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is a leading global cause of waterborne disease, with many reported outbreaks related to main water supplies. In August 2019, an outbreak of cryptosporidiosis involving 80 cases occurred among 114 vacationers in a small municipality located in the Tuscan-Emilian Apennines, north-eastern Italy. After excluding a potential food-borne outbreak, the epidemiological investigation focussed on the hypothesis of a waterborne outbreak. This was confirmed by the finding of oocysts in stools of the cases and in water samples from the municipal water network. Molecular characterisation revealed the zoonotic species as the causative agent. A single subtype (IIdA25G1) was found among all cases, and in one of two positive water samples. The municipality’s water supply used spring water that only received a disinfection treatment insufficient to inactivate the parasite. Possible entry means into the water mains were found through further environmental investigations. As these types of water supplies are particularly vulnerable to various environmental factors, a control system based on the risk assessment of each phase of the water supply chain is required to guarantee water safety. Effective methods for detection of protozoan pathogens, which are generally excluded from routine water supply analysis, should be applied.


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  1. Moreira NA, Bondelind M. Safe drinking water and waterborne outbreaks. J Water Health. 2017;15(1):83-96.  https://doi.org/10.2166/wh.2016.103  PMID: 28151442 
  2. Pane S, Putignani L. Cryptosporidium: Still Open Scenarios. Pathogens. 2022;11(5):515.  https://doi.org/10.3390/pathogens11050515  PMID: 35631036 
  3. Gerace E, Lo Presti VDM, Biondo C. Cryptosporidium infection: epidemiology, pathogenesis, and differential diagnosis. Eur J Microbiol Immunol (Bp). 2019;9(4):119-23.  https://doi.org/10.1556/1886.2019.00019  PMID: 31934363 
  4. Pinto DJ, Vinayak S. Cryptosporidium: host-parasite interactions and pathogenesis. Curr Clin Microbiol Rep. 2021;8(2):62-7.  https://doi.org/10.1007/s40588-021-00159-7  PMID: 33585166 
  5. Zahedi A, Ryan U. Cryptosporidium - An update with an emphasis on foodborne and waterborne transmission. Res Vet Sci. 2020;132:500-12.  https://doi.org/10.1016/j.rvsc.2020.08.002  PMID: 32805698 
  6. Betancourt W. Cryptosporidium spp. In: J.B. Rose and B. Jiménez-Cisneros, (eds) 2019, Water and Sanitation for the 21st Century: Health and Microbiological Aspects of Excreta and Wastewater Management (Global Water Pathogen Project). (R. Fayer and W. Jakubowski (eds), Part 3: Specific Excreted Pathogens: Environmental and Epidemiology Aspects - Section 3: Protists), Michigan State University, E. Lansing, MI, UNESCO.  https://doi.org/10.14321/waterpathogens.33 
  7. Okhuysen PC, Chappell CL, Crabb JH, Sterling CR, DuPont HL. Virulence of three distinct Cryptosporidium parvum isolates for healthy adults. J Infect Dis. 1999;180(4):1275-81.  https://doi.org/10.1086/315033  PMID: 10479158 
  8. Adeyemo FE, Singh G, Reddy P, Bux F, Stenström TA. Efficiency of chlorine and UV in the inactivation of Cryptosporidium and Giardia in wastewater. PLoS One. 2019;14(5):e0216040.  https://doi.org/10.1371/journal.pone.0216040  PMID: 31083664 
  9. Ma JY, Li MY, Qi ZZ, Fu M, Sun TF, Elsheikha HM, et al. Waterborne protozoan outbreaks: An update on the global, regional, and national prevalence from 2017 to 2020 and sources of contamination. Sci Total Environ. 2022;806(Pt 2):150562.  https://doi.org/10.1016/j.scitotenv.2021.150562  PMID: 34852432 
  10. Widerström M, Schönning C, Lilja M, Lebbad M, Ljung T, Allestam G, et al. Large outbreak of Cryptosporidium hominis infection transmitted through the public water supply, Sweden. Emerg Infect Dis. 2014;20(4):581-9.  https://doi.org/10.3201/eid2004.121415  PMID: 24655474 
  11. Rehn M, Wallensten A, Widerström M, Lilja M, Grunewald M, Stenmark S, et al. Post-infection symptoms following two large waterborne outbreaks of Cryptosporidium hominis in Northern Sweden, 2010-2011. BMC Public Health. 2015;15(1):529.  https://doi.org/10.1186/s12889-015-1871-6  PMID: 26041728 
  12. Garcia LS, Bruckner DA, Brewer TC, Shimizu RY. Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens. J Clin Microbiol. 1983;18(1):185-90.  https://doi.org/10.1128/jcm.18.1.185-190.1983  PMID: 6193138 
  13. Istituto Superiore di Sanità. Linee guida per la valutazione e gestione del rischio nella filiera delle acque destinate al consumo umano secondo il modello dei Water Safety Plans. Rapporti ISTISAN 14/21: 2014. [Guideline for risk assessment and management within the drinking water chain according to Water Safety Plans]. Roma: Istituto Superiore di Sanità; 2014. Italian. Available from: https://www.iss.it/documents/20126/45616/14_21_web.pdf/68c7940a-acd9-3569-fe07-af3fac298a79?t=1581095415282
  14. International Organization for Standardization (ISO). ISO 15553:2006. Water quality — Isolation and identification of Cryptosporidium oocysts and Giardia cysts from water. Geneva: ISO. Available from: https://www.iso.org/obp/ui/#iso:std:iso:15553:en
  15. European Commission. Directive 98/83/EC on the quality of water intended for human consumption. Official Journal of the European Communities L330/32; December 5, 1998. Available from: http://extwprlegs1.fao.org/docs/pdf/eur18700.pdf
  16. International Organization for Standardization (ISO). ISO 9308-2: 2012. Water quality - Enumeration of Escherichia coli and coliform bacteria - Part 2: Most probable number method. Geneva: ISO. Available from: http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=52246
  17. IDEXX Laboratories, Inc. IDX 33/03-10/13. Enterolert-DW / Quanti-Tray. Certifiée sous le n° d’attestation avec pour fin de validitè le 10 oct 2017. Enterolert (Idexx). [Enterolert-DW / Quanti-Tray Validated for the enumeration of intestinal enterococci.] French. Available from: https://nf-validation.afnor.org/wp-content/uploads/sites/2/2014/03/IDX-33-03-10-13_en.pdf
  18. International Organization for Standardization (ISO). ISO 16266-2:2018(en). Water quality — Detection and enumeration of Pseudomonas aeruginosa — Part 2: Most probable number method. Geneva: ISO. Available from: https://www.iso.org/standard/70091.html
  19. UNI EN ISO 6222:2001. Qualità dell’acqua. Valutazione quantitativa dei microrganismi vitali. Conteggio delle colonie per inoculo su terreno agarizzato. [UNI EN ISO 6222:2001. Water quality - Enumeration of culturable micro-organisms - Colony count by inoculation in a nutrient agar culture medium]. Italian.
  20. International Organization for Standardization (ISO). ISO 14189:2013(en). Water quality — Enumeration of Clostridium perfringens — Method using membrane filtration. Geneva: ISO. Available from: https://www.iso.org/obp/ui/#iso:std:iso:14189:ed-1:v1:en
  21. Ottaviani M, Bonadonna L, editors. Roma: Istituto Superiore di Sanità, Rapporti ISTISAN 07/31: 2007. Available from: https://www.salute.gov.it/imgs/C_17_pubblicazioni_2277_allegato.pdf
  22. Ryan U, Xiao L, Read C, Zhou L, Lal AA, Pavlasek I. Identification of novel Cryptosporidium genotypes from the Czech Republic. Appl Environ Microbiol. 2003;69(7):4302-7.  https://doi.org/10.1128/AEM.69.7.4302-4307.2003  PMID: 12839819 
  23. Strong WB, Gut J, Nelson RG. Cloning and sequence analysis of a highly polymorphic Cryptosporidium parvum gene encoding a 60-kilodalton glycoprotein and characterization of its 15- and 45-kilodalton zoite surface antigen products. Infect Immun. 2000;68(7):4117-34.  https://doi.org/10.1128/IAI.68.7.4117-4134.2000  PMID: 10858229 
  24. Italia. Decreto legislativo 2 febbraio 2001, n. 31. Attuazione della direttiva 98/83/CE relativa alla qualità delle acque destinate al consumo umano. Gazzetta Ufficiale - Serie Generale n. 52, 3 marzo 2001. [LEGISLATIVE DECREE 2 February 2001, n. 31 Implementation of Directive 98/83 / EC relating to the quality of water intended for human consumption. (GU General Series n.52 of 03-03-2001 - Ordinary Suppl. N. 41).] Italian. Available from: https://www.gazzettaufficiale.it/eli/id/2001/03/03/001G0074/sg
  25. World Health Organization (WHO) and International Water Association (IWA). ‎Water safety plan manual: Step by-step risk management for drinking-water suppliers. Geneva: World Health Organization; 2009. Available from: https://apps.who.int/iris/bitstream/handle/10665/75141/9789241562638_eng.pdf?sequence=1&isAllowed=y
  26. European Centre for Disease Prevention and Control (ECDC). Cryptosporidiosis - Annual epidemiological report for 2018. Stockholm: ECDC; 2021. Available from: https://www.ecdc.europa.eu/en/publications-data/cryptosporidiosis-annual-epidemiological-report-2018
  27. Cacciò SM, Sannella AR, Mariano V, Valentini S, Berti F, Tosini F, et al. A rare Cryptosporidium parvum genotype associated with infection of lambs and zoonotic transmission in Italy. Vet Parasitol. 2013;191(1-2):128-31.  https://doi.org/10.1016/j.vetpar.2012.08.010  PMID: 22954678 
  28. Giangaspero A, Berrilli F, Brandonisio O. Giardia and Cryptosporidium and public health: the epidemiological scenario from the Italian perspective. Parasitol Res. 2007;101(5):1169-82.  https://doi.org/10.1007/s00436-007-0598-4  PMID: 17593392 
  29. Briancesco R, Della Libera S, Semproni M, Bonadonna L. Relationship between Cryptosporidium and microbiological water quality parameters in raw water. J Prev Med Hyg. 1999;40:39-42. Available from: https://www.academia.edu/17309676/Relationship_between_Cryptosporidium_and_microbiological_water_quality_parameters_in_raw_water
  30. Bonadonna L, Briancesco R, Ottaviani M, Veschetti E. Occurrence of Cryptosporidium oocysts in sewage effluents and correlation with microbial, chemical and physical water variables. Environ Monit Assess. 2002;75(3):241-52.  https://doi.org/10.1023/A:1014852201424  PMID: 12004978 
  31. Pignata C, Bonetta S, Bonetta S, Cacciò SM, Sannella AR, Gilli G, et al. Cryptosporidium oocyst contamination in drinking water: a case study in Italy. Int J Environ Res Public Health. 2019;16(11):2055.  https://doi.org/10.3390/ijerph16112055  PMID: 31185673 
  32. Briancesco R, Bonadonna L. An Italian study on Cryptosporidium and Giardia in wastewater, fresh water and treated water. Environ Monit Assess. 2005;104(1-3):445-57.  https://doi.org/10.1007/s10661-005-2282-4  PMID: 15932003 
  33. Giangaspero A, Cirillo R, Lacasella V, Lonigro A, Marangi M, Cavallo P, et al. Giardia and Cryptosporidium in inflowing water and harvested shellfish in a lagoon in Southern Italy. Parasitol Int. 2009;58(1):12-7.  https://doi.org/10.1016/j.parint.2008.07.003  PMID: 18760378 
  34. Pozio E, Rezza G, Boschini A, Pezzotti P, Tamburrini A, Rossi P, et al. Clinical cryptosporidiosis and human immunodeficiency virus (HIV)-induced immunosuppression: findings from a longitudinal study of HIV-positive and HIV-negative former injection drug users. J Infect Dis. 1997;176(4):969-75.  https://doi.org/10.1086/516498  PMID: 9333155 
  35. Cacciò SM, Chalmers RM. Human cryptosporidiosis in Europe. Clin Microbiol Infect. 2016;22(6):471-80.  https://doi.org/10.1016/j.cmi.2016.04.021  PMID: 27172805 
  36. Lamy M, Sanseverino I, Niegowska M, Lettieri T. Microbiological Parameters under the Drinking Water Directive. Current state of art on somatic coliphages and Clostridium perfringens and spores, EUR 29932 EN. Luxembourg: Publications Office of the European Union. ISBN 978-92-76-12593-8. Available from: https://op.europa.eu/en/publication-detail/-/publication/2795349d-7f8c-11ea-aea8-01aa75ed71a1/language-en
  37. Mason BW, Chalmers RM, Carnicer-Pont D, Casemore DP. A Cryptosporidium hominis outbreak in north-west Wales associated with low oocyst counts in treated drinking water. J Water Health. 2010;8(2):299-310.  https://doi.org/10.2166/wh.2009.184  PMID: 20154393 
  38. Quílez J, Torres E, Chalmers RM, Hadfield SJ, Del Cacho E, Sánchez-Acedo C. Cryptosporidium genotypes and subtypes in lambs and goat kids in Spain. Appl Environ Microbiol. 2008;74(19):6026-31.  https://doi.org/10.1128/AEM.00606-08  PMID: 18621872 
  39. Vieira PM, Mederle N, Lobo ML, Imre K, Mederle O, Xiao L, et al. Molecular characterisation of Cryptosporidium (Apicomplexa) in children and cattle in Romania. Folia Parasitol (Praha). 2015;62:2015.002. PMID: 25960546
  40. Elwin K, Chalmers RM, Hadfield SJ, Hughes S, Hesketh LM, Rothburn MM, et al. Serological responses to Cryptosporidium in human populations living in areas reporting high and low incidences of symptomatic cryptosporidiosis. Clin Microbiol Infect. 2007;13(12):1179-85.  https://doi.org/10.1111/j.1469-0691.2007.01823.x  PMID: 17850343 
  41. Okhuysen PC, Chappell CL, Sterling CR, Jakubowski W, DuPont HL. Susceptibility and serologic response of healthy adults to reinfection with Cryptosporidium parvum. Infect Immun. 1998;66(2):441-3.  https://doi.org/10.1128/IAI.66.2.441-443.1998  PMID: 9453592 
  42. World Health Organization (WHO). Water safety plan: A field guide to improving drinking-water safety in small communities. Geneva: WHO; 2014. Available from: https://www.euro.who.int/__data/assets/pdf_file/0004/243787/Water-safety-plan-Eng.pdf
  43. European Union (EU). Directive 2020/2184 of the European Parliament and of the Council of 16 December 2020 on the quality of water intended for human consumption (recast). Office of the European Union. 23.12.2020: L435/1. Available from: https://eur-lex.europa.eu/eli/dir/2020/2184/oj

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