Does each bead count? A reduced-cost approach for recovering waterborne protozoa from challenge water using immunomagnetic separation

Natália de Melo Nasser Fava, Kamila Jessie Sammarro Silva, William J Snelling, Nigel G Ternan, JSG Dooley, Lyda P Sabogal-Paz

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4 Citations (Scopus)
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Giardia duodenalis and Cryptosporidium spp. are two of the most prominent aetiological agents of waterborne diseases. Therefore, efficient and affordable methodologies for identifying and quantifying these parasites in water are increasingly necessary. USEPA Method 1623.1 is a widely used and validated protocol for detecting these parasites in water samples. It consists of a concentration step, followed by parasite purification and visualization by immunofluorescence microscopy. Although efficient, this method has a high cost particularly due to the immunomagnetic separation (IMS) step, which is most needed with complex and highly contaminated samples. Based on this, the present study aimed to determine whether it is possible to maintain the efficiency of Method 1623.1 while reducing the amount of beads per reaction, using as a matrix the challenge water recommended by the World Health Organization. As for Giardia cysts, a satisfactory recovery efficiency (RE) was obtained using 50% less IMS beads. This was evaluated both with a commercial cyst suspension (56.1% recovery) and an analytical quality assessment (47.5% recovery). Although RE rates obtained for Cryptosporidium parvum did not meet Method 1623.1 criteria in any of the experimental conditions tested, results presented in this paper indicated the relevance of the described adaptations, even in challenge water.

Original languageEnglish
Article numberjwh2021005
Pages (from-to)436-447
Number of pages12
JournalJournal of Water and Health
Issue number3
Early online date31 Mar 2021
Publication statusPublished (in print/issue) - 1 Jun 2021

Bibliographical note

Funding Information:
This work was supported by the Global Challenges Research Fund (GCRF) UK Research and Innovation (SAFEWATER; EPSRC Grant Reference EP/P032427/1). The authors would also like to thank the Coordination for the Improvement of Higher Education Personnel (CAPES-PROEX – Brazil, Financial code 001) for the PhD scholarship awarded to Kamila Jessie Sammarro Silva.

Publisher Copyright:
© 2021 IWA Publishing. All rights reserved.


  • Cryptosporidium spp. oocysts
  • Giardia spp. cysts
  • low-cost recovery methods
  • parasitic protozoa
  • recovery efficiency
  • Recovery efficiency
  • Low-cost recovery methods
  • Parasitic protozoa


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