Interaction of the nematophagous fungusPochonia chlamydosporiaandParascaris equorumeggs in different culture media

Assessing the applications and efficacy of using helminthophagous fungi to control canine gastrointestinal parasites

Helminths are a major challenge in dog breeding, particularly affecting young animals and posing a significant zoonotic risk. The widespread use of anthelmintics to treat gastrointestinal helminth infections in companion animals is common. However, these chemical products generate residues that can have adverse effects on animal, human and environmental health. In addition to the challenge of parasite resistance to treatment, there is an urgent need to explore and discuss complementary and sustainable methods of controlling helminthiases in these animals. In this context, nematophagous or helminthophagous fungi have emerged as a potential tool for the control of environmental forms of helminths. The purpose of this review is to emphasize the importance of these fungi in the control of free-living forms of helminth parasites in companion animals by highlighting the research that has been conducted for this purpose. In vitro experiments demonstrated the efficacy of fungi like Pochonia chlamydosporia, Arthrobotrys robusta, and Monacrosporium thaumasium in trapping and reducing helminth infective forms. These findings, along with soil contamination studies, suggest the feasibility of using helminthophagous fungi as a sustainable and effective strategy for environmental control. The current literature supports the potential of these fungi as an environmentally friendly solution for managing helminthiasis in dogs, benefiting both animal health and public welfare.

Nematophagous fungus Pochonia chlamydosporia to control parasitic diseases in animals

The control of gastrointestinal parasites in animals has become more challenging every year due to parasite resistance to conventional chemical control, which has been observed worldwide. Ovicidal or opportunistic fungi do not form traps to capture larvae. Their mechanism of action is based on a mechanical/enzymatic process, which enables the penetration of their hyphae into helminth eggs, with subsequent internal colonization of these. The biological control with the Pochonia chlamydosporia fungus has been very promising in the treatment of environments and prevention. When used in intermediate hosts of Schistosoma mansoni, the fungus promoted a high percentage decrease in the population density of aquatic snails. Secondary metabolites were also found in P. chlamydosporia. Many of these compounds can be used by the chemical industry in the direction of a commercial product. This review aims to provide a description of P. chlamydosporia and its possible use as a biological parasitic controller. The ovicidal fungus P. chlamydosporia is effective in the control of parasites and goes far beyond the control of verminosis, intermediate hosts, and coccidia. It can also be used not only as biological controllers in natura but also as their metabolites and molecules can have chemical action against these organisms. KEY POINTS: • The use of the fungus P. chlamydosporia is promising in the control of helminths. • Metabolites and molecules of P. chlamydosporia may have chemical action in control.

Efficacy of a Fungal Formulation with the Nematophagous Fungus Pochonia chlamydosporia in the Biological Control of Bovine Nematodiosis

In the control of bovine worms, biological control by nematophagous fungi stands out, especially Pochoniachlamydosporia which causes the destruction of helminth eggs. This study aims to test the effectiveness of a formulation containing the nematophagous fungus Pochonia chlamydosporia isolated for the biological control of bovine nematodiosis. Twelve cattle were divided into two groups: control group (GC) and the group that received the formulation (GT). Feces and pasture samples were collected for the research of gastrointestinal nematodes. Lung worms and trematodes were investigated. The animals were weighed monthly. The averages of temperature and rainfall were recorded. The supply of the fungus Pochonia chlamydosporia was not effective in reducing the eggs per gram of feces of gastrointestinal nematodes (EPG) of the animals, not differing statistically (p > 0.05) between the groups. The mean values of larvae recovered in the pasture did not differ significantly (p > 0.05). The genus Haemonchus sp. was the most prevalent. There was no correlation between the number of larvae with temperature and rainfall (p > 0.05). There was a statistically significant difference (p < 0.05) in the penultimate weighing of the experiment. The formulation containing Pochonia chlamydosporia was not efficient in the biological control of bovine gastrointestinal nematodes.

Individual and Combined Application of Nematophagous Fungi as Biological Control Agents against Gastrointestinal Nematodes in Domestic Animals

Gastrointestinal nematodes (GINs) are a group of parasites that threaten livestock yields, and the consequent economic losses have led to major concern in the agricultural industry worldwide. The high frequency of anthelmintic resistance amongst GINs has prompted the search for sustainable alternatives. Recently, a substantial number of both in vitro and in vivo experiments have shown that biological controls based on predatory fungi and ovicidal fungi are the most promising alternatives to chemical controls. In this respect, the morphological characteristics of the most representative species of these two large groups of fungi, their nematicidal activity and mechanisms of action against GINs, have been increasingly studied. Given the limitation of the independent use of a single nematophagous fungus (NF), combined applications which combine multiple fungi, or fungi and chemical controls, have become increasingly popular, although these new strategies still have antagonistic effects on the candidates. In this review, we summarize both the advantages and disadvantages of the individual fungi and the combined applications identified to date to minimize recurring infections or to disrupt the life cycle of GINs. The need to discover novel and high-efficiency nematicidal isolates and the application of our understanding to the appropriate selection of associated applications are discussed.

In Vitro Inhibiting Effects of Three Fungal Species on Eggs of Donkey Gastrointestinal Strongyles

Recently, donkeys have gained popularity mainly due to the use of donkey milk by the cosmetic industry and for human consumption. Gastrointestinal strongyles (GIS) are considered a potential cause of disease and reduced production in infected donkeys. European laws limit the use of anthelmintic drugs for the control of GIS in dairy donkey farms, thus the need to develop alternative control methods. This study aimed to test the in vitro inhibiting effects of three chitin degrading fungi (Scopulariopsis brevicaulis, Metarhizium anisopliae, and Beauveria bassiana) on the hatch and viability of donkey GIS eggs by using the egg hatch test, and to compare their activity to that of Pochonia chlamydosporia. About 150 eggs were added to 0.5 mL of sterile saline solution containing about 1.4 × 10⁸ spores of each fungal species or with 0.5 mL of sterile saline solution only (untreated controls). After incubation, the percentage of egg hatch reduction was calculated, and data were statistically analyzed. All fungi were able to significantly reduce (p < 0.05) the hatch of GIS eggs compared to the untreated controls. Further studies that aim to investigate the efficiency of these fungi in reducing donkey GIS eggs in contaminated environments are encouraged.

Isolation of Ovicidal Fungi from Fecal Samples of Captive Animals Maintained in a Zoological Park

There are certain saprophytic fungi in the soil able to develop an antagonistic effect against eggs of parasites. Some of these fungal species are ingested by animals during grazing, and survive in their feces after passing through the digestive tract. To identify and isolate ovicidal fungi in the feces of wild captive animals, a total of 60 fecal samples were taken from different wild animals kept captive in the Marcelle Natureza Zoological Park (Lugo, Spain). After the serial culture of the feces onto Petri dishes with different media, their parasicitide activity was assayed against eggs of trematodes (Calicophoron daubneyi) and ascarids (Parascaris equorum). Seven fungal genera were identified in the feces. Isolates from Fusarium, Lecanicillium, Mucor, Trichoderma, and Verticillium showed an ovicidal effect classified as type 3, because of their ability to adhere to the eggshell, penetrate, and damage permanently the inner embryo. Penicillium and Gliocladium developed a type 1 effect (hyphae attach to the eggshell but morphological damage was not provoked). These results provide very interesting and useful information about fungi susceptible for being used in biological control procedures against parasites.

Feeding horses with industrially manufactured pellets with fungal spores to promote nematode integrated control

The usefulness of pellets industrially manufactured with spores of parasiticide fungi as a contribution to integrated nematode control was assessed in grazing horses throughout sixteen months. Two groups of 7 Pura Raza Galega autochthonous horses (G-T and G-P) were dewormed pour-on (1mg Ivermectin/kg bw) at the beginning of the trial, and other group (G-C) remained untreated. The G-P was provided daily with commercial pellets to which was added a mixture of fungal spores during the industrial manufacturing (2×10⁶ spores of Mucor circinelloides and same dose of Duddingtonia flagrans/kg), and G-T and G-C received pellets without spores. The efficacy of the parasiticidal strategy was assessed by estimating the reduction in the faecal egg counts (FECR) and in the number of horses shedding eggs in the faeces (PHR), and also the egg reappearance periods (ERP). Blood analyses were performed to identify the changes in the red and white cell patterns. To ascertain if horses developed an IgG humoral response against the fungi, antigenic products collected from M. circinelloides and D. flagrans were exposed to the horse sera by using an ELISA. The faecal elimination of eggs of Parascaris equorum and strongyles ceased 2 weeks after treatment in G-T and G-P, thus the values of FECR and PHR were 100%. No P. equorum-eggs were detected later, and the strongyle egg reappearance period was 28 weeks in G-P, and 8 weeks in G-T. Strongyle egg-output values remained lower than 300 eggs per gram of faeces in the G-P, whereas numbers between 330 and 772 in G-C and G-T were recorded. Normal values for the erythrocytes, haemoglobin and haematocrit in horses consuming pellets with spores were recorded, and lower than normal in the other groups. Sensitization of horses to the fungal species was disproven. It is concluded that feeding horses with pellets industrially manufactured with fungal spores represents a very useful tool to implement an integrated control of helminths affecting horses. This strategy allows a decrease in their risk of infection, aids in reducing the frequency of anthelmintic treatment.