Evaluation of three flocculation methods for the purification of Cryptosporidium parvum oocysts from water samples

Authors


PD Dr P. Karanis, Institute for Medical Parasitology, Medical Faculty, University of Bonn, Sigmund-Freud Strasse 25, 53127 Bonn, Germany (e-mail: Panagiotis.Karanis@medizin.uni-koeln.de).

Abstract

Aims: Evaluation of three flocculation methods for the purification of Cryptosporidium parvum oocysts from tap water.

Methods and Results: Ferric sulphate, aluminium sulphate and calcium carbonate were compared for their recovery efficiency of C. parvum oocysts from tap water. Lower mean recovery was achieved by calcium carbonate (38·8%) compared with ferric sulphate (61·5%) and aluminium sulphate (58·1%) for the recovery of 2·5 × 105 oocysts l−1; 2·5 oocysts l−1 and 1 oocyst l−1 were adequately purified using ferric sulphate flocculation. In vitro excystation experiments showed that ferric sulphate flocculation does not markedly reduce the viability of oocysts.

Conclusions: Ferric sulphate flocculation is a simple and effective tool for the purification of C. parvum oocysts from tap water.

Significance and Impact of the Study: The high recovery rates and low impact on oocyst viability provided by ferric sulphate flocculation might be useful for the detection of Cryptosporidium oocysts in environmental water samples.

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