Survival of larvae of Nippostrongylus brasiliensis (nematoda) in solutions of toxic substances.

The aim of this study was to determine the action of zinc, copper, lead and cadmium compounds upon N. brasiliensis invasive nematode larvae. The tested larvae were kept in ZnCl2, CuCl2, Pb(NO3)2 and CdCl2 solutions. The concentrations of toxic substances applied for the study corresponded with level of environmental pollution. All toxins reduced life-space of larvae. In control group they survived about 69 days. In solutions of the Zn, contaminated with 10, 50, 100 and 200 ppm of toxic substance, they survived 42, 16, 14 days and 72 hours. In solution of Cu, contaminated with 5, 10, 50 and 200 ppm of toxin, life--space was reduced to 51, 21, 7 days and 54 hours, respectively. Lead reduced live--space of larvae to 26 days already at the low concentration of 10 ppm and in all higher concentrations (20, 50 and 200 ppm) their survival changed insignificantly (to 22 days). In solution of Cd, contaminated with 0.1 and 0.3 ppm larvae died after 39 and 17 days, respectively, while at higher concentrations of this toxin (3 and 10 ppm) larvae survived only 54 and 30 hours, respectively.