Environmental methods for Cryptosporidium

Abstract

A number of approaches offer promise for addressing the limitations of current antibody‐based detection methods. This report was prepared by the Working Group on Waterborne Cryptosporidiosis (Technical Task Force E, Developmental Status of Environmental Sampling, Water Testing, and Surrogate Indicators). Methods for detecting Cryptosporidium oocysts in water have centered around microscopic examination of fluorescent antibody‐stained concentrates from large‐volume water samples. The limitations of these antibody‐based methods include the need for experienced analysts, lengthy analytical time, expense, lack of specificity, erratic efficiency, low precision, and difficulty in determining viability. A number of methods, assays, and procedures that have the potential for ameliorating some of these limitations are currently being evaluated. How successful such processes will be remains to be demonstrated by the scientific community.

Detection of cryptosporidia and Cryptosporidium parvum oocysts in environmental water samples by immunomagnetic separation-polymerase chain reaction

“…This appeared to be the case particularly in water samples containing low numbers of oocysts, such as treated waters, underground and spring waters. The recovery ef®ciency of the classical method currently used to detect waterborne oocysts has often been reported to be low and extremely variable (Whitmore and Carrington 1993;Jakubowski et al 1996). For example, the clari®cation of water samples by a Percoll±sucrose density gradient contributes signi®cantly to losses of cryptosporidial oocysts.…”

Rapid identification of Giardia duodenalis by loop-mediated isothermal amplification (LAMP) from faecal and environmental samples and comparative findings by PCR and real-time PCR methods

“…The conventional diagnosis of Giardia in stool examinations are the antigen tests (ELISA) and microscopy of the iodine or immunofluorescence stained cysts (IFT) following the application concentration techniques such as zinc sulphate flotation, formol-ethyl sedimentation and centrifugation. For water samples, chemical flocculation, filtering, centrifugation and immunomagnetic separation (IMS) have been used in the last decade as advanced procedures for the detection of cysts (Jakubowski et al 1996;USEPA 2001;Plutzer et al 2008).…”

Protozoa in open reservoirs

“…The analytical method for Giardia and Cryptosporidium enumeration has been widely criticized as being inefficient, variable, cumbersome, labor‐intensive, time‐consuming, expensive, and analyst‐dependent 15 , 18 . Although alternative methods are under development, 19 consensus on a suitable replacement method has not been reached. In comparisons among 10 laboratories, median recovery efficiencies for Giardia and Cryptosporidium were 30 and 20 percent, with coefficients of variation of 77 and 106 percent, respectively 20…”