RESUMEN El objetivo fue determinar la respuesta parasitológica e inmune en caballos reinfectados naturalmente con nematodos gastrointestinales (NGI) posterior a la desparasitación en el trópico húmedo de México. El estudio se realizó en Tenosique, Tabasco, México. Se utilizaron 30 caballos muestreados mensualmente durante nueve meses. Se determinó el número de huevos por gramo de heces (HPG). Se realizaron coprocultivos para obtener e identificar larvas infectivas (L3). Se obtuvieron muestras de sangre para determinar el volumen celular aglomerado (VCA), proteína plasmática (PPT) y el conteo diferencial de leucocitos (CDL). Se realizaron ensayos de inmuno absorción enzimática (ELISA) en suero para determinar los niveles de IgA contra antígenos de Ciatostómidos y de Strongylus. Los análisis consideraron la edad y el género, también se estudió la época (fría, lluviosa y seca). El número de HPG y PPT fueron más altos en las hembras (1224 ± 1269 y 7.6 ± 0.6 gdL-1, respectivamente) que en los machos (623 ± 671 y 7.4 ± 0.5 gdL-1, respectivamente), y no se observaron diferencias con la edad del animal (p > 0.05). El número de HPG aumentó en la temporada de lluvias. Los principales nematodos fueron de la subfamilia Cyathostominae (97.4%) y en menor grado las especies Strongylus equinus, S. edentatus, S. vulgaris, y Oxyuris equii. La época afectó el conteo de leucocitos, neutrófilos y linfocitos, pero no eosinófilos. Las variables como el género, edad animal y las condiciones ambientales son elementos a considerar para un diagnóstico de NGI y la aplicación de tratamientos para su control.

ABSTRACT The objective of the study was to determine the parasitological and immune response in horses naturally re-infected with gastrointestinal nematodes (GIN) after anthelmintic treatment in the humid tropic of Mexico. The study was conducted in Tenosique, Tabasco, Mexico. A total of 30 horses were sampled monthly for nine months. Fecal samples were obtained to determine the number of nematode eggs per gram (EPG) of feces. Stool cultures were performed to obtain and identify infective larvae (L3) genera. Blood samples were also obtained to determine the packed cell volume (PCV), the total plasma protein (TPP), and the differential leukocyte count (DLC). Serum enzyme-linked immunosorbent assays (ELISA) were performed to determine IgA levels against adult cyathostomins and Strongylus nematode antigen. The analyses considered the age and gender of the horses, and the season (Cold, rainy and dry). The number of EPG and TPP were higher in females (1224 ± 1269 and 7.6 ± 0.6 gdL-1, respectively) than males (623 ± 671 and 7.4 ± 0.5 gdL-1, respectively), and no differences were observed with animal age (p > 0.05). The number of EPG increased in the rainy season. The main nematodes involved were of the subfamily Cyathostominae (97.4%) and to a lesser degree of species Strongylus equinus, S. edentatus, S. vulgaris, and Oxyuris equii. The season affected the leukocytes, neutrophils, and lymphocytes counts but not eosinophils. Variables such as gender, animal age, and environmental conditions are important elements for a diagnosis of GIN and the application of treatments for its control.

Resumo O objetivo deste estudo foi avaliar a atividade predatória do nematoide Butlerius spp. e isolados fúngicos de Duddingtonia flagrans, Clonostachys rosea, Arthrobotrys musiformis e Trichoderma esau contra larvas infectantes (L3) de Haemonchus contortus em vasos plantados com Panicum spp. Foram utilizados quarenta e oito potes plásticos de jardinagem contendo 140 g de solo estéril, 200 mg de sementes de Panicum spp.. Cultivar colonião, foi semeado em cada vaso e, diariamente, molhados com 10 mL de água da torneira. Doze dias após, os vasos foram divididos em 6 grupos (n = 8), e duas mil L3 de H. contortus foram adicionadas a cada vaso. Foram estabelecidos os seguintes tratamentos: Grupo 1 - 2.000 larvas de Butlerius spp.; Grupo 2 - A. musiformis (1x107 conídios); grupo 3 - T. esau (1x107 conídios); grupo 4 - C. rosea (1x107 conídios); grupo 5 - D. flagrans (1x107conidia); e Grupo 6 – somente L3 de H. contortus que serviu como controle negativo. A população de L3 de H. contortus expostas a Butlerius spp. foi reduzida em 61,9%. Redução populacional de 90,4, 66,7, 61,9 e 85,7% foram observadas nos vasos contendo A. musiformis, T. esau, C. rosea e D. flagrans, respectivamente. Os resultados deste estudo indicaram que o nematoide Butlerius spp. e os fungos avaliados exibiram importante atividade predatória e podem ser considerados como agentes de controle biológico.

Abstract The purpose of this study was to evaluate the predatory activity of the nematode Butlerius spp. and fungal isolates of Duddingtonia flagrans, Clonostachys rosea, Arthrobotrys musiformis and Trichoderma esau against H. contortus infective larvae (L3) in grass pots. Forty-eight plastic gardening pots containing 140 g of sterile soil were used. Panicum spp. grass seeds (200 mg) were sown into each pot and individually watered with 10 mL of tap water. Twelve days after seeding, the pots were randomly divided into 6 groups (n=8). Two thousand H. contortus infective larvae (L3) were added to each group. Additionally, the following treatments were established: Group 1 – 2000 Butlerius spp. larvae; group 2 – A. musiformis (1x107 conidia); group 3 – T. esau (1x107 conidia); group 4 – C. rosea (1x107 conidia), group 5 – D. flagrans (1x107conidia) and Group 6 – no biological controller (control group). The larval population of H. contortus exposed to Butlerius spp. was reduced by 61.9%. Population reductions of 90.4, 66.7, 61.9 and 85.7% were recorded in the pots containing A. musiformis, T. esau, C. rosea and D. flagrans, respectively. The results of this study indicate that the predatory nematode Butlerius spp. and the assessed fungi display an important predatory activity can be considered suitable potential biological control agents.