Migration of some roundworm species in experimentally infected white mice.

The migration of four roundworm species (Ascaris suum, Toxocara canis, T. cati and Toxascaris leonina) was studied in various organs of experimentally infected white mice. The hatching of T. leonina and T. cati larvae in the paratenic host is more rapid (24-36 h) than the hatching of A. suum and T. canis larvae (1-6 days). The deposition of larvae in host organs is different in the individual species. Maximum number of larvae in the liver: T. leonina and A. suum on day 4, T. canis on day 2 and T. cati on day 1. Maximum number of larvae in the lungs: A. suum and T. leonina on day 7, T. cati on day 2 and T. canis on day 1. Maximum number of larvae in muscles: A. suum on day 21 only rarely, T. canis and T. cati on day 3 and T. leonina on day 28. In the brain occurred mostly the larvae of T. canis and a lower number of T. cati larvae, whereas the other two nematode species did not occur at all in this organ.