Potential Usefulness of Filamentous Fungi to Prevent Zoonotic Soil-Transmitted Helminths.

The usefulness of a strategy involving the biological control of soil-transmitted helminths (STHs) with zoonotic potential is tested. A blend of spores of two filamentous fungi, Mucor circinelloides and Duddingtonia flagrans, was provided to one group (G-2) of puppies (five Griffon bleu de Gascogne and five Gascon Saintongeois) shedding eggs of Toxocara canis, Toxascaris leonina, Trichuris vulpis, and Ancylostoma caninum. Other identical group (G-1) remained without spores. Fecal samples were collected daily and divided into two portions, one sample was immediately analyzed by the flotation test and the other was examined 28 days later. Viability of eggs of T. canis, T. leonina, and T. vulpis in fecal pats was ascertained by microscopic examination; the numbers of larvae of A. caninum were assessed in each group. In the feces of G-2, spores of both fungi were observed 1 day after beginning the assay. Viability of eggs of T. canis was reduced by 57%, T. leonina by 61% and T. vulpis by 53% in the fecal pats of G-2, and by 87%, 92%, and 85%, respectively, in G-1. The numbers of third-stage larvae of A. caninum were 59% lower in G-2 than that in G-1. By considering the results obtained and the absence of adverse effects in the puppies of G-2, it is concluded that the presence of the filamentous fungi in the feces has a high potential to avoid the transmission of these parasites. Further studies are in progress to determine the appropriate way of administration to pets.