The nematode transmission of Toxoplasma gondii

Abstract

A cat infected with the nematode, Toxocara cati, and another which was nematode-negative, were both fed with the cystic forms of T. gondii. The cat infected with T. cati produced feces capable of infecting mice with Toxoplasma; the Toxocara-negative cat did not. The Toxocara-negative cat was then infected with this nematode and the positive cat was treated with an anthelmintic to remove the worms. Both cats were again fed with Toxoplasma cysts; the feces containing the Toxocara cati ova infected mice with Toxoplasma, while those negative for Toxocara did not. These experiments support the idea that T. gondii can be transmitted within T. cati ova. Additional support was provided by the fact that the toxoplasm infections can be filtered from a positive inoculum by using a sieve whose mesh size is small enough to retain the nematode ova. Evidence is given that this transmission mechanism could be responsible for avian infections.