[Quantitative demonstration of helminth stages in municipal waste water]

Quantitative estimation of helminth stages in municipal waste waters. A method for the quantitative estimation of helminths eggs in municipal waste waters is described. The method is based on a modified flotation pattern combining both more accurate determination of the percentage of eggs and minimal microscopic examination. The percentage of recovery was found to increase proportionally to the egg content of the sample. Therefore, the methodological error does not represent a constant. For getting comparable data on the contents of helminth eggs, the median or the geometrical mean should be calculated instead of the arithmetical mean usually applied.