Effect of zinc on invasive capacity and reproduction of Nippostrongylus brasiliensis (Nematoda) in rats.

The influence of zinc on the invasive capacity and reproduction of Nippostrongylus brasiliensis nematodes was examined in three successive generations: P-the larvae which were exposed to zinc solution (in the concentration of 50 ppm), and F1 and F2 derived from these intoxicated larvae. Migration and settlement capacity were defined by the number of larvae in lungs 24 hours post infection (hpi), and the number of adult nematodes in the small intestine 96, 114 and 236 hpi. Reproduction capacity was defined by the number of eggs in 1 g of faeces of infected rats. The invasive capacity of larvae declined in relation to control (C) group in all examined generations of N. brasiliensis. Surprisingly the decline was the lowest in generation P (directly intoxicated) and the greatest in generation F2. Reproduction of the nematodes declined considerably in P and F1, being similar in these two generations, while in F2 it was higher than in two former generations, and almost the same as in group C.