The Control of Zoonotic Soil-Transmitted Helminthoses Using Saprophytic Fungi

Abstract

Soil-transmitted helminths (STHs) are parasites transmitted through contact with soil contaminated with their infective eggs/larvae. People are infected by exposure to human-specific species or animal species (zoonotic agents). Fecal samples containing eggs of Ascaris suum or Lemurostrongylus sp. were sprayed with spores of the soil saprophytic filamentous fungi Clonostachys rosea (CR) and Trichoderma atrobrunneum (TA). The antagonistic effect was assessed by estimating the viability of eggs and their developmental rate. Compared to the controls (unexposed to fungi), the viability of the eggs of A. suum was halved in CR and decreased by two thirds in TA, while the viability of the eggs of Lemurostrongylus sp. was reduced by one quarter and one third in CR and TA treatments, respectively. The Soil Contamination Index (SCI), defined as the viable eggs that attained the infective stage, reached the highest percentages for A. suum in the controls after four weeks (66%), with 21% in CL and 11% in TA. For Lemurostrongylus sp., the values were 80%, 49%, and 41% for control, CR and TA treatments, respectively. We concluded that spreading spores of C. rosea or T. atrobrunneum directly onto the feces of animal species represents a sustainable approach under a One Health context to potentially reduce the risk of zoonotic STHs in humans.

Control of Strongyles in First-Season Grazing Ewe Lambs by Integrating Deworming and Thrice-Weekly Administration of Parasiticidal Fungal Spores

“…Monosporic cultures were obtained on potato glucose agar for morphometric and cultural characterization. Both M. circinelloides and D. flagrans were cultured in a submerged medium in the Laboratory of the COPAR Research Group (GI-2120; University of Santiago de Compostela, Spain) to obtain high numbers of chlamydospores [31,32].…”

Formulating Parasiticidal Fungi in Dried Edible Gelatins to Reduce the Risk of Infection by Trichuris sp. among Continuous Grazing Bison

“…Consequently, the oral administration of spores of parasiticide fungi offers a very helpful procedure to ensure that the antagonistic agents are in close contact with the eggs, regardless of their position. This has a significant advantage over other application methods, such as spraying directly on soil or feces [20,21,30].…”

“…was based on their ability to destroy them or damage them permanently (ovicide effect), as well as to influence the capability of the eggs to develop to the infective stage (ovistatic effect). In this way, eggs of Trichuris were sorted firstly into non-viable and viable, with respect to the observation of at least one disturbance, including shell disruption or contraction, cytoplasm vacuolization, or larval immobility when light stimulated (presence = non-viable; absence = viable) [21] (Figure 3). The ovicidal effect or viability reduction (VR) was assessed weekly by comparing the number of viable eggs in the feces with fungi (FF) and those in the controls (CF) (1):…”

The Use of Pythium oligandrum in the Biological Control of Roundworm Infection in Dogs and Cats

“…The short period of time chosen for conducting the research (according to the manufacturer) does not fully explain this phenomenon. According to a recent study from 2020 [ 20 ], in the case of A. suum , L1 is formed inside the eggs at 14 days and L2 after about 21 days. The highest percentage of eggs with L2 appears after 28 days.…”