Efficacy of Intestinal Scraping Technique in the Detection of Echinococcus Multilocularis - Estimation of the Limit of the Detection and Comparison with Sedimentation and Counting Technique

The aim of the study was to estimate the effectiveness of intestinal scraping technique (IST) in the detection of Echinococcus multilocularis. The experimental assessment of the limit of detection and comparison with “gold standard” (sedimentation and counting technique - SCT) was also performed. Samples of fox small intestines experimentally enriched with known numbers of E. multilocularis tapeworms, were used. Twenty four samples containing 10, 30, 60, and 90 E. multilocularis tapeworms were prepared. Moreover, in order to compare IST with SCT, 127 intestines of foxes were examined using both methods. The limit of detection was estimated at 30 E. multilocularis tapeworms per sample of the intestine. Moreover, mean number of Echinococcus found by IST were several dozen times lower than the real content of these tapeworms in the samples (on average only 2 to 3.2% of worms were recovered). Among 127 intestinal samples examined with the use of two methods, eight samples (8.2%) were positive by SCT and only two (1.6%) when IST was used. A relatively high limit of detection estimated experimentally in the first part of the study, as well as, the results obtained in field investigations showed clearly that IST method could significantly decrease the reliability of the results of investigations, especially carried out in regions where a very low prevalence of E.multilocularis occurs or in countries, which want to demonstrate that they are free from this parasite.