Equine farming faces growing challenges with helminthoses, aggravated by the indiscriminate use of anthelmintics without technical criteria. This practice favors resistance to these drugs, generates residues in animal products, compromises food safety and human health, and, when excreted in large quantities, negatively impacts environmental health by affecting invertebrates and fecal microorganisms. This highlights the importance of the One Health approach. A promising alternative is biological control with nematophagous or helminthophagous fungi such as Duddingtonia flagrans, Pochonia chlamydosporia, Arthrobotrys oligospora, Monacrosporium thaumasium, Mucor circinelloides and Purpureocillium lilacinum. Due to their different mechanisms of action, ovicidal and predatory fungi, when used together, can act in a complementary and synergistic way in the biological control of helminths, increasing their effectiveness in reducing parasitic infections. The use of these fungi through biosynthesized nanoparticles from fungal filtrates is also emerging as a new approach to nematode control. It can be administered through feed supplementation in commercial formulations. The aim of this review is to explore the use of helminthophagous fungi in the control of helminthiases in horses, highlighting their potential as a biological alternative. It also aims to understand how these fungi can contribute effectively and sustainably to parasite management in horses.

Although microbial biopesticides are expanding rapidly, transforming nematophagous fungi into consistent and shelf-stable products remains a challenge. A key limitation is that fungal propagules must remain viable throughout production, storage, and delivery to ensure their efficacy in the field. This review examines formulation strategies that improve the stability, deployment, and performance of fungal biocontrol agents against gastrointestinal helminths in domestic animals and plant-parasitic nematodes. In veterinary systems, predatory fungi such as Duddingtonia flagrans primarily target infective larvae after surviving gastrointestinal transit and germination in feces. In contrast, ovicidal fungi, including Pochonia chlamydosporia, Purpureocillium lilacinum, Trichoderma spp., and Mucor spp., primarily act against helminth eggs and coccidian oocysts. This functional complementarity highlights the potential of combined fungal formulations to improve their control efficacy. We also discuss the currently available D. flagrans-based commercial products, BioWorma^® and Bioverm^®, and the practical challenges associated with dosing, administration, and farm adoption. In agriculture, we show that the Brazilian market is dominated by solid fungal nematicides designed to reduce water activity and prolong shelf life, although liquid- and oil-based systems remain relevant for specific applications. Across both sectors, the review identified formulation design, rather than fungal species alone, as a critical determinant of product performance. Emerging advances, such as microencapsulation, UV-protective matrices, improved seed-coating biopolymers, nanobiotechnology, and fungal-derived bioactive products, indicate that future progress will depend on target-oriented formulations capable of increasing stability, controlled release, and resilience under environmentally variable conditions, including those imposed by climate change.

Cattle ranching in Brazil has long been one of the main and most important sectors of the economy. Among the factors that negatively influence the rearing of production animals, the worm disease deserves prominence, because it is one of the most important problems of the Brazilian herd, being responsible for large losses in livestock activity. Worms are caused by helminths of different phyla, classes, genera and species, and can affect several animals, being extremely important in production animals. These parasites can cause losses and great economic losses due to the fall in animal production and costs with its control. The administration of anthelmintics in the correct dosage is of great importance, because its misuse is probably one of the causes that accelerate the emergence of resistant helminth populations. However, when done incorrectly and indiscriminately, it can lead to inefficiency of the drugs because with the wrong management of these drugs there is a selection of resistant parasites. In view of the above, the objective of this literature review was to gather information on ways to control helminthiases and some alternatives that have been studied to improve livestock production systems. Keywords: Anthelmintics; Helminths; Nematodes.

Objetivou-se avaliar o grau de helmintose, ganho de peso e parâmetros hematológicos de bezerros Nelore, fêmeas e machos, oriundos de matrizes do mesmo rebanho previamente classificadas por diferentes níveis de infecção parasitária. Os animais foram divididos conforme a classificação de suas mães, sendo filhos de resistentes (G1), resilientes (G2) e susceptíveis (G3). As fezes foram coletadas a cada 28 dias para a contagem de ovos por grama de fezes (OPG), coprocultura e identificação das larvas. As pesagens foram realizadas a cada 28 dias, após o desmame e as coletas de sangue, no início e no término do experimento para determinar o volume globular, proteína plasmática total e contagem de eosinófilos do sangue. O resultado obtido para OPG demonstrou que não houve diferença significativa entre G1, G2 e G3. No período de três a oito meses de idade, o OPG dos bezerros machos também não apresentou diferença entre os grupos, já as bezerras filhas de vacas previa[i]mente classificadas como susceptíveis (G3) apresentaram um OPG superior em relação às filhas das resistentes e resilientes (G1 e G2). Em relação ao peso, houve diferença significativa no GPD geral (machos e fêmeas), onde os animais do G3 apresentaram um menor GPD em relação aos demais grupos, já o G1 e G2 não apresentaram diferença significativa. Nos parâmetros hematológicos não houve diferença nos parâmetros avaliados. Nas coproculturas, em todos os grupos foram encontradas larvas de Cooperia spp., Haemonchus spp. e Oesophagostomum spp.. Conclui-se que bezerras filhas de vacas susceptíveis podem sofrer influência de suas mães em relação a carga parasitária e assim, redução em seu desempenho produtivo. Já bezerros machos não sofreram influência de suas mães no grau de helmintose e desempenho.