EN
In a field experiment conducted near Poznan (Poland) eggs of Ascaris suum were found to have penetrated the soil according to the dispersion of percolating water which depends mainly on the soil structure and texture. Under natural conditions, after 17 months, the eggs were recovered in soil down to a depth of 8-21 cm. Out of the 50,000 Ascaris eggs used for contamination of each soil sample only 0. 1-4.5% survived for 17 months in the larval stage and most of these remained within 1-5 cm of the soil surface. It was observed that some of the eggs may have their development temporarily arrested.