Combined use of chemical and biological compounds to control hookworm.

The aim of this study was to evaluate the combined use of different chemical (albendazole, ivermectin, glycerine and Vaseline) and biological (Monacrosporium thaumasium) compounds in the control of Ancylostoma caninum. Infective larvae of A. caninum were obtained from coprocultures of positive faeces from naturally infected dogs. We used 1% ivermectin, 1% albendazole, 100% glycerine, 100% Vaseline and an isolate of the nematophagous fungus M. thaumasium (NF34), alone or in combinations. Next, an experimental test was set up with 16 groups in microtubes, with a 24-h interaction. The groups (G1 to G15) that contained any chemical or biological compound (NF34) and/or their combined use (chemical + biological) showed a difference in relation to the control group, except G5 - Vaseline 100% without combinations. It was concluded that, even on an experimental basis, the combined use of anthelmintic drugs with biological control was efficient; however, more studies must be carried out in order to elucidate the synergistic action between chemical and biological compounds to be used in the effective control of hookworms in the future.

An isolate of the nematophagous fungus Monacrosporium thaumasium for the control of cattle trichostrongyles in south-eastern Brazil.

A mycelial formulation in sodium alginate pellets of the nematophagous fungus Monacrosporium thaumasium (isolate NF34A) was assessed in the biological control of beef cattle trichostrongyles in tropical Brazil. Two groups of ten male Nellore calves aged 6 months, a fungus-treated group and a control group, were fed on a pasture of Brachiaria decumbens naturally infected with larvae of cattle trichostrongyles. The fungus-treated group received doses of sodium alginate mycelial pellets orally (1 g pellets (0.2 g fungus)/10 kg live weight) twice a week for 12 months. At the end of the study there was a significant reduction (P< 0.01) in the number of eggs per gram of faeces and coprocultures of the fungus-treated group--47.8% and 50.2%, respectively--in relation to the control group. There was a 47.3% reduction in herbage samples, collected up to 0-20 cm from faecal pats, between the fungus-treated and control groups, and a 58% reduction when the sampling distance was 20-40 cm from faecal pats (P< 0.01). The treatment with sodium alginate pellets containing the nematode-trapping fungus M. thaumasium reduced trichostrongyles in tropical south-eastern Brazil and could be an effective tool for the biological control of this parasitic nematode in beef cattle. However, in such a tropical climate with low rainfall the fungal viability can be reduced.

Parasitism by Paratanaisia bragai (Digenea, Eucotylidae) in commom waxbill (Estrilda astrild) / Parasitismo por Paratanaisia bragai em bico-de-lacre (Estrilda astrild)

O trematodeo digenético Paratanaisia bragai é descrito como parasito dos túbulos coletores renais e ureteres de aves. Esse helminto é usualmente pouco patogênico para a maioria dos hospedeiros; porém, em altas cargas parasitárias e em animais mais suscetíveis, pode causar sérios danos que resultam em apatia, perda de peso, desidratação e até mesmo a morte. O presente trabalho objetivou relatar pela primeira vez o trematoide P. bragai parasitando os rins de um passeriforme da espécie Estrilda astrild, conhecido popularmente como bico-de-lacre, de distribuição cosmopolita. A partir da análise histopatológica dos rins da ave, observou-se a presença dos vermes adultos e de ovos, grande dilatação dos ductos coletores renais, destruição e achatamento das células epiteliais de revestimento e, ao redor dos parasitos, observou-se moderada reação inflamatória. Os autores sugerem que a infecção pode ter sido acidental, uma vez que os moluscos terrestres que servem de hospedeiros intermediários para P. bragai não fazem parte da dieta natural descrita para os bico-de-lacre. Os resultados encontrados no presente estudo confirmaram um bico-de-lacre como possível hospedeiro de P. bragai, acrescentando essa espécie de ave e possivelmente todo o grupo dos passeriformes na epidemiologia da infecção por esse trematoide.(AU)

Novel porous scaffolds of pH responsive chitosan/carrageenan-based polyelectrolyte complexes for tissue engineering.

Polyelectrolyte complexes (PECs) represent promising materials for drug delivery and tissue engineering applications. These substances are obtained in aqueous medium without the need for crosslinking agents. PECs can be produced through the combination of oppositely charged medical grade polymers, which include the stimuli responsive ones. In this work, three-dimensional porous scaffolds were produced through the lyophilization of pH sensitive PECs made of chitosan (CS) and carrageenan (CRG). CS:CRG molar ratios of 1:1 (CSCRG1), 2:1 (CSCRG2), and 3:1 (CSCRG3) were used. The chemical compositions of the PECs, as well as their influence in the final structure of the scaffolds were meticulously studied. In addition, the pH responsiveness of the PECs in a range including the physiological pH values of 7.4 (simulating normal physiological conditions) and 4.5 (simulating inflammatory response) was assessed. Results showed that the PECs produced were stable at pH values of 7.4 and under but dissolved as the pH increased to nonphysiological values of 9 and 11. However, after dissolution, the PEC could be reprecipitated by decreasing the pH to values close to 4.5. The scaffolds obtained presented large and interconnected pores, being equally sensitive to changes in the pH. CSCRG1 scaffolds appeared to have higher hydrophilicity and therefore higher water absorption capacity. The increase in the CS:CRG molar ratios improved the scaffold mechanical properties, with CSCRG3 presenting the higher compressive modulus under wet conditions. Overall, the PEC scaffolds appear promising for tissue engineering related applications that require the use of pH responsive materials stable at physiological conditions.

Pochonia chlamydosporia in the biological control of Fasciola hepatica in cattle in Southeastern Brazil.

Biological control with the use of nematophagous fungi has been described very successfully by many authors and presents itself as a complementary control method, acting on the free-living forms of helminths. The efficacy of a formulation containing the fungus Pochonia chlamydosporia in controlling Fasciola hepatica eggs in faeces was evaluated in an experimental field assay. Two bovine groups (six animals each) were used: A (control) and B (treated with fungus). At 30 days after deworming, the animals were separated into two similar paddocks with flooded areas and were given pellets containing 25 % mycelial mass (group B) or no fungus (group A) at a dose of 1 g/10 kg body weight, twice a week, during 18 months. Faecal samples were harvested fortnightly in the animals of groups A and B and they were submitted at examination of quantitative sedimentation. The mean count of F. hepatica eggs per grams of faeces was significantly higher in group A (1.19) compared with those from group B (0.82) (P < 0.01). After 18 months, animals from group B had gained 42.33 kg above (17.82 % more by weight) (P < 0.01), compared with the control group (A). Every month, faecal samples from paddocks A and B were collected and they were incubated. P. chlamydosporia was identified only in sample source of the paddock B. It can be concluded that the application of this fungical formulation with P. chlamydosporia 25 % mycelial mass was effective in reducing the availability of eggs in the environment and reinfections in calves in natural conditions.

Comparison between the action of nematode predatory fungi Duddingtonia flagrans and Monacrosporium thaumasium in the biological control of bovine gastrointestinal nematodiasis in tropical southeastern Brazil.

Sodium alginate pellets of the nematode predatory fungi Duddingtonia flagrans and Monacrosporium thaumasium were evaluated in the biological control of bovine gastrointestinal nematodiasis. Three groups (A-C) of ten six month old male Nelore bulls were kept in paddocks of Brachiaria decumbens for 12 months. Each animal of group A received 1g/10 kg of body weight (b.w.) of pellets of D. flagrans (0.2 g of fungus/10 kg b.w.) and of group B, 1g/10 kg of b.w. of pellets of M. thaumasium (0.2 g of fungus/10 kg b.w.), twice a week, for 12 months. Animals of the group control received no fungus. The monthly averages of egg count per gram of feces of the animals of groups A and B were 56.67% and 47.8% smaller, than the animals of group C (p<0.05), respectively. Treatment of bulls with pellets containing the nematophagous fungi D. flagrans and M. thaumasium can be used as an alternative treatment of bovine gastrointestinal nematodiasis, however, D. flagrans was more efficient than M. thaumasium for the biological control in the environmental conditions of the present study.

Alternativas para o controle de nematoides gastrintestinais de pequenos ruminantes / Alternative techniques for the control of gastrointestinal nematodes in small ruminants

Sheep and goat farming requires an efficient management program, due to losses caused by parasites in susceptible animals. Many factors may collaborate to improve infection tolerance in the herd, such as: genetics, nutrition, physiological status, and age. The problem caused by resistance to antihelmintic agents has led to the spread of alternative techniques for parasite controls. The latest strategies include selective treatment with the FAMACHA method, phytotherapy, biological control with predatory fungi, and strategies that still await scientific confirmation, such as homeopathy, the dilution of resistance with the introduction of susceptible parasites, and the combination of drugs without antihelmintic effect. The main objective of these methods is to reduce the usage of antiparasitic agents, thus slowing the development of resistance and promoting the better use of effective products and newly released products. The objective of this article is to describe techniques for controlling nematodes in small ruminants, and it is aimed at technicians interested in increasing their knowledge about the mechanisms of resistance to antihelmintic agents as well as alternatives to the use of these products.

A criação de ovinos e caprinos depende de um manejo eficiente, devido, principalmente, ao prejuízo causado por parasitos em animais susceptíveis. Vários fatores colaboram para que os animais tolerem as infecções parasitárias, como: genética, nutrição, estado fisiológico e idade. O grave problema causado pela resistência anti-helmíntica promoveu a difusão de técnicas alternativas de controle parasitário. Dentre essas novas estratégias incluem-se a adoção do tratamento parcial seletivo com o método FAMACHA, fitoterapia, controle biológico com o uso de fungos nematófagos e estratégias que ainda necessitam de mais dados como a homeopatia, a diluição da resistência com a introdução de parasitos sensíveis e a combinação de produtos químicos sem efeito antiparasitário. O objetivo central destes métodos é reduzir o uso de antiparasitários, retardando o desenvolvimento da resistência, e promover melhor utilização de produtos ainda eficazes na propriedade e de novos produtos que venham a ser lançados. Este artigo abordará as técnicas descritas acima para o controle de nematoides de pequenos ruminantes e é direcionado aos técnicos interessados em ampliar seu conhecimento sobre os mecanismos de resistência dos parasitos aos anti-helmínticos e de alternativas ao uso desses produtos.

First report of austrodiplostomum compactum and ithyoclinostomum dimorphum in trahira (hoplias malabaricus) from the middle course of the Rio Doce, Minas Gerais, Brazil / Primeiro relato de austrodiplostomum compactum e ithyoclinostomum dimorphum em traíras (hoplias malabaricus) provenientes do médio curso do rio doce, Minas Gerais, Brasil

Austrodiplostomum compactum and Ithyoclinostomum dimorphum are two trematodes commonly found in trahira, but these parasites were never reported in trahiras from Rio Doce. Thus, the aim of this study is to describe the occurrence of A. compactum and I. dimorphum metacercariae in trahira from the middle course of the Rio Doce and to record the presence of eggs in I. dimorphum metacercariae. The parasites were identified and analyzed using methods described previously. There were found 10 A. compactum metacercariae in the aqueous humor of eyes in four of the trahiras and 12 I. dimorphum metacercariae encysted in the peritoneal cavity in five of the trahiras. Maceration of the I. dimorphum metacercariae revealed the presence of eggs. These results demonstrate the broad distribution of these parasites and the first report of these parasites in trahira from Rio Doce.

Austrodiplostomum compactum e Ithyoclinostomum dimorphum são dois trematódeos comumente encontrados em traíras, contudo, esses parasitas nunca foram relatados em traíras do Rio Doce. O objetivo do estudo é descrever a ocorrência de metacercárias de A. compactum e I. dimorphum, e presença de ovos em metacercárias de I. dimorphum em traíras provenientes do médio curso do Rio Doce. Os parasitas foram analisados e identificados utilizando métodos descritos anteriormente. Foram encontradas 10 metacercárias de A. compactum no humor aquoso dos olhos em quatro traíras e 12 metacercárias de I. dimorphum encistadas na cavidade peritoneal de cinco traíras. A maceração de metacercárias de I. dimorphum revelou a presença de ovos nestes parasitos. Esses resultados demonstram a ampla distribuição desses trematódeos e este é o primeiro relato destes parasitos em traíra do Rio Doce.

Biological control of trichostrongyles in beef cattle by the nematophagous fungus Duddingtonia flagrans in tropical southeastern Brazil.

The efficacy of a fungal formulation based on the nematophagous fungus Duddingtonia flagrans was assessed in the control of cattle trichostrongyles. Twenty male Nellore calves, six-month-old, divided in two groups (fungus-treated and control without fungus) were fed on a pasture of Brachiaria decumbens naturally infected with larvae of bovine trichostrongyles. Animals of the treated group received doses of sodium alginate mycelial pellets orally (1 g/10 kg live weight, twice a week), for 12 months. Feces samples were collected for egg count (eggs per gram of feces-EPG) and coprocultures during 12 months. There was a significant reduction in EPG (56.7%) and infective larvae (L3) in coprocultures (60.5%) for animals of the treated group in relation to the control group at the end of the study. There was a significant reduction of L3 (64.5%) in herbage samples collected up to 0-20 cm from fecal pats and 73.2% in distant samples (20-40 cm) between the fungus-treated group and the control group. The treatment with sodium alginate pellets containing the nematode trapping fungus D. flagrans reduced trichostrongylid in tropical southeastern Brazil and could be an effective tool for biological control of this parasitic nematode in beef cattle.

Pochonia chlamydosporia fungal activity in a solid medium and its crude extract against eggs of Ascaridia galli.

The present study aimed to evaluate the ovicidal activity (type 3 effect) of VC1 and VC4 isolates of Pochonia chlamydosporia in a solid medium and the action of a crude extract of P. chlamydosporia against eggs of Ascaridia galli. To evaluate ovicidal activity in culture medium, 1000 A. galli eggs were plated on Petri dishes containing 2% water-agar with grown fungal isolates (VC1 or VC4) and without fungus (control group) and were examined at 1, 3 and 5 days post-inoculation (assay A). Then, to test the action of crude extracts of P. chlamydosporia (VC1 or VC4), 500 eggs of A. galli were plated on Petri dishes of 4.5 cm diameter with 5 ml of fungal filtrate from each tested isolate. The control group consisted of 500 eggs of A. galli with 10 ml of distilled water on each Petri dish (assay B). Fungal isolates were effective (P < 0.01) at destroying these eggs, showing a type 3 effect at the studied intervals. On the other hand, the crude extract of isolates (VC1 or VC4) reduced the number of A. galli eggs in the treated group compared with the control group by 64.1% and 56.5%, respectively. The results of the present study show that P. chlamydosporia is effective at destroying eggs of A. galli and could therefore be used in the biological control of nematodes.

Comparative analysis of destruction of the infective forms of Trichuris trichiura and Haemonchus contortus by nematophagous fungi Pochonia chlamydosporia; Duddingtonia flagrans and Monacrosporium thaumasium by scanning electron microscopy.

The present study aimed to demonstrate by scanning electron microscopy (SEM) the in vitro predatory activity of nematophagous fungi Pochonia chlamydosporia (VC1 and VC4 isolates) Duddingtonia flagrans (AC001 isolate) and Monacrosporium thaumasium (NF34a isolate) on eggs of Trichuristrichiura and infective larvae (L3) of Haemonchus contortus. The work was divided into two experimental tests (A and B). In tests A and B, the predatory activity of nematophagous fungi P. chlamydosporia, D. flagrans and M. thaumasium on eggs of T. trichiura and H. contortus L3 was observed. After 6h, in test A, isolates P. chlamydosporia (VC1 and VC4) had a role in destroying eggs of T.trichiura. For fungi D. flagrans and M. thaumasium the ovicidal activity on T. trichiura eggs was not observed. Test B showed that D. flagrans (AC001) and M. thaumasium (NF34a) were capable of predating H. contortus L3, but no predation by the fungus P. chlamydosporia was seen. These fungi can offer potential for the biological control of nematodes.

Activity in vitro of fungal conidia of Duddingtonia flagrans and Monacrosporium thaumasium on Haemonchus contortus infective larvae.

The objective of this work was to evaluate the predatory activity of the fungi Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34a) on Haemonchus contortus infective larvae (L3) in two experimental assays (A and B). In assay A, two treatments and one control were formed and kept for 7 days in Petri dishes with 2% water-agar. Each treatment consisted of 1000 H. contortus L3 and 1000 conidia of only one fungal isolate, and the control group consisted of 1000 L3, without fungus, with 10 repetitions per group. In assay B, 1000 conidia of one of the fungal isolates, AC001 or NF34a, were added to coprocultures made from 20 g of faeces collected from sheep naturally infected with H. contortus. At the end of the experiment, the Baermann method was used to count the non-predated larvae of all Petri dishes from treatment and control groups. In assay A, no difference was observed (P>0.05) between the groups treated with AC001 and NF34a fungi. A difference was observed (P < 0.05) between the treated and control groups. The L3 reduction percentages at the end of the experiment were 87.75 and 85.57%, respectively, for the fungal isolates compared to the control group. In assay B, the reduction percentages for conidia of these isolates were 85.82 and 87.32%, respectively. The results obtained show that D. flagrans (AC001) and M. thaumasium (NF34a) were effective in the in vitro control of sheep H. contortus L3 and could be used in the biological control of this nematode.

Optimizing protease production from an isolate of the nematophagous fungus Duddingtonia flagrans using response surface methodology and its larvicidal activity on horse cyathostomins.

Protease production from Duddingtonia flagrans (isolate AC001) was optimized and the larvicidal activity of the enzymatic extract was evaluated on infective horse cyathostomin larvae (L3). Duddingtonia flagrans was grown in liquid medium with eight different variables: glucose, casein, bibasic potassium phosphate (K2HPO4), magnesium sulphate (MgSO4), zinc sulphate (ZnSO4), ferrous sulphate (FeSO4), copper sulphate (CuSO4) and temperature. The Plackett-Burman analysis showed a significant influence of MgSO4, CuSO4 and casein (P < 0.05) on protease production by D. flagrans in liquid medium. Central composite design indicated that the highest proteolytic activity was 39.56 U/ml as a function of the concentrations of casein (18.409 g/l), MgSO4 (0.10 g/l) and CuSO4 (0.50 mg/l). A significant difference (P < 0.01) was found for the larval number between the treated and control groups at the end of the experiment. A reduction of 95.46% in the number of free-living larvae was found in the treated group compared with the control. The results of this study suggest that protease production by D. flagrans (AC001) in liquid medium was optimized by MgSO4, CuSO4 and casein, showing that the optimized enzymatic extract exerted larvicidal activity on cyathostomins and therefore may contribute to large-scale industrial production.

Ovicidal activity of different concentrations of Pochonia chlamydosporia chlamydospores on Taenia taeniaeformis eggs.

Three concentrations of chlamydospores of the nematophagous fungus Pochonia chlamydosporia (1000, 10,000 and 20,000 per Petri dish) were evaluated in vitro on Taenia taeniaeformis eggs. Chlamydospores at each concentration were cultured in two different media: 2% water-agar (2%WA) and 2% corn-meal-agar (2%CMA). Taenia taeniaeformis eggs were plated in each chlamydospore concentration in 2%WA and 2%CMA (treated groups) and without fungus (control group). Eggs were removed from each Petri dish at intervals of 7, 14 and 21 days and classified according to ovicidal activity (type 1, type 2 and type 3 effects). Plates containing 2%CMA showed the highest percentages for type 3 effect (81.3%) on the 21st day of observation. A difference (P < 0.01) between the media 2%WA and 2%CMA for type 1 effect was observed only at a concentration of 1000 chlamydospores on the 7th day. There were differences (P < 0.01) between 2%WA and 2%CMA on the 14th and 21st days, at the concentration of 20,000 chlamydospores, for type 1 and type 3 effects. Regression curves for type 3 effect in 2%WA and 2%CMA at the tested concentrations showed higher ovicidal activity with increasing chlamydospore concentrations. Results indicate that, at concentrations of 1000, 10,000 and 20,000 per Petri dish, chlamydospores of P. chlamydosporia effectively destroyed T. taeniaeformis eggs and can be considered a potential biological control agent for this cestode.