学会誌「EICA」

[特集] クリプトスポリジウムの環境水からの検出法

内容

バイオアッセイ

巻

9巻1号2004年

Page

15

題名

クリプトスポリジウムの環境水からの検出法

Title

Detection of Cryptosporidium from Environmental Water

著者

木村明生（大阪府立公衆衛生研究所）

Authors

著者表記

Author attribution

著者勤務先名

Office name

著者所属名

キーワード

Key Words

Cryptosporidium oocysts, Detection method, Environmental water, Monitoring

概要

クリプトスポリジウムは原虫とよばれる寄生性の原生動物である．分類学上はマラリア原虫やトキソプラズマと同じ，アピコンプレックス門，胞子虫網に属する．
本原虫には現在までに少なくとも10 種あることが判明しており，Tab.1 に示すようにほ乳類を始め，鳥類や爬虫類などの多種多様な動物種に自然感染している．

Abstract

　　Cryptosporidium is parasitic protozoa recognized to be the one of the
most important waterborne
pathogen. Since 1985, outbreaks of Cryptosporidiosis had been reported in many
countries, including USA, UK, Australia and Japan. In these cases, infections were caused
by drinking water contaminated by C. parvum oocysts. Currently water treatment plants in
developed countries are monitoring the contamination of Cryptosporidium in drinking water
sources as a daily routine work. Generally, the detection method of oocysts from environmental
water includes 3 steps, 1) concentration of large volume of water, 2) isolation and
recovery of oocysts from concentrated materials and 3) staining and microscopic detection of
oocysts. In the first step, commonly filtration methods are used. The filters currently used
are, hydrophobic PTEF filter (membrane filter : JAWA method, in JAPAN), CrypTestTM
(capsule filter : USEPA method 1623, in USA) or Filta-MaxTM (foam discs multiple layer
filter : DETR method SI.1524, in UK). The flocculation method or the continuous flow
centrifugation method could be used alternatively to filtration. In the second step, sucrose
flowtation or /and immunnomagnetic separation (IMS) are used. Finally oocysts are stained
by immuno fluorescein labeled monoclonal antibodies and screened under fluorescein microscope.
The detection of small numbers of oocysts from large volume of water needs time
consuming and labor intensive works and also well experienced skills. Research works to
develop simple, easy and sensitive detection methods are still on going.