[Influence of zinc and lead ions on the development of eggs of Ascaris suum (Nematoda)].

The objective of this work was to examine the influence of heavy metals ions, zinc and lead, in external environment on the development of Ascaris suum to invasive stage. The culture mediums contained 25.5, and 0.5 mM Pb(NO3)2 or ZnSO4. After 6 weeks of development in 26 degrees C in the control 75.17% of eggs reached the invasive stage. Ions of lead and zinc, in a way depending on concentration inhibited development of embryos. The invasive stage in the presence of 25.5 and 0.5 mM Pb(NO3)2 were achieved by 37.89% , 44,75% and 64.63% of eggs and in ZnSO4 solutions with the same concentrations of ions 45.40%, 50.36% and 66.61% respectively. Many of eggs in 25 mM solutions of both metals stopped at the blastula stage.