Improved methods for recovering eggs of Toxocara canis from soil

The ingestion of soil in parks and public places containing eggs of Toxocar a may constitute a significant health risk, particularly to children. To de termine the most efficient method for extracting eggs from experimentally c ontaminated soil, two consecutive studies were undertaken. Four techniques, including washing, sieving, vacuum, and the one recommended by the World H ealth Organization, were evaluated. Recovery rates of over 85% were recorde d with both washing and sieving methods. Using the washing technique, all c ombinations of the four pre-treatment solutions, distilled water, acetoacet ic solution pH 5, 0.1 N sodium hydroxide and 1% Tween 20, and seven flotati on fluids with different specific gravities (S.G.) ranging from 1.20 to 1.3 5 were assayed. The association of distilled water and saccharose solution with an S.G. of 1.27 showed the best results, with a recovery rate of 99.91 %.