A Comparison of Enumeration Techniques for Cryptosporidium parvum Oocysts

A variety of methods have been used to enumerate Cryptosporidium parvum oocysts from source or drinking waters. The reliability of these counting methods varies, in part, with suspension density, sample purity, and other factors. Frequently, the method of determination of suspension density is not r...

Full description

Saved in:

Bibliographic Details
Published in:	The Journal of parasitology Vol. 85; no. 6; pp. 1165 - 1168
Main Authors:	Bennett, Jason W., Gauci, Mark R., Le Moënic, Steven, Schaefer, Frank W., H. D. Alan Lindquist
Format:	Journal Article
Language:	English
Published:	Lawrence, KS American Society of Parasitologists 01-12-1999
Subjects:	Animals Biological and medical sciences Chemical suspensions Cryptosporidium parvum Cytometry Environmental agencies Flow Cytometry - methods Fundamental and applied biological sciences. Psychology General aspects and techniques Infections Liver Microbiology Microscope slides Oocysts Parasite Egg Count - methods Parasites Parasitology Protozoa Research Notes Water - parasitology Infection Cryptosporidiosis Drinking water Protozoal disease Enumeration Methodology Parasite Parasitosis Technique Comparative study Oocyst Cell density
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	A variety of methods have been used to enumerate Cryptosporidium parvum oocysts from source or drinking waters. The reliability of these counting methods varies, in part, with suspension density, sample purity, and other factors. Frequently, the method of determination of suspension density is not reported by authors. To confound the problem, each method of counting has large inherent variation. There is a relationship between suspension density, overall number of organisms counted, and counting mechanism accuracy that should be accounted for when selecting a counting mechanism. This study selected a maximum acceptable coefficient of variation (CV) to be 10%. A method was considered unreliable if this standard was not achieved. Flow cytometry achieved this standard at 486 oocysts/ml. Counting with a Coulter counter achieved this level of reliability at about 1,230 oocysts/ml. Neither chamber slides nor fluorescent antibody-stained well slides ever demonstrated less than 10% CV. However, estimates of the minimum required concentrations were 5,100 oocysts/ml and approximately 6,500 oocysts/ml, respectively. The hemacytometer provided counts accurate to a 10% CV at a concentration of at least 60,000 organisms/ml. Of the methods tested, flow cytometry provided the least amount of variability at low suspension densities.
Bibliography:	ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2
ISSN:	0022-3395 1937-2345
DOI:	10.2307/3285681