Comparison of in vitro viability methods for Cryptosporidium oocysts

• Published in: Experimental parasitology Vol. 187; pp. 30 - 36
• Main Authors: Vande Burgt, Nathan H., Auer, Agathe, Zintl, Annetta
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-04-2018
• Subjects: Azides; Cell Adhesion; Cryptosporidium - genetics; Cryptosporidium - physiology; Excystation; Fluorescence in-situ hybridization; Fluorescent Dyes; In Situ Hybridization, Fluorescence; Indoles; Oocysts - physiology; PMA-qPCR; Polymer adhesion; Polymers; Propidium - analogs & derivatives; Propidium iodide; Real-Time Polymerase Chain Reaction; RNA, Protozoan - analysis; PMA-qPCR; Polymer adhesion; Fluorescence in-situ hybridization; PMA; FISH; Excystation; Propidium iodide; PBS-Tween; PI; HEX; HBSS; DIC
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2018.03.002

The water-borne protozoan parasite Cryptosporidium parvum forms oocysts that can persist for long periods of time in the environment, even though the sporozoites inside the oocysts may no longer be viable, making it difficult to assess the associated risk of infection. In this study, we compared the ability of various in vitro methods to discriminate viable from non-viable oocysts, including excystation, DAPI/PI staining, RNA FISH, PMA-qPCR and a novel polymer slide adhesion method. With the notable exception of our in vitro excystation protocol, all methods were found to be useful for identifying viable oocysts.
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•Excystation does not accurately assess the viability of Cryptosporidium oocysts.•DAPI/PI staining, RNA FISH, and PMA-qPCR discriminate viable and non-viable oocysts.•Live oocysts adhere preferentially to the polymer coated Nexterion Slide P.