Evaluation of two isolates of the nematophagous fungus Duddingtonia flagrans in the control of infective larvae of Ancylostoma spp. dogs

Os nematóides do gênero Ancylostoma são endoparasitas de cães e também geohelmintos zoonóticos que podem infectar o ser humano. O controle destes nematóides em estágio adulto é baseado na utilização de anti-helmínticos. No entanto, o uso de agentes biocontroladores pode ser uma medida complementar para reduzir a população em estágios pré-parasitários em desenvolvimento no ambiente. Este estudo objetivou avaliar o fungo predador Duddingtonia flagrans no controle da forma larval infectante (L3) de Ancylostoma spp., em areia de praia. Foi avaliada a infectividade in vitro de dois isolados do fungo nematófago D. flagrans (AC001 e CG768) sobre larvas infectantes (L3) de Ancylostoma spp. de cães. Utilizou-se como inóculos fúngicos estruturas vegetativas (micélio), reprodutivas (conídios) e de sobrevivência (clamidósporos). A interação foi avaliada ao final de 10 dias de incubação em placas de Petri contendo meio ágar-água 2% em temperatura de 25 °C. O antagonismo em condições semi-naturais foi avaliado por meio da utilização de uma produção massal de inóculo fúngico em grãos de milho moído. O fungo foi incorporado à areia, em grãos colonizados de milho moído na concentração de 15.000 clamidósporos/grama de areia. Essa concentração se mostrou a mais efetiva em ensaio in vitro preliminar (redução de 59,2%). Os resultados mostraram a eficiência do fungo D. flagrans no controle de larvas infectantes de Ancylostoma spp. em areia de praia. Isso sugere que isolados desse fungo podem ser utilizados como parte de um programa de controle de Ancylostoma spp. no ambiente.The nematodes of the genus Ancylostoma are endoparasites of dogs and also zoonotic geohelminths that can infect humans. The control these nematodes in adult stage is based on the use of anthelmintics. However, the use of biocontrol agents may be an additional action to reduce the population in pre-parasitic stages developing in the environment. This study aimed to evaluate the Duddingtonia flagrans predator fungus for the control of the larval form (L3) of Ancylostoma spp., in beach sand. We evaluated the in vitro infectivity of two isolates of the nematophagous fungus D. flagrans (AC001 and CG768) on infective larvae (L3) of Ancylostoma spp. dogs. Vegetative structures (mycelium), reproductive (conidia) and survival (chlamydospores) were used as fungal inoculum. The interaction was evaluated at the end of 10 days of incubation in Petridishes containing agar-water 2% medium in a temperature of 25 ° C. The antagonism in semi-natural conditions was assessed by use of a mass production of fungal inoculum in grains of milled maize. The fungus was introduced into the sand in colonized milled maize at the concentration of 15,000 chlamydospores / gram of sand. This concentration was the most effective in the preliminary in vitro assay (reduction of 59.2%). The results showed the efficiency of the fungus D. flagrans in the control of infective larvae of Ancylostoma spp. in beach sand. This suggests that isolates of this fungus may be used as part of a control program of Ancylostoma spp. in the environment.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Biological control of infective larvae of Ancylostoma spp. in beach sand

Geohelminths are parasites that stand out for their prevalence and wide distribution, depending on the soil for their transmission. The aim of this work was to evaluate the predatory capacity of the fungal isolate of the genus Duddingtonia (CG768) on third stage larvae (L3) of Ancylostoma spp. in beach sand under laboratory conditions. In the assay A five treatment groups and 1 control group were formed. The treatment groups contained 5000, 10,000, 15,000, 20,000 or 25,000 chlamydospores of the fungal isolate and 1000 Ancylostoma spp. L3 in pots containing 30 g of sand. The control group (without fungus) contained only 1000 Ancylostoma spp. L3 and distilled water in pots with 30 g of sand. Evidence of predatory activity was observed at the end of 15 days, where we observed the following percentages of reduction of L3: Group 1 (4.5%); Group 2 (24.5%); Group 3 (59.2%); Group 4 (58.8%); Group 5 (63%). However, difference was noted (p < 0.01) only at concentrations 15,000, 20,000 and 25,000 in relation to control group. In the assay B two groups were formed in Petri dishes of 9 cm in diameter containing agar water 2% medium. In the treated group, each Petri dish contained 500 Ancylostoma spp. L3 and 5 g of sand containing the isolate CG 768 at a concentration of 25,000 chlamydospores/g of sand, and the control group (without fungus) contained only 500 L3. At the end of 7 days the non-predation L3 of Petri dishes using the method of Baermann were recovered. Difference (p < 0.01) between groups on reducing the average number of Ancylostoma spp. L3 (percent reduction of 84%) was observed. The results of this study confirm earlier work on the efficiency of the Duddingtonia genus in the control of Ancylostoma spp. infective larvae.Los geohelmintos son parásitos que destacan por su prevalencia y amplia distribución, puesto que su transmisión depende del suelo. El objetivo del presente estudio fue evaluar la capacidad predatoria de aislamientos fúngicos del género Duddingtonia (CG768) sobre las larvas de estadio 3 (L3) de Ancylostoma spp. en arena de playa, en condiciones de laboratorio. En el ensayo A se formaron 5 grupos de tratamiento y un grupo de control. Los grupos de tratamiento contenían 5000, 10.000, 15.000, 20.000 o 25.000 clamidosporas del aislamiento fúngico y 1000 larvas L3 de Ancylostoma spp. en recipientes con 30 g de arena. Los recipientes del grupo de control (sin clamidosporas) solo contenían 1000 larvas L3 de Ancylostoma spp. y agua destilada con 30 g de arena. Al término de 15 días, fue evidente la actividad predatoria, con los porcentajes siguientes de reducción de larvas L3: grupo 1 (4.5%); grupo 2 (24.5%); grupo 3 (59.2%); grupo 4 (58.8%), y grupo 5 (63%). Sin embargo, en relación con el grupo control, solo se identificaron diferencias significativas (p < 0.01) a las concentraciones de 15.000, 20.000 y 25.000. En el ensayo B, en placas de Petri de 9 cm de diámetro, que contenían un medio de agar agua al 2%, se formaron 2 grupos. En el grupo tratado, cada placa de Petri contenía 500 larvas L3 de Ancylostoma spp. y 5 g de arena con el aislamiento CG768 a una concentración de 25.000 clamidosporas/g de arena, y el grupo de control (sin hongo) solo contenía 500 larvas L3. Al cabo de 7 días, utilizando el método de Baermann, a partir de las placas de Petri se obtuvieron larvas L3 no sometidas a predación por el hongo. Entre los grupos se observó una diferencia significativa (p < 0.01) en la reducción del número medio de larvas L3 de Ancylostoma spp. (porcentaje de reducción del 84%). Los resultados del presente estudio confirman los datos de investigaciones previas sobre la eficiencia del género Duddingtonia en el control de las larvas infectantes de Ancylostoma spp

In vitro biological control of infective larvae of Ancylostoma ceylanicum

The aim of this study was to evaluate the predatory activity of the fungus Duddingtonia flagrans (AC001) on infective larvae of Ancylostoma ceylanicum after gastrointestinal transit in hamsters. Twenty animals were used in the experiment, divided into two groups: a treated group (10 animals) and a control group (10 animals). In the group treated with D. flagrans, each animal received mycelium from the AC001 isolate, at an oral dose of 5 mg/25 g of live weight. To evaluate the predatory activity of the fungus, fecal samples were collected from the animals in both groups, at the times of 6, 8, 12, 24 and 36 hours after the treatment. Then, subsamples of 2 g of feces were placed in Petri dishes containing 2% water-agar (2% WA) culture medium and 1000 L3 of A. ceylanicum. Over the study period, the following percentage reductions were observed: 43.2% (6 hours), 30.8% (8 hours), 25.8% (12 hours), 30% (24 hours) and 11% (36 hours). The fungus D. flagrans presented predatory activity on the L3 of A. ceylanicum, after passing through the hamsters' gastrointestinal tract. It was therefore concluded that the fungus D. flagrans may be an alternative for biological control of the L3 of A. ceylanicum.O objetivo deste trabalho foi avaliar a atividade predatória do fungo Duddingtonia flagrans (AC001) sobre larvas infectantes de Ancylostoma ceylanicum após o trânsito gastrintestinal em hamsters. Foram utilizados vinte animais no experimento, divididos em dois grupos: um grupo tratado (10 animais) e um grupo controle (10 animais). No grupo tratado com D. flagrans, cada animal recebeu 5mg/25g de peso vivo de micélio do isolado AC001, por via oral. Para avaliar a atividade predatória do fungo, amostras fecais foram coletadas de ambos os grupos de animais nos horários de: 6, 8, 12, 24 e 36 após o tratamento. A seguir, 2g de fezes foram colocadas em placas de Petri contendo o meio de cultura ágar-água 2% (AA2%) e 1000 L3 de A. ceylanicum. Ao longo dos horários estudados os seguintes percentuais de redução foram observados: 43,2% (6 horas); 30,8% (8 horas); 25,8% (12 horas); 30% (24 horas) e 11% (36 horas). O fungo D. flagrans (AC001) apresentou atividade predatória sobre as L3 de A. ceylanicum após o trânsito pelo trato gastrintestinal de hamsters. Além disso, foi observada uma diferença significativa nos percentuais obtidos de cada horário em relação ao numero de L3 recuperadas (P < 0,01). Conclui-se, portanto, que o fungo D. flagrans pode ser uma alternativa de controle biológico das L3 de A. ceylanicum

First report of the activity of predatory fungi on Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) first-stage larvae

The nematode Angiostrongylus cantonensis causes eosinophilic meningoencephalitis in humans and thus alternative methods of control should be studied. The objective of this work was to evaluate the predatory capacity of eight fungal isolates of the species Duddingtonia flagrans (AC001, CG768 and CG722), Monacrosporium thaumasium (NF34), M. sinense (SF53) and Arthrobotrys robusta (I31), A. cladodes (CG719) and A. conoides (I40) on first-stage larvae (L 1 ) of A. cantonensis under laboratory conditions. The treated groups contained 1000 conidia of the fungal isolates and 1000 A. cantonensis L 1 in Petri dishes containing 2% water-agar medium (2% WA). The control group (without fungi) contained only 1000 A. cantonensis L 1 in 2% WA. Evidence of predation was observed at the end of 7 days. Percentage reductions in L 1 were: AC001, 82.8%; CG768, 71.0%; CG722, 72.8%; NF34, 86.7%; SF53, 89.7%; I40, 48.3%; CG719, 84.7%; and I31, 80.4%. No significant difference was observed (p > 0.01) between the actions of the isolates used; however, a difference was noted (p < 0.01) in relation to the control group. The results of the present work, confirm previous reports of the effectiveness of the fungi D. flagrans, M. thaumasium, M. sinense and A. robusta in controlling larvae of potentially zoonotic nematodes, this being the first report on A. cantonensis L 1