old) (Wetenschappelijk Instituut Volksgezondheid [WIV] ). Transmission of Cryptosporidium spp. and Giardia spp. occurs from either humans or animals by the faecal-oral route. In humans worldwide C. hominis and C. parvum are the most commonly detected Cryptosporidium species. C. hominis is human-specific, while C. parvum infects rumi- nants and humans. Giardia duodenalis assemblage A and B are responsible for giardiosis in humans, and are also found in a wide range of mammals. Within assemblage A, 870 © IWA Publishing 2015 Journal of Water and Health | 13.3 | 2015 doi: 10.2166/wh.2015.268 Downloaded from https://iwaponline.com/jwh/article-pdf/13/3/870/394974/jwh0130870.pdf by guest on 10 June 2020