1. Craun GF, Brunkard JM, Yoder JS, Roberts VA, Carpenter J, Wade T, Calderon RL, Roberts JM, Beach MJ, Roy SL. Causes of outbreaks associated with drinking water in the United States from 1971 to 2006. Clin Microbiol Rev. 2010:23(3):507–528. Google Scholar

2. Karanis P, Kourenti C, Smith H. Waterborne transmission of protozoan parasites: a worldwide review of outbreaks and lessons learnt. J Water Health. 2007;5(1):1–38. Google Scholar

3. Gill EE, Fast NM. Assessing the microsporidia-fungi relationship: combined phylogenetic analysis of eight genes. Gene. 2006;375:103–109. Google Scholar

4. Coffey CM, Collier SA, Gleason MS, Yoder JS, Kirk MD, Richardson AM, Fullerton KE, Benedict KM. Evolving epidemiology of reported giardiasis cases in the United States, 1995-2016. Clin Infect Dis. 2021;72(5):764–770. Google Scholar

5. Conners EE, Miller AD, Balachandran N, Robinson BM, Benedict KM. Giardiasis outbreaks - United States, 2012-2017. Morb Mortal Wkly Rep. 2021;70(9):304–307. Google Scholar

6. Ford TE. Microbiological safety of drinking water: United States and global perspectives. Environ Health Perspect. 1999;107(Suppl 1):191–206. Google Scholar

7. Furness BW, Beach MJ, Roberts JM. Giardiasis surveillance—United States, 1992–1997. MMWR CDC Surveill Summ. 2000;49(7):1–13. Google Scholar

8. MacKenzie WR, Hoxie NJ, Proctor ME, Gradus MS, Blair KA, Peterson DE, Kazmierczak JJ, Addiss DG, Fox KR, Rose JB, et al. A massive outbreak in Milwaukee of Cryptosporidium infection transmitted through the public water supply. New Engl J Med. 1994;331(3):161–167. Google Scholar

9. Ungar BLP. Cryptosporidium and cryptosporidiosis. In: Broder S, Merigan Jr TC, Bolognesi D, eds. Textbook of AIDS Medicine. Baltimore (MD): Williams & Wilkins; 1994. Google Scholar

10. Anderson VR, Curran MP. Nitazoxanide: a review of its use in the treatment of gastrointestinal infection. Drugs. 2007;67(13):1947–1967. Google Scholar

11. Chen XM, Keithly JS, Paya CV, LaRusso NF. Cryptosporidiosis. New Engl J Med. 2002;346(22):1723–1731. Google Scholar

12. Waterborne Disease & Outbreak Surveillance Reporting: Cryptosporidiosis NNDSS Summary Report for 2019. Atlanta (GA): CDC Division of Health Informatics and Surveillance, Centers for Disease Control and Prevention [published 2019; accessed 7 Nov 2021]. https://www.cdc.gov/healthywater/surveillance/cryptosporidium/cryptosporidium-2019.html Google Scholar

13. Leoni F, Amar C, Nichols G, Pedraza-Diaz S, Mclauchlin J. Genetic analysis of Cryptosporidium from 2414 humans with diarrhoea in England between 1985 and 2000. J Med Microbiol. 2006;55(Pt 6):703–707. Google Scholar

14. Chalmers RM, Elwin K, Thomas AL, Guy EC, Mason B. Long-term Cryptosporidium typing reveals the aetiology and species-specific epidemiology of human cryptosporidiosis in England and Wales, 2000 to 2003. Euro Surveill. 2009;14(2):19086. Google Scholar

15. Fayer R, Trout JM, Xiao L, Morgan UM, Lal AA, Dubey JP. Cryptosporidium canis n. sp. from domestic dogs. J Parasitol. 2001;87(6):1415–1422. Google Scholar

16. Gatei W, Ashford RW, Beeching NJ, Kamwati SK, Greensill J, Hart CA. Cryptosporidium muris infection in an HIV-infected adult, Kenya. Emerg Infect Dis. 2002;8(2):204–206. Google Scholar

17. Morgan U, Weber R, Xiao L, Sulaiman I, Thompson RC, Ndiritu W, Lal A, Moore A, Deplazes P. Molecular characterization of Cryptosporidium isolates obtained from human immunodeficiency virus-infected individuals living in Switzerland, Kenya, and the United States. J Clin Microbiol. 2000;38(3):1180–1183. Google Scholar

18. Pedraza-Diaz S, Amar C, Iversen AM, Stanley PJ, Mclauchlin J. Unusual Cryptosporidium species recovered from human faeces: first description of Cryptosporidium felis and Cryptosporidium ‘dog type’ from patients in England. J Med Microbiol. 2001;50(3):293–296. Google Scholar

19. Pieniazek NJ, Bornay-Llinares FJ, Slemenda SB, da Silva AJ, Moura IN, Arrowood MJ, Ditrich O, Addiss DG. 1999. New Cryptosporidium genotypes in HIV-infected persons. Emerg Infect Dis. 5(3):444–449. Google Scholar

20. Xiao L, Bern C, Limor J, Sulaiman I, Roberts J, Checkley W, Cabrera L, Gilman RH, Lal AA. Identification of 5 types of Cryptosporidium parasites in children in Lima, Peru. J Infect Dis. 2001;183(3):492–497. Google Scholar

21. Zahedi A, Monis P, D. Deere D, Ryan U. 2021. Wastewater-based epidemiology-surveillance and early detection of waterborne pathogens with a focus on SARS-CoV-2, Cryptosporidium and Giardia. Parasitol Res. Jan 6:1-22. https://doi.org/10.1007/s00436-020-07023-5 Google Scholar

22. Zahedi A, Ryan U. Cryptosporidium - An update with an emphasis on foodborne and waterborne transmission. Res Vet Sci. 2020;132:500–512. Google Scholar

23. Messner MJ, Wolpert RL. Cryptosporidium and Giardia occurrence in ICR drinking water sources: Statistical analysis of ICR data. In: McGuire MJ, McLain JL, Obolensky A, eds. Information Collection Rule Data Analysis. Denver (CO): AWWA Research Foundation and the American Water Works Association; 2003, p. 463. Google Scholar

24. McLauchlin J, Amar C, Pedraza-Díaz S, Nichols GL. Molecular epidemiological analysis of Cryptosporidium spp. in the United Kingdom: results of genotyping Cryptosporidium spp. in 1,705 fecal samples from humans and 105 fecal samples from livestock animals. J Clin Microbiol. 2000;38(11):3984–3990. Google Scholar

25. Sulaiman IM, Xiao L, Yang C, Escalante L, Moore A, Beard CB, Arrowood MJ, Lal AA. 1998. Differentiating human from animal isolates of Cryptosporidium parvum. Emerg Infect Dis. 1998;4(4) :681–685. Google Scholar

26. Xiao L, Ryan UM. Molecular epidemiology. In: Fayer R, Xiao L, eds. Cryptosporidium and Cryptosporidiosis. Boca Raton, Fla: CRC Press; 2008, p. 119. Google Scholar

27. Robinson G, Wright S, Elwin K, Hadfield SJ, Katzer F, Bartley PM, Hunter PR, Nath M, Innes EA, Chalmers RM. Re-description of Cryptosporidium cuniculus Inman and Takeuchi, 1979 (Apicomplexa: Cryptosporidiidae): morphology, biology and phylogeny. Int J Parasitol. 2010;40(13):1539–1548. Google Scholar

28. Chalmers RM, Robinson G, Elwin K, Hadfield SJ, Xiao L, Ryan U, Modha D, Mallaghan C. Cryptosporidium rabbit genotype, a newly identified human pathogen. Emerg Infect Dis. 2009;15(5):829–830. Google Scholar

29. U.S. Environmental Protection Agency. 2006. Long Term 2 Enhanced Surface Water Treatment Rule; Final Rule. Fed Reg. 71:3653. Google Scholar

30. Benenson MW, Takafuji ET, Lemon SM, Greenup RL, Sulzer AJ. Oocyst-transmitted toxoplasmosis associated with ingestion of contaminated water. New Engl J Med. 1982;307(11):666–669. Google Scholar

31. Bowie WR, King AS, Werker DH, Isaac-Renton JL, Bell A, Eng SB, Marion SA. Outbreak of toxoplasmosis associated with municipal drinking water. The BC Toxoplasma Investigation Team. Lancet. 1997;350(9072):173–177. Google Scholar

32. Vaudaux JD, Muccioli C, James ER, Silveira C, Magargal SL, Jung C, Dubey JP, Jones JL, Doymaz MZ, Bruckner DA, et al. Identification of an atypical strain of Toxoplasma gondii as the cause of a waterborne outbreak of toxoplasmosis in Santa Isabel do Ivai, Brazil. J Infect Dis. 2010;202(8):1226–1233. Google Scholar

33. Dubey JP. Toxoplasmosis. J Amer Vet Med Assoc. 1994;205(11):1593–1598. Google Scholar

34. Isaac-Renton J, Bowie WR, King A, Irwin GS, Ong CS, Fung CP, Shokeir MO, Dubey JP. Detection of Toxoplasma gondii oocysts in drinking water. Appl Environ Microbiol. 1998;64(6):2278–2280. Google Scholar

35. Sroka J, Wójcik-Fatla A, Dutkiewicz J. Occurrence of Toxoplasma gondii in water from wells located on farms. Ann Agric Environ Med. 2006;13(1):169–175 Google Scholar

36. Dowd SE, John D, Eliopolus J, Gerba CP, Naranjo J, Klein R, López B, de Mejía M, Mendoza CE, Pepper IL. Confirmed detection of Cyclospora cayetanensis, Encephalitozoon intestinalis and Cryptosporidium parvum in water used for drinking. J Wat Health. 2003;1(3):117–123. Google Scholar

37. Craun G, Calderon RL, Nwachuku N. Causes of waterborne outbreaks reported in the United States, 1991–1998. In: Hunter PR, Waite M, Ronchi E, eds. Drinking water and infectious disease: Establishing the links. Boca Raton (FL): CRC Press; 2003, p. 105. Google Scholar

38. Ortega YR, & R. Sanchez R. Update on Cyclospora cayetanensis: a food-borne and waterborne parasite. Clin Microbiol Rev. 2010;23(1):218–234. Google Scholar

39. Ackers JP, Mirelman D. Progress in research on Entamoeba histolytica pathogenesis. Curr Opin Microbiol. 2006;9(4):367–373. Google Scholar

40. Vavra J, Larson JIR. Structure of the microsporidia. In: Wittner M, ed. The Microsporidia and Microsporidiosis, Washington DC: American Society of Microbiology; 1999, p. 7. Google Scholar

41. Visvesvara GS, Moura H, Leitch GJ, Schwartz DA. Culture and propagation of microsporidia. In: Wittner M, ed. The Microsporidia and Microsporidiosis. Washington DC: American Society of Microbiology; 1999, p. 363. Google Scholar

42. Cotte L, Rabodonirina M, Chapuis F, Bailly F, Bissuel F, Raynal C, Gelas P, Persat F, Piens MA, Trepo C. Waterborne outbreak of intestinal microsporidiosis in persons with and without human immunodeficiency virus infection. J Infect Dis. 1999;180(6):2003–2008. Google Scholar

43. Thurston-Enriquez JA, Watt P, Dowd SE, Enriquez R, Pepper IL, Gerba CP. Detection of protozoan parasites and microsporidia in irrigation waters used for crop production. J Food Protect. 2002;65(2):378–382. Google Scholar

44. Nagington J, Watson PG, Playfair TJ, Mcgill J, Jones BR, Steele AD. Amebic infection of the eye. Lancet. 1974;304(7896):1537–1540. Google Scholar

45. Jones DB, Visvesvara GS, Robinson NM. Acanthamoeba polyphaga keratitis and Acanthamoeba uveitis associated with fatal meningoencephalitis. Trans Ophthalmol Soc UK. 1975;95(2):221–232. Google Scholar

46. De Jonckheere JF. Ecology of Acanthamoeba. Rev Infect Dis. 1991;13(Suppl 5):S385–S387. Google Scholar

47. Mergeryan H. The prevalence of Acanthamoeba in the human environment. Rev Infect Dis. 1991;13(Suppl 5):S390–S391. Google Scholar

48. Rohr U, Weber S, Michel R, Selenka F, Wilhelm W. Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance. Appl Environ Microbiol. 1998;64(5):1822–1824. Google Scholar

49. Szénási Z, Endo T, Yagita K, Nagy E. Isolation, identification and increasing importance of ‘free-living’ amoebae causing human disease. J Med Microbiol. 1998;47(1):5–16. Google Scholar

50. Illingworth CD, Cook SD. Acanthamoeba keratitis. Surv Opthalmol. 1998;42(6):493–508. Google Scholar

51. U.S. Environmental Protection Agency. 2003. Announcement of regulatory determinations for priority contaminants on the drinking water Contaminant Candidate List. Fed Reg. 68:42897. Google Scholar

52. Gharpure R, Bliton J, Goodman A, Ali IKM, Yoder J, Cope JR. Epidemiology and clinical characteristics of primary amebic meningoencephalitis caused by Naegleria fowleri: A global review. Clin Infect Dis. 2020;73:e19–e27. Google Scholar

53. Centers for Disease Control and Prevention. How common are Naegleria fowleri infections in the United States? [reviewed 14 Oct 2021; accessed 7 Nov 2021] https://www.cdc.gov/parasites/naegleria/general.html. Google Scholar

54. Blair B, Sarkar P, Bright KR, Marciano-Cabral F, Gerba CP. Naegleria fowleri in well water. Emerg Infect Dis. 2008;14(9):1499–1501. Google Scholar

55. Marciano-Cabral F, Maclean R, Mensah A, LaPat-Polasko L. Identification of Naegleria fowleri in domestic water sources by nested PCR. Appl Environ Microbiol. 2003;69(10):5864–5869. Google Scholar

56. Marciano-Cabral F, Puffenbarger R, Cabral GA. The increasing importance of Acanthamoeba infections. J Eukaryot Microbiol. 2000;47(1):29–36. Google Scholar

57. Cirillo JD, Falkow S, Tompkins LS, Bermudez LE. Interaction of Mycobacterium avium with environmental amoebae enhances virulence. Infect Immun. 1997;65(9):3759–3567. Google Scholar

58. Fritsche TR, Horn M, Wagner M, Herwig RP, Schleifer KH, Gautom RK. Phylogenetic diversity among geographically dispersed Chlamydiales endosymbionts recovered from clinical and environmental isolates of Acanthamoeba spp. Appl Environ Microbiol. 2000;66(6):2613–2619. Google Scholar

59. Rochelle PA. Detection of protozoa in environmental water samples. In: Rochelle PA, ed. Environmental molecular microbiology: Protocols and applications. Wymondham, UK: Horizon Scientific Press; 2001, p. 91. Google Scholar

60. Kuhn RC, Oshima KH. Hollow-fiber ultrafiltration of Cryptosporidium parvum oocysts from a wide variety of 10–L surface water samples. Can J Microbiol. 2002:48(6):542–549. Google Scholar

61. Hill VR, Kahler AM, Jothikumar N, Johnson TB, Hahn D, Cromeans TL. Multistate evaluation of an ultrafiltration-based procedure for simultaneous recovery of enteric microbes in 100-liter tap water samples. Appl Environ Microbiol. 2007;73(13):4218–4225. Google Scholar

62. Dowd SE, Gerba CP, Pepper IL. Confirmation of the human-pathogenic microsporidia Enterocytozoon bieneusi, Encephalitozoon intestinalis, and Vittaforma corneae in water. Appl Environ Microbiol. 1998;64(9):3332–3335. Google Scholar

63. Sturbaum GD, Ortega YR, Gilman RH, Sterling CR, Cabrera L, Klein DA. Detection of Cyclospora cayetanensis in wastewater. Appl Environ Microbiol. 1998;64(6):2284–2286. Google Scholar

64. Sparfel JM, Sarfati C, Liguory O, Caroff B, Dumoutier N, Gueglio B, Billaud E, Raffi F, Molina JM, Miegeville M, et al. Detection of microsporidia and identification of Enterocytozoon beieneusi in surface water by filtration followed by specific PCR. J Eukaryot Microbiol. 1997;44(6):78S. Google Scholar

65. Hoffman RM, Wolk DM, Spencer SK, Borchardt MA. Development of a method for the detection of waterborne microsporidia. J Microbiol Methods. 2007;70(2):312–318. Google Scholar

66. Johnson AM, Hanley K, Rochelle PA, De Leon R. Development of an assay for detecting microsporidia in water. In: Proceedings of the AWWA Water Quality Technology Conference, M6: Detection of Emerging Pathogens, 2; 2002 Nov. 10–14; Seattle (WA). Denver (CO): American Water Works Association, 2002. Google Scholar

67. Durigan M, Murphy HR, da Silva AJ. Dead-end ultrafiltration and DNA-based methods for detection of Cyclospora cayetanensis in agricultural water. Appl Environ Microbiol. 2020;86(23):e01595-20. Google Scholar

68. Kahler AM, Mattioli MC, da Silva AJ, Hill V. Detection of Cyclospora cayetanensis in produce irrigation and wash water using large-volume sampling techniques. Food Waterborne Parasitol. 2021;22:e00110. Google Scholar

69. Villena I, Aubert D, Gomis P, Ferté H, Inglard JC, Denis-Bisiaux H, Dondon J-M, Pisano E, Ortis N, Pinon J-M. Evaluation of a strategy for Toxoplasma gondii oocyst detection in water. Appl Environ Microbiol. 2004;70(7):4035–4039. Google Scholar

70. Dumetre A, Darde ML. Immunomagnetic separation of Toxoplasma gondii oocysts using a monoclonal antibody directed against the oocyst wall. J Microbiol Methods. 2005;61(2):209–217. Google Scholar

71. Zuckerman U, Tzipori S. Portable continuous flow centrifuge and method 1623 for monitoring of waterborne protozoa from large volumes of various water matrices. J Appl Microbiol. 2006;100(6):1220–1227. Google Scholar

72. Method 1622: Cryptosporidium in Water by Filtration/IMS/FA; EPA 815-R-05-001. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2005. Google Scholar

73. Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA; EPA 815-R-05-002. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2005. Google Scholar

74. Method 1623.1: Cryptosporidium and Giardia in water by filtration/IMS/FA; EPA 815-R-12-001. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2012. Google Scholar

1. Hill VR, Kahler AM, Jothikumar N, Johnson TB, Hahn D, Cromeans TL. Multistate evaluation of an ultrafiltration-based procedure for simultaneous recovery of enteric microbes in 100-liter tap water samples. Appl Environ Microbiol. 2007;73(13):4218–4225. Google Scholar

2. Morales-Morales HA, Vidal G, Olszewski J, Rock CM, Dasgupta D, Oshima KH, Smith GB. Optimization of a reusable hollow fiber ultrafilter for simultaneous concentration of enteric bacteria, protozoa, and viruses from water. Appl Environ Microbiol. 2003;69(7):4098–4102. Google Scholar

3. Lindquist HD, Harris S, Lucas S, Hartzel M, Riner D, Rochele P, Deleon R. Using ultrafiltration to concentrate and detect Bacillus anthracis, Bacillus atrophaeus subspecies globigii, and Cryptosporidium parvum in 100-liter water samples. J Microbiol Methods. 2007;70(3):484–492. Google Scholar

4. Francy DS, Bushon RN, Kephart CM, Brady AM, Bertke EE, Stetlzer E, Schaffer FW, Lindquist H. Comparison of traditional and molecular analytical methods for detecting biological agents in drinking water using ultrafiltration techniques. J Microbiol Meth. 2009;107:1479–1491. Google Scholar

5. Rhodes ER, Villegas LF, Shaw NJ, Miller C, Villegas EN. A modified EPA Method 1623 that uses tangential flow hollow-fiber ultrafiltration and heat dissociation steps to detect waterborne Cryptosporidium and Giardia spp. J Vis Exp. 2012;(65):4177. https://doi.org/10.3791/4177. Google Scholar

6. Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA; EPA 815-R-05-002. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2005. Google Scholar

7. Method 1623.1: Cryptosporidium and Giardia in Water by Filtration/IMS/FA; EPA 816-R-12-001. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2012. Google Scholar

8. Francy DS, Simmons III OD, Ware MW, Granger EJ, Sobsey MD, Schaefer III FW. Effects of seeding procedures and water quality on recovery of Cryptosporidium oocysts from stream water by using U.S. Environmental Protection Agency Method 1623. Appl Environ Microbiol. 2004;70(7):4118–4128. Google Scholar

9. McCuin RM, Clancy JL. Modifications to United States Environmental Protection Agency Methods 1622 and 1623 for detection of Cryptosporidium oocysts and Giardia cysts in water. Appl Environ Microbiol. 2003;69(1):267–274. Google Scholar

10. Robertson LJ, Gjerde B. Effect of sample holding time on recovery of Cryptosporidium oocysts and Giardia cysts from water samples. Appl Environ Microbiol. 2000;66(4):1724–1725. Google Scholar

11. Kuhn RC, Rock CM, Oshima KH. Effects of pH and magnetic material on immunomagnetic separation of Cryptosporidium oocysts from concentrated water samples. Appl Environ Microbiol. 2002;68(4):2066–2070. Google Scholar

12. Ware MW, Wymer L, Lindquist HD, Schaffer III FW. Evaluation of an alternative IMS dissociation procedure for use with Method 1622: detection of Cryptosporidium in water. J Microbiol Methods. 2003;55(3):575–583. Google Scholar

13. Training for Drinking Water Laboratory Certification. U.S. Environmental Protection Agency [accessed 09 November 2021]. https://www.epa.gov/dwlabcert/training-drinking-water-laboratory-certification#crypto-training Google Scholar

14. Overview of US EPA Giardia and Cryptosporidium detection methods. U.S. Environmental Protection Agency [published 27 March 2014; accessed 09 November 2021]. https://www.youtube.com/watch?v=akXNxM94qkU Google Scholar

15. U.S. Environmental Protection Agency. 2013. Laboratory Quality Assurance Evaluation Program for the Analysis of Cryptosporidium under the Safe Drinking Water Act. Fed Reg. 78(172):54643. Google Scholar

16. Supplement 2 to the Fifth Edition of the Manual for the Certification of Laboratories Analyzing Drinking Water; EPA 815-F-12-006. Washington DC: Office of Water, U.S. Environmental Protection Agency; 2012. Google Scholar

17. Long term 2 enhanced surface water treatment rule documents: LT2 Cryptosporidium and E. coli sample collection recommendations pocket guide. U.S. Environmental Protection Agency [published April 2006; accessed 09 November 2021]. https://www.epa.gov/dwreginfo/long-term-2-enhanced-surface-water-treatment-rule-documents#lt2cryptosample Google Scholar

18. Cryptosporidium analysis: using a dispersant. U.S. Environmental Protection Agency. [published 09 August 2012; accessed 09 November 2021]. https://www.youtube.com/watch?v=U-pBHvBeazs Google Scholar

19. Drinking Water Inspectorate. Standard operating protocol for the monitoring of Cryptosporidium oocysts in treated water supplies to satisfy the water supply (water quality) regulations, U.K. London: Department of Environment; 2005. Google Scholar

20. Leetz AS, Sotiriadou I, Ongerth J, Karanis P. An evaluation of primers amplifying DNA targets for the detection of Cryptosporidium spp. using C. parvum HNJ-1 Japanese isolate in water. Parasitol Res. 2007;101(4):951–962. Google Scholar

21. Rochelle PA. Detection of protozoa in environmental water samples. In: Rochelle PA, ed. Environmental molecular microbiology: Protocols and applications. Wymondham (UK): Horizon Scientific Press; 2001, p. 91. Google Scholar

22. Xiao L, Alderisio K, Singh A. Development and standardization of a Cryptosporidium genotyping tool for water samples. Denver (CO): AWWA Research Foundation; 2006. Google Scholar

23. Guy RA, Payment P, Krull UJ, Horgen PA. Real-time PCR for quantification of Giardia and Cryptosporidium in environmental water samples and sewage. Appl Environ Microbiol. 2003;69(9):5178–5185. Google Scholar

24. Zahedi A, Gofton AW, Greay T, Monis P, Oskam C, Ball A, Bath A, Watkinson A, Robertson I, Ryan U. Profiling the diversity of Cryptosporidium species and genotypes in wastewater treatment plants in Australia using next generation sequencing. Sci Total Environ. 2018;644:635–648. Google Scholar

25. McLauchlin J, Amar C, Pedraza-Díaz S, Nichols GL. Molecular epidemiological analysis of Cryptosporidium spp. in the United Kingdom: results of genotyping Cryptosporidium spp. in 1,705 fecal samples from humans and 105 fecal samples from livestock animals. J Clin Microbiol. 2000;38(11):3984–3990. Google Scholar

26. Sulaiman IM, Xiao L, Yang C, Escalante L, Moore A, Beard CB, Arrowood MJ, Lal AA. Differentiating human from animal isolates of Cryptosporidium parvum. Emerg Infect Dis. 1998;4(4):681–685. Google Scholar

27. Xiao L, Alderisio K, Limor J, Royer M, Lal AA. Identification of species and sources of Cryptosporidium oocysts in storm waters with a small-subunit rRNA-based diagnostic and genotyping tool. Appl Environ Microbiol. 2000;66(12):5492–5498. Google Scholar

28. Xiao L, A. Singh A, Limor J, Graczyk TK, Gradus S, Lal AA. Molecular characterization of Cryptosporidium oocysts in samples of raw surface water and wastewater. Appl Environ Microbiol. 2001;67(3):1097–1101. Google Scholar

29. Monis PT, Andrews RH, Mayrhofer G, Ey PL. Genetic diversity within the morphological species Giardia intestinalis and its relationship to host origin. Infect Genet Evol. 2003;3(1):29–38. Google Scholar

30. Cacciò SM, Thompson RC, McLauchlin J, Smith HV. Unravelling Cryptosporidium and Giardia epidemiology. Trends Parasitol. 2005;21(9):430–437. Google Scholar

31. Lasek-Nesselquist E, Welch DM, Sogin ML. The identification of a new Giardia duodenalis assemblage in marine vertebrates and a preliminary analysis of G. duodenalis population biology in marine systems. Int J Parasitol. 2010;40(9):1063–1074. Google Scholar

32. Wallis PM, Erlandsen SL, Isaac-Renton JL, Olson ME, Robertson WJ, Van Keulen H. Prevalence of Giardia cysts and Cryptosporidium oocysts and characterization of Giardia spp. isolated from drinking water in Canada. Appl Environ Microbiol. 1996;62(8):2789–2797. Google Scholar

33. Qvarnstrom Y, James C, Xayavong M, Holloway BP, Visvesvara GS, Sriram R, da Silva AJ. Comparison of real-time PCR protocols for differential laboratory diagnosis of amebiasis. J Clin Microbiology. 2020;43(11):5491-5497. Google Scholar

34. Howe DK, Vodkin MH, Novak RJ, Visvesvara G, McLaughlin GL. Identification of two genetic markers that distinguish pathogenic and nonpathogenic strains of Acanthamoeba spp. Parasitol Res. 1997;83(4):345–348. Google Scholar

35. Weiss LM, Vossbrinck CR. Microsporidosis: molecular and diagnostic aspects. Adv Parasitol. 1998;40:351–395. Google Scholar

36. Grigg ME, Boothroyd JC. Rapid identification of virulent type I strains of the protozoan pathogen Toxoplasma gondii by PCR-restriction fragment length polymorphism analysis at the B1 gene. J Clin Microbiol. 2001;39(1):398–400. Google Scholar

37. Nichols RAB, Connelly L, Sullivan CB, Smith HV. Identification of Cryptosporidium species and genotypes in Scottish raw and drinking waters during a one-year monitoring period. Appl Environ Microbiol. 2010;76(17):5977–5986. Google Scholar

38. Di Giovanni GD, Hoffman RM, Sturbaum GD. Development of a Cryptosporidium genotyping method for regulatory microscope slides. Project 4099. Denver (CO): Water Research Foundation; 2010. Google Scholar

39. Di Giovanni GD, Barrella KM, Hoffman RM, Sturbaum GD. Cryptosporidium Genotyping Workshop and Round Robin. Project 4284. Denver (CO): Water Research Foundation; 2014. Google Scholar

40. Chalmers RM, Ferguson C, Cacciò S, Gasser RB, Abs El-Osta YG, Heijnen L, Xiao L, Elwin K, Hadfield S, Sinclair M, et al. 2005. Direct comparison of selected methods for genetic categorisation of Cryptosporidium parvum and Cryptosporidium hominis species. Int J Parasitol. 35(4):397–410. Google Scholar

41. Ferguson C, Deere D, Sinclair M, Chalmers RM, Elwin K, Hadfield S, Xiao L, Ryan U, R. Gasser R, Abs El-Osta Y, et al. Meeting report: application of genotyping methods to assess risks from Cryptosporidium in watersheds. Environ Health Perspect. 2006;114(3):430–434. Google Scholar

42. Ruecker N, Neumann N, Rochelle P, Via S, Albert J. Developing a strategy to increase the value of regulatory Cryptosporidium monitoring. Denver (CO): Water Research Foundation; 2009. Google Scholar

43. Ruecker NJ, Bounsombath N, Wallis P, Ong CS, Isaac-Renton JL, Neumann NF. Molecular forensic profiling of Cryptosporidium species and genotypes in raw water. Appl Environ Microbiol. 2005;71(12):8991–8994. Google Scholar

44. Nichols RAB, Campbell BM, Smith HV. Molecular fingerprinting of Cryptosporidium oocysts isolated during water monitoring. Appl Environ Microbiol. 2006;72(8):5428–5435. Google Scholar

45. Schupp DG, Erlandsen SL. A new method to determine Giardia cyst viability: correlation of fluoerscein diacetate and propidium iodide staining with animal infectivity. Appl Environ Microbiol. 1987;53(4):704–707. Google Scholar

46. Smith AL, Smith HV. A comparison of fluorescein diacetate and propidium iodide staining and in vitro excystation for determining Giardia intestinalis cyst viability. Parasitol. 1989;99(Pt 3):329–331. Google Scholar

47. Smith HV. Detection of Cryptosporidium and Giardia in water. In: Pickup RW, Saunders JR, eds. Molecular Approaches to Environmental Microbiology. Hemel Hempstead (UK): Ellis-Horwood Ltd.; 1996, p. 195. Google Scholar

48. Campbell AT, Robertson LJ, Smith HV. Viability of Cryptosporidium parvum oocysts: correlation of in vitro excystation with inclusion or exclusion of fluorogenic vital dyes. Appl Environ Microbiol. 1992;58(11):3488–3493. Google Scholar

49. Bukhari Z, Marshall MM, Korich DG, Fricker CR, Smith HV, Rosen J, Clancy JL. Comparison of Cryptosporidium parvum viability and infectivity assays following ozone treatment of oocysts. Appl Environ Microbiol. 2000;66(7):2972–2980. Google Scholar

50. Hallier-Soulier S, Guillot E. An immunomagnetic separation-reverse transcription polymerase chain reaction (IMS-RT-PCR) test for sensitive and rapid detection of viable waterborne Cryptosporidium parvum. Environ Microbiol. 2003;5(7):592–598. Google Scholar

51. Maux M, Bertrand I, Gantzer C, Schwartzbrod J. Estimating Giardia cyst viability using RT-PCR. Water Supply. 2002;2(3):107–115. Google Scholar

52. Widmer G, Orbacz EA, Tzipori S. β-tubulin mRNA as a marker of Cryptosporidium parvum oocyst viability. Appl Environ Microbiol. 1999;65(4):1584–1588. Google Scholar

53. Brescia CC, Griffin SM, Ware MW, Varughese EA, Egorov AI, Villegas EN. Cryptosporidium propidium monoazide-PCR, a molecular biology-based technique for genotyping of viable Cryptosporidium oocysts. Appl Environ Microbiol. 2009;75(21):6856–6863. Google Scholar

54. Peng MM, Xiao L, Freeman AR, Arrowood MJ, Escalante AA, Weltman AC, Ong CSL, Mackenzie WR, Lal AA, Beard CB. Genetic polymorphism among Cryptosporidium parvum isolates: Evidence of two distinct human transmission cycles. Emerg Infect Dis. 1997;3(4):567–573. Google Scholar

55. Rochelle PA, Marshall MM, Mead JR, Johnson AM, Korich DG, Rosen JS, De Leon R. Comparison of in vitro cell culture and a mouse assay for measuring infectivity of Cryptosporidium parvum. Appl Environ Microbiol. 2002;68(8):3809–3817. Google Scholar

56. Widmer G, Akiyoshi D, Buckholt MA, Feng X, Rich SM, Deary KM, Bowman CA, Xu P, Wang Y, Wang X, et al. Animal propagation and genomic survey of a genotype 1 isolate of Cryptosporidium parvum. Mol Biochem Parasitol. 2000;108(2):187–197. Google Scholar

57. Johnson AM, Linden K, Ciociola KM, De Leon R, Widmer G, Rochelle PA. UV inactivation of Cryptosporidium hominis as measured in cell culture. Appl Environ Microbiol. 2005;71(5):2800–2802. Google Scholar

58. Lalancette C, Di Giovanni GD, Prévost M. Improved risk analysis by dual direct detection of total and infectious Cryptosporidium oocysts on cell culture in combination with immunofluorescence assay. Appl Environ Microbiol. 2010;76(2):566–577. Google Scholar

59. Alderisio KA, McDonald LA, Gabel KW, Archuleta J, Di Giovanni GD. Improved cell culture immunofluorescent assay for detection of infectious Cryptosporidium spp. in prefinished water. AWWA Water Sci. 2019;1(2):e1126. Google Scholar

1. McCuin RM, Clancy JL. Cryptosporidium in wastewater: Occurrence, removal, and inactivation. Alexandria (VA) and IWA Publishing (London): Water Environment Research Foundation; 2006. Google Scholar

2. McCuin RM, Clancy JL. Methods for the recovery, isolation and detection of Cryptosporidium oocysts in wastewaters. J Microbiol Methods. 2005;63(1):73–88. Google Scholar

3. Gennaccarro AL, Mclaughlin MR, Quintero-Betancourt W, Huffman DE, Rose JB. Infectious Cryptosporidium parvum oocysts in final reclaimed effluent. Appl Environ Microbiol. 2003;69(8):4983–4984. Google Scholar

4. Quintero-Betancourt W, Gennaccaro AL, Scott TM, Rose JB. Assessment of methods for detection of infectious Cryptosporidium oocysts and Giardia cysts in reclaimed effluents. Appl Environ Microbiol. 2003;69(9):5380–5388. Google Scholar

5. Other Clean Water Act Test Methods: Microbiological. U.S. Environmental Protection Agency [published 2014; accessed 10 November 2021]. https://www.epa.gov/cwa-methods/other-clean-water-act-test-methods-microbiological Google Scholar

6. Method 1693: Cryptosporidium and Giardia in Disinfected Wastewater by Concentration/IMS/IFA; EPA 821-R-14-013.Washington DC: Office of Water (MS-140), U. S. Environmental Protection Agency; 2014. Google Scholar

1. Rochelle PA, Fallar D, Marshall MM, Montelone BA, Upton SJ, Woods K. Irreversible UV inactivation of Cryptosporidium spp. despite the presence of UV repair genes. J Eukaryot Microbiol. 2004;51(5):553–562. Google Scholar

2. Johnson AM, Linden K, Ciociola KM, De Leon R, Widmer G, Rochele PA. UV inactivation of Cryptosporidium hominis as measured in cell culture. Appl Environ Microbiol. 2005;71(5):2800–2802. Google Scholar

3. Gennaccaro AE, McLaughlin MR, Quintero-Betancourt W, Huffman DE, Rose JB. Infectious Cryptosporidium parvum oocysts in final reclaimed effluent. Appl Environ Microbiol. 2003;69(8):4983–4984. Google Scholar

4. Keegan AR, Fanok S, Monis PT, Saint CP. Cell culture-Taqman PCR assay for evaluation of Cryptosporidium parvum disinfection. Appl Environ Microbiol. 2003;69(5):2505–2511. Google Scholar

5. Slifko TR, Huffman DE, Rose JB. A most-probable-number assay for enumeration of infectious Cryptosporidium parvum oocysts. Appl Environ Microbiol. 1999;65(9):3936–3941. Google Scholar

6. Di Giovanni GD, Hashemi FH, Shaw NJ, Abrams FA, LeChevallier MW, Abbaszadegan A. Detection of infectious Cryptosporidium parvum oocysts in surface and filter backwash water samples by immunomagnetic separation and integrated cell culture PCR. Appl Environ Microbiol. 1999;65(8):3427–3432. Google Scholar

7. Rochelle PA, Marshall MM, Mead JR, Johnson AM, Korich DG, Rosen JS, De Leon R. Comparison of in vitro cell culture and a mouse assay for measuring infectivity of Cryptosporidium parvum. Appl Environ Microbiol. 2002;68(8):3809–3817. Google Scholar

8. Aboytes R, Di Giovanni GD, Abrams FA, Rheinecker C, McElroy W, Shaw N, LeChevallier MW. Detection of infectious Cryptosporidium in filtered drinking water. J Amer Wat Works Assoc. 2004;96(9):88–98. Google Scholar

9. LeChevallier MW, Di Giovanni GD, Clancy JE, Bukhari Z, Bukhari S, Rosen JS, Sobrinho J, Frey MM. Comparison of Method 1623 and cell culture-PCR for detection of Cryptosporidium spp. in source waters. Appl Environ Microbiol. 2003;69(2):971–979. Google Scholar

10. Quintero-Betancourt W, Gennaccaro AE, Scott TM, Rose JB. Assessment of methods for detection of infectious Cryptosporidium oocysts and Giardia cysts in reclaimed effluents. Appl Environ Microbiol. 2003;69(9):5380–5388. Google Scholar

11. Johnson AM, Rochelle PA, Di Giovanni GD. The risk of cryptosporidiosis from drinking water. In: Proceedings of the AWWA Water Quality Technology Conference; 2008 Nov. 16–20, Cincinnati, Ohio. Cryptosporidium—Analytical Methods and Risk Analysis. Denver (CO): American Water Works Association; 2008. Google Scholar

12. Alderisio KA, McDonald LA, Gabel KW, Archuleta J, Di Giovanni GD. Improved cell culture immunofluorescent assay for detection of infectious Cryptosporidium spp. in prefinished water. AWWA Water Science. 2019;1(2):e1126. Google Scholar

13. Johnson AM, Rochelle PA, Di Giovanni GD. Detection of Infectious Cryptosporidium in Conventionally Treated Drinking Water. Denver (CO): Water Research Foundation; 2010. Google Scholar

14. Arrowood MJ. In vitro cultivation. In: R. Fayer R, Xiao L, eds. Cryptosporidium and Cryptosporidiosis 2nd. ed. Boca Raton (FL): CRC Press; 2008, p. 499. Google Scholar

15. Rochelle PA, De Leon R. A review of methods for assessing the infectivity of Cryptosporidium parvum using in vitro cell culture. In: Smith M and Thompson KC, eds. Cryptosporidium, The Analytical Challenge. Royal Society of Chemistry, Cambridge: 2001, p. 88. Google Scholar

16. Davis JM. Basic cell culture. Oxford University Press; 2002. (Practical Approach Series) Google Scholar

17. Helgason CD, Miller C. Basic cell culture protocols. Totowa (NJ): Humana Press; 2004. (Methods in Molecular Biology) Google Scholar

18. Johnson AM, Di Giovanni GD, Rochelle PA. Comparison of assays for sensitive and reproducible detection of cell culture-infectious Cryptosporidium parvum and Cryptosporidium hominis in drinking water. Appl Environ Microbiol. 2012;78(1):156–162. Google Scholar

19. King BJ, Keegan AR, Phillips R, Fanok S, Monis PT. Dissection of the hierarchy and synergism of the bile derived signal on Cryptosporidium parvum excystation and infectivity. Parasitology. 2012;139(12):1533–1546. Google Scholar

20. Di Giovanni GD, Betancourt WQ, Hernandez J, Assadian NW, Flores Margez JP, Lopez EJ. Investigation of potential zooanthroponotic transmission of cryptosporidiosis and giardiasis through agricultural use of reclaimed wastewater. Int J Environ Health Res. 2006;16(6):405–418. Google Scholar