Controle biológico de helmintos parasitos de animais: estágio atual e perspectivas futuras

Efficacy Evaluation of a Commercial Formulation With Duddingtonia Flagrans in Equine Gastrointestinal Nematodes

The indiscriminate use of antiparasitics for the treatment of helminths in horses has caused the ineffectiveness of commonly used chemical active principles, therefore, new alternatives such as the use of helminthophagous fungi have been studied. In this context, this study aimed to evaluate the in vitro efficacy of the commercial formulation Bioverm, composed of the fungus Duddingtonia flagrans strain AC001, in the reduction of gastrointestinal nematode larvae in equine feces. In coproculture, the genus Cyathostomum sp. was the most prevalent in the analyzed samples. The commercial formulation with D. flagrans demonstrated effectiveness in the predation of Cyathostomum sp. in tests. The recommended dose of 0.4 g, containing 105 chlamydospores per gram of product, reduced larvae by 44.23%, while the extrapolated dose of 1.0 g with the same concentrations of chlamydospores (105/g) resulted in a reduction of 57.20%, indicating the effectiveness of the product in controlling infective larvae.

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.

On the interactions involving serine proteases obtained from Monacrosporium thaumasium (Ascomycota: Orbiliomycetes) and deoxyribonucleic acid (DNA): biological macromolecules in action

The use of force spectroscopy approaches performed with optical tweezers can be very useful in determining the binding modes and the physical chemistry of DNA interactions with ligands, from small drugs to proteins. Helminthophagous fungi, on the other hand, have important enzyme secretion mechanisms for various purposes, and the interactions between such enzymes and nucleic acids are very poorly studied. Therefore, the main goal of the present work was to investigate, at the molecular level, the mechanisms of interaction between fungal serine proteases and the double-stranded (ds) DNA molecule. Experimental assays performed with this single molecule technique consist in exposing different concentrations of the protease of this fungus to dsDNA until saturation while monitoring the changes on the mechanical properties of the macromolecular complexes formed, from where the physical chemistry of the interaction can be deduced. It was found that the protease binds strongly to the double-helix, forming aggregates and changing the persistence length of the DNA molecule. The present work thus allowed us to infer information at the molecular level on the pathogenicity of these proteins, an important class of biological macromolecules, when applied to a target specimen.

Control of sheep gastrointestinal nematodes on pasture in the tropical semiarid region of Brazil, using Bioverm® (Duddingtonia flagrans)

We aimed to evaluate a Brazilian commercial formulation of the fungus Duddingtonia flagrans (Bioverm®) for controlling gastrointestinal nematodes in sheep kept on native pasture in the Caatinga biome, in the semiarid region of Brazil. Twenty ewes, aged between 12 and 18 months, were divided into two groups. In the treated group, each animal received 1 g of the Bioverm® product for each 10 kg of live weight, daily, together with commercial feed, for 6 months. In the control group, the animals received feed without Bioverm®. Each group remained throughout the experiment in a 1.2-ha paddock. Monthly counts of eggs per gram (EPG) of feces, fecal cultures, packed cell volume (PCV), weight measurements, and collection of leaf mass from the pasture were performed. There was greater reduction in EPG, greater weight gain, and less infestation by infective larvae in the paddock of the Bioverm® group, compared with the control group (p < 0.05). There was no significant difference (p ≥ 0.05) in the mean PCV percentage between the Bioverm® and control groups. In coprocultures, Haemonchus sp. was the most prevalent helminth. Bioverm® (D. flagrans) was efficient for biological control of sheep gastrointestinal nematodes in the semiarid region of Brazil.

Predatory activity of nematophagus fungus Duddingtonia flagrans in infective larvae after gastrointestinal transit: biological control in pasture areas and in vitro

Biological control is a strategy to decrease parasitic populations, and the action takes place through natural antagonists in the environment. We studied the predatory activity of the fungus Duddingtonia flagrans in infective larvae (L3) of gastrointestinal nematodes after gastrointestinal transit. Ten heifers were divided into two groups: treated (animals received pellets containing fungus) and control (animals received pellets without fungus). Twelve hours after administration, faeces samples were collected for in vitro efficacy tests. The animals then remained for 7 h in the experimental pasture area. At the end of this period, 20 faecal pads (ten treated and ten control) were selected at random. Pasture, faecal pad and soil collections occurred with an interval of 7 days, totalling four assessments. In vitro activity demonstrated that fungi effectively preyed on L3, achieving a reduction percentage of 88%. In the faecal pad of the pasture area, there was a difference (P < 0.05) between collections 3 and 4 for both groups; in the treated group a reduction of 65% was obtained, while in the control group there was an increase of 217% in the number of L3. The recovery of L3 in the soil and in the pasture was similar in both groups. There was no influence (P = 0.87) of the passage time on the fungus predatory activity. Duddingtonia flagrans demonstrated the ability to survive gastrointestinal transit in the animals, reducing the number of L3 in the faeces, indicating that this biological control has great potential in the control of worm infections.

Efficacy of a commercial fungal formulation containing Duddingtonia flagrans (Bioverm®) for controlling bovine gastrointestinal nematodes

Bioverm® (Duddingtonia flagrans) is a fungal formulation indicated for controlling gastrointestinal nematodes in ruminants and horses, which has recently been authorized for commercialization in Brazil. The objective was to determine the efficiency of Bioverm® against larvae of gastrointestinal nematodes after passage through the gastrointestinal tract of cattle. Twelve animals were used, divided into two groups. In the treated group, a single dose of 1 g of Bioverm® per 10 kg of live weight (containing 105 chlamydospores of D. flagrans) was provided for each animal. Fecal samples were obtained from the animals in each group at 12, 24, 36, 48, 60 and 72 hours after administration. In assay A, 2 g of feces were added to Petri dishes containing 2% agar-water medium. In assay B, coprocultures were performed. In both assays, the peak of larval predation occurred within 48 hours after administration of Bioverm®. In assay A, a significant larval reduction (P < 0.05) was seen at 48 h (88.2%). In assay B, significant reductions (P < 0.05) were seen at 36 h (43.7%) and 48 h (82.3%). Bioverm® showed high predatory capacity after passage through the gastrointestinal tract of cattle and was effective for controlling gastrointestinal nematodes.

Arthrobotrys cladodes and Pochonia chlamydosporia: Nematicidal effects of single and combined use after passage through cattle gastrointestinal tract

Nematodiosis are responsible for financial losses in cattle production systems due to treatment costs, falling production rates and animal deaths. The incorporation of sodium alginate pellets containing nematophagous fungi in the bovine diet is a method for the control of nematodiosis. The aims of this study were to evaluate the viability of Arthrobotrys cladodes and Pochonia chlamydosporia contained in sodium alginate pellets after passage through the bovine gastrointestinal tract, as well as to evaluate the effects of single and combined use of these fungi against bovine parasitic nematodes. The reduction in parasitic nematode infective larvae of bovines by the combined use of Arthrobotrys cladodes and Pochonia chlamydosporia was more than the reduction in infective larvae by Arthrobotrys cladodes or Pochonia chlamydosporia alone in the collections 12, 24 and 36 h after giving the pellets to the animals. Arthrobotrys cladodes and Pochonia chlamydosporia combined promoted maximum reduction of infective larvae of 86.3%. Therefore, the combination of Arthrobotrys cladodes and Pochonia chlamydosporia may be an effective method to control gastrointestinal nematodiosis affecting grazing cattle.

Efficiency of the Bioverm ® (Duddingtonia flagrans) fungal formulation to control in vivo and in vitro of Haemonchus contortus and Strongyloides papillosus in sheep

The objective of the present work was to evaluate the efficiency of Bioverm® fungal formulation (Duddingtonia flagrans-AC001) in controlling Haemonchus contortus and Strongyloides papillosus in sheep. In vitro predation tests were carried out in Petri dishes containing agar culture medium 2%. Four experimental groups were formed, with five replicates each: Group 1: 1 g of Bioverm ® and 1000 third-stage larvae (L3) of H. contortus; Group 2: 1000 L3 of H. contortus; Group 3: 1 g of Bioverm ® and 1000 L3 of S. papillosus; and Group 4: 1000 L3 of S. papillosus. In the in vivo tests, twelve 11-month-old sheep males positive for H. contortus were used. The animals were sorted in two groups (treatment and control), based on fecal egg counts (eggs per gram, EPG). Each group comprised six animals: treatment group-each animal received orally 100 g of Bioverm ® ; and control group-each animal received orally 100 g of rice. Subsequently, feces from these animals were collected at 12, 24, 36, 48, 60, 72, 84, and 96 h after Bioverm ® administration. In vitro results demonstrate that D. flagrans kept its predatory activity with 91.5% of mean reduction percentage of L3. After the passage test, Bioverm ® presented efficacy already after 12 h of its administration and kept similar results for 60 h. Bioverm® fungal formulation (D. flagrans-AC001) was efficient in reducing the population of H. contortus and S. papillosus under laboratory conditions in sheep feces. However, further studies are needed under natural conditions of ruminant grazing to prove the efficiency of this product.

Predatory effect of Duddingtonia flagrans on infective larvae of gastro-intestinal parasites under sunny and shaded conditions

Duddingtonia flagrans is a natural strain of Nematophagous-Fungi isolated around the world. It has demonstrated efficacy and ease of use in laboratory as well as in field conditions. The fungus contributes to the prophylactic control of the worms by reducing the number of L₃ on pasture. The aims of this study were to test and analyze the predatory effect of D. flagrans under sunny and shaded conditions on the L₃ in the faeces, and to verify the reduction of translation to pasture during summer and winter seasons. Faecal Mass Units (FMUs) were assigned to two treated groups (groups treated with D. flagrans chlamydospores, TG) and two untreated groups (without D. flagrans chlamydospores, UG), in summer and winter, under sunny and shaded conditions. FMUs and herbage samples were taken for parasitological workup. Predatory activity of D. flagrans was evident under both conditions for the summer experiment but was not manifest for the winter experiment. In summer, an interaction between sunny and shaded conditions and predatory activity of D. flagrans was found. Environmental conditions on predatory activity should be considered when designing strategies for the implementation of D. flagrans in grazing systems to smooth the infectivity curve of L₃.

In vitro and in vivo studies of nematophagous fungi Arthrobotrys musiformis and Arthrobotrys robusta against the larvae of the trichostrongylides

Six isolates of Arthrobotrys musiformis and five isolates of Arthrobotrys robusta were assessed in in vitro test regarding the capacity of prey larvae of the natural mixed trichostrongylides. In 5 isolates of A. robusta, the decrease percentage of infective larvae (L3) of trichostrongylides ranged from 97.71%-99.98% and for the isolates of A. musiformis, 5 isolates ranged from 97.99%-99.95% and only NF015 isolate 60.72%. In the following, the isolate (NPS045) of A. musiformis was selected to assess its excretion time in feces after oral administration of goats. Regarding L3 reduction rate, results demonstrated by NPS045 at each time point after fungal administration were 31.65% (12 h), 51.25% (24 h), 41.07% (48 h), 6.44% (72 h), 0% (96 h) and (120 h) (p<0.05) respectively, when compared to the control group. In the plates of the treated groups, the presence of the isolate (NPS045) was detected in samples at 12, 24 and 48 h after the fungus dose and 72 h later was not done. All native isolates of nematophagous fungi, including 6 isolates of A. musiformis and 5 isolates of A. robusta were assessed in vivo regarding the capacity of supporting the passage through goat gastrointestinal tract. The 3 isolates of A. musiformis could be able to pass through the digestive tract of goats without complete loss of ability of preying larvae of trichostrongylides in feces and their efficacies ranged from 47.60% to 55.93%. The two isolates of A. robusta survived the passage and the percentage reduction of L3 in feces were 41.96% and 66.97%, respectively. The remaining isolates were negative for both the efficacy of L3 reduction and the fungal examination in feces. In this study, the native isolates whose efficacies are good in vivo test have preliminarily demonstrated to be potential for the biological control of small ruminant parasite.

Duddingtonia flagrans no controle de nematoides gastrintestinais de equinos em fases de vida livre

RESUMO O objetivo deste estudo foi avaliar a atividade predatória do fungo Duddingtonia flagrans contra larvas infectantes (L3) de nematoides gastrintestinais na pastagem e no bolo fecal de equinos, em um período de 21 dias. O delineamento experimental foi inteiramente ao acaso, com três grupos tratados (G1, G2 e G3) e um controle (C), com oito animais/grupo. Os tratados receberam 1,5x105; 3x105 e 6x105 clamidósporos de D. flagrans/kg-1peso vivo animal, G1, G2 e G3, respectivamente, durante 21 dias, com administração a cada três dias. Foram delimitadas 36 áreas de 1m2 cada, equivalendo a repetições em triplicata para cada grupo. As fezes foram coletadas dos animais nos dias 0 (D0), 15 (D15) e 30 (D30 = sete dias após a última administração dos tratamentos) e depositadas nessas áreas de pastagem. O número de larvas presentes nos bolos fecais e na pastagem foi avaliado após 14 e 21 dias de cada etapa de deposição. A avaliação da atividade predatória de D. flagrans na pastagem e nos bolos fecais demonstrou que a redução do número de L3 nos bolos fecais foi acompanhada pelo aumento da variável na pastagem. Não se constatou diferença significativa entre os grupos avaliados em decorrência da temperatura média registrada durante o período. As avaliações realizadas em um curto período podem ser insuficientes para a avaliação do efeito do fungo.

Larvicidal activity of Bacillus circulans against the gastrointestinal nematode Haemonchus contortus in sheep

Efficient control of gastrointestinal parasites is necessary in sheep breeding. However, the available chemically based anthelmintics are becoming less effective due to the development of parasite resistance. An alternative to this problem is biological control. In the present study, we tested the larvicidal effect of Bacillus circulans by administering a spore suspension (2 × 109 colony forming units/ml) orally to lambs naturally infected with Haemonchus contortus. The number of faecal larvae was quantified daily and a significant reduction (~87%, P< 0.05) of larval development was observed after administration of B. circulans. Using a transformed B. circulans with green fluorescent protein, we were able to detect B. circulans in the faeces at 4 h post-administration and 72 h after cessation of its administration. These results suggest the use of B. circulans as a promising biological alternative for parasite control.

In vitro susceptibility of nematophagous fungi to antiparasitic drugs: interactions and implications for biological control

Abstract The fast anthelmintic resistance development has shown a limited efficiency in the control of animal’s endoparasitosis and has promoted research using alternative control methods. The use of chemicals in animal anthelmintic treatment, in association with nematophagous fungi used for biological control, is a strategy that has proven to be effective in reducing the nematode population density in farm animals. This study aims to verify the in vitro susceptibility of the nematophagous fungi Arthrobotrys oligospora, Duddingtonia flagrans and Paecilomyces lilacinus against the antiparasitic drugs albendazole, thiabendazole, ivermectin, levamisole and closantel by using the Minimum Inhibitory Concentration (MIC). MICs ranged between 4.0 and 0.031 µg/mL for albendazole, thiabendazole and ivermectin, between 0.937 and 0.117 µg/mL for levamisole, and between 0.625 and 0.034 µg/mL for closantel. The results showed that all antiparasitic drugs had an in vitro inhibitory effect on nematophagous fungi, which could compromise their action as agents of biological control. D. flagrans was the most susceptible species to all drugs.

Duddingtonia flagrans in the control of gastrointestinal nematodes of horses

Horses can harbor a large amount of parasites that may cause serious clinical signs even death. The aim of this study was to evaluate the predatory activity of the fungus Duddingtonia flagrans against infective larvae (L3) of gastrointestinal nematodes of horses in fecal culture. The experimental design was completely randomized with three treated groups (G1, G2 and G3) and one control (CG), using eight animals/group. The treated animals received G1: 1.5 × 10(5); G2: 3 × 10(5) and G3: 6 × 10(5) chlamydospores of D. flagrans/kg body weight during 21 days. The fungi preparation was given at every other three-day interval. Faecal samples were collected during 30 days, on the same interval, to perform the fecal egg counts (EPG) and fecal culture for each horse. All groups demonstrated similar results for the EPG (P > 0.05) counts. D. flagrans significantly reduced (P < 0.05) the number of infective larvae after 72 h-interval between treatments. The G2 and G3 promoted higher results (P < 0.05) of L3 reduction compared to the CG. The biological control with the predacious fungi D. flagrans is still a promising free-living parasite regulator alternative to be use in livestock.

Predatory capability of the nematophagous fungus Arthrobotrys robusta preserved in silica gel on infecting larvae of Haemonchus contortus

Biological control of gastrointestinal nematodiasis in ruminants is an alternative to reduce the number of infective larvae. The fungal isolates predatory activity preservation is a basic requirement for the success of this control type. The aim of this work is to evaluate the predatory capacity of the fungus Arthrobotrys robusta (isolate I-31), preserved on silica gel on infective larvae of Haemonchus contortus under laboratory conditions on 2 % water agar (2 % WA). In this essay, A. robusta storage on silica gel showed successful predatory activity on H. contortus L3 larvae (p < 0.01) compared to the control group. Nematophagous fungi were not observed in the control group during the experiment. There was a significant reduction (p < 0.01) of 73.84 % in the means of H. contortus (L3) recovered from treatment with isolate I-31 compared to the control without fungi. Results indicate that A. robusta (I-31) could survive stored on silica gel for at least 7 years and keep its predatory activity on H. contortus (L3).

The nematophagous fungus Monacrosporium thaumasium and its nematicidal activity on Angiostrongylus vasorum

BACKGROUND

The dog acts as a reservoir and environmental disseminator of potentially zoonotic parasites.

AIMS

The objective of this work was to study the fungus Monacrosporium thaumasium regarding its nematicidal potential in laboratory trials and its proteolytic profile.

METHODS

The in vitro test was carried out through two assays (A and B). In assay A, conidia of the fungus N34a were added in positive coprocultures for Angiostrongylus vasorum. In assay B, crude extract (treated group) and distilled water (control group) were added to coprocultures. Next, the proteolytic profile of crude extract of the nematophagous fungus M. thaumasium (NF34a) was revealed by performing a zymogram.

RESULTS

There was a reduction (p<0.01) in the averages of larvae recovered from the treated groups (conidia and crude extract) in relation to control groups. The zymogram suggested that the nematophagous fungus M. thaumasium produces a protease of approximately 40 kDa.

CONCLUSIONS

The results of this work confirm that the conidia as well as the crude extract of the fungus M. thaumasium may be used to control A. vasorum L1. The proteolytic profile suggested the presence of one protease (Mt1) of approximately 40 kDa that in the future may be used in biological control of L1 of this nematode.

Ocorrência das doenças parasitárias em ovinos e caprinos no Distrito Federal, Brasil, durante 2003 a 2009

O parasitismo é um dos principais fatores limitantes na produção animal em geral. A ovinocultura e caprinocultura são afetadas por diversos parasitas que representam significativas perdas em carne, leite e lã da cultura. A introdução recente de ovinos e caprinos no Centro-Oeste brasileiro trouxe consigo novas enfermidades antes não relatadas na região. O objetivo deste estudo é descrever a ocorrência dos principais parasitas que afetam os caprinos e ovinos no Distrito Federal e região do entorno e os fatores predisponentes destas enfermidades ao rebanho local, revisando os casos obtidos pela necropsia dos animais no período de 2003 a 2009. Nos meses de outubro de 2009 a julho de 2010 foram revistos os laudos de necropsia da região, em retrospectiva dos anos de 2003 a 2009, à procura das casuísticas por doenças parasitárias. Verificou-se a ocorrência de endoparasitoses e ectoparasitoses em pequenos ruminantes. Os principais parasitas encontrados foram o Haemonchus contortus e Oestrus ovis nas duas culturas, porém Oesophagostomun sp. ocorreu apenas em ovinos. Encontrou-se maior ocorrência de Haemonchose na estação chuvosa do Cerrado. Este é o primeiro trabalho epidemiológico descritivo sobre parasitismo em cabras e ovelhas na região.

Inovações tecnológicas na caprinocultura

O largo crescimento do setor de agronegócios no Brasil tem estimulado mudanças nos sistemas produtivos, tanto na intensificação, como na profissionalização da produção. Dessa forma, os produtores têm buscado estratégias para melhor atender aos desafios da atividade pecuária atual, dentre as quais se destacam as inovações tecnológicas que devem resultar em comprovado benefício à atividade, seja pelo aumento em produtividade, seja pela melhoria na qualidade dos produtos, seja pela conscientização do respeito ao meio ambiente. Assim como em outros segmentos do agronegócio brasileiro, na caprinocultura existe uma demanda crescente pela aplicação de inovações tecnológicas, uma vez que o sistema produtivo precisa ser mais competitivo para se manter no mercado. Dentre as inovações tecnológicas aplicadas na caprinocultura, foram abordadas as mais relevantes nas áreas de reprodução (desde métodos para indução de cio até a prática da transgenia), melhoramento genético (biogenética), sanidade (inovações no diagnóstico e prevenção de doenças de maior impacto na criação), nutrição (inovações nos sistemas de alimentação) e tratamento de dejetos (diminuição de contaminantes no ambiente). A utilização conjunta das inovações tecnológicas nos diferentes segmentos associados à cadeia produtiva caprina pode fazer com que ocorram melhorias nos rebanhos assim como nos produtos gerados.

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.

[Destruction of Strongyloides venezuelensis infective larvae by fungi Duddingtonia flagrans, Arthrobotrys robusta and Monacrosporium sinense]

INTRODUCTION

Strongyloides venezuelensis has been used as a model for studying human strongyloidosis.

METHODS

This study aimed to compare the ability of predatory nematophagous fungi Duddingtonia flagrans (AC001), Arthrobotrys robusta (I-31) and Monacrosporium sinense (SF53) and on infective larvae (L3) of Strongyloides venezuelensis in laboratory conditions on 2% water-agar medium.

RESULTS

At the end of the experiment, the percentage reductions of Strongyloides venezuelensi L3 were: 93% (AC001), 77.2% (I-31) and 65.2% (SF53).

CONCLUSIONS

The nematophagous fungi were able to capture and destroy the L3 in vitro and can be used as biological controllers of Strongyloides venezuelensi.

Predatory activity of nematophagous fungi on infective larvae of Ancylostoma sp.: evaluation in vitro and after passing through the gastrointestinal tract of dogs

The predatory capacity of nematophagous fungi Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34a), M. appendiculatum (CGI), M. sinense (SF53), Arthrobotrys conoides (I-40), A. cladodes (CG719) and A. robusta (I-31) on infective Ancylostoma sp. larvae (L3) was evaluated. Compared with the control without fungi there was a significant reduction (P < 0.05) of 87.02%, 82.74%, 47.93%, 60.49%, 76.89%, 71.33% and 86.02% in the mean number of Ancylostoma sp. (L3) recovered from treatments with the isolates AC001, NF34a, CGI, SF53, I-40, CG719 and I-31, respectively. Isolates AC001, I-31 and NF34a were more effective in capturing L3 during the in vitro assay. Isolates were then in vivo evaluated for the capacity to remain viable after passing through the gastrointestinal tract of dogs, while still maintaining their predatory activity against L3. Fungal isolates survived the passage and showed efficient predation 48 h after fungal administration to the dogs (P < 0.05). After this time, only the isolate NF34a remained effective up to 96 h after administration (P < 0.05). Monacrosporium thaumasium, D. flagrans and A. robusta are potential biological control agents of Ancylostoma sp. in dogs.

Predatory activity of the fungi Duddingtonia flagrans, Monacrosporium thaumasium, Monacrosporium sinense and Arthrobotrys robusta on Angiostrongylus vasorum first-stage larvae

Angiostrongylus vasorum is a nematode that parasitizes domestic dogs and wild canids. We compared the predatory capacity of isolates from the predatory fungi Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34), Monacrosporium sinense (SF53) and Arthrobotrys robusta (I31) on first-stage larvae (L1) of A. vasorum under laboratory conditions. L1A. vasorum were plated on 2% water-agar (WA) Petri dishes marked into 4 mm diameter fields with the four grown isolates and a control without fungus. Plates of treated groups contained each 1000 L1A. vasorum and 1000 conidia of the fungal isolates AC001, NF34, SF53 and I31 on 2% WA. Plates of the control group (without fungus) contained only 1000 L1A. vasorum on 2% WA. Ten random fields (4 mm diameter) were examined per plate of treated and control groups, every 24 h for 7 days. Nematophagous fungi were not observed in the control group during the experiment. There was no variation in the predatory capacity among the tested fungal isolates (P>0.05) during the 7 days of the experiment. There was a significant reduction (P < 0.05) of 80.3%, 74.5%, 74.2% and 71.8% in the means of A. vasorum L1 recovered from treatments with isolates AC001, NF34, SF53 and I31, respectively, compared to the control without fungi. In this study, the four isolates of predatory fungi were efficient in the in vitro capture and destruction of A. vasorum L1, confirming previous work on the efficiency of nematophagous fungi in the control of nematode parasites of dogs and as a possible alternative method of biological control.

Efeito do fungo Paecilomyces lilacinus sobre ovos de Taenia saginata

Com o objetivo de demonstrar a eficácia do fungo Paecilomyces lilacinus sobre ovos de Taenia saginata em condições laboratoriais, foi montado ensaio em placas de Petri com agar - água 2%. Houve atividade ovicida (p<0,05) em relação ao grupo controle no décimo dia de interação e colonização interna dos ovos de 25,5%.

Ovicidal activity of Paecilomyces lilacinus on Moniezia sp. eggs

The ovicidal activity of Paecilomyces lilacinus was evaluated on Moniezia sp. eggs. Eggs of Moniezia sp. were incubated on plates with 2% agar-water inoculated with grown fungal isolates and a control treatment without fungus. After 5, 10 and 15 days post-inoculation, the eggs were removed and classified according to the following parameters: effect type 1, lytic effect without morphological damage to eggshells; effect type 2, lytic effect with morphological change in embryos and eggshells; and effect type 3, lytic effect with morphological change in embryos and eggshells, with hyphal penetration and internal colonization of eggs. Paecilomyces lilacinus showed percentages for ovicidal activity (P < 0.01), mainly type 3 effect, of 19, 20 and 23% on eggs of Moniezia sp., after 5, 10 and 15 days post-inoculation, respectively. Therefore P. lilacinus can be considered as a potential biological control agent for this cestode.

In vitro evaluation of the effect of the nematophagous fungi Duddingtonia flagrans, Monacrosporium sinense, and Pochonia chlamydosporia on Ascaris suum eggs

The in vitro effect of four isolates of the nematophagous fungi Duddingtonia flagrans (AC 001), Monacrosporium sinense (SF 53), and Pochonia chlamydosporia (VC 1 and VC 4) on eggs of Ascaris suum was evaluated. One hundred thousand A. suum eggs were plated on 2% water-agar with the grown isolates and control without fungus. After 7, 14, and 21 days, 100 eggs were removed and classified according to the following parameters: type 1, lytic effect without morphological damage to eggshell; type 2, lytic effect with morphological alteration of embryo and eggshell; and type 3, lytic effect with morphological alteration of embryo and eggshell, besides hyphal penetration and internal egg colonization. P. chlamydosporia showed ovicidal activity (p < 0.01), mainly of the type 3 effect, on A. suum eggs in the studied intervals of 13.3% (isolate VC 1) and 17.3% (isolate VC 4), 13.9% (VC 1) and 17.7% (VC 4), and 19% (VC 1) and 20% (VC4), respectively, at 7, 14, and 21 days. The other fungi showed no type 3 effect. P. chlamydosporia is a potential biological control agent of A. suum eggs.