Navegando por Autor "Silva, André Ricardo"

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Biological control of cyathostomin (Nematoda: Cyathostominae) with nematophagous fungus Monacrosporium thaumasium in tropical southeastern Brazil
(Veterinary Parasitology, 2010-09-30) Tavela, Alexandre de Oliveira; Araújo, Jackson Victor; Braga, Fábio Ribeiro; Silva, André Ricardo; Carvalho, Rogério Oliva; Araujo, Juliana Milani; Ferreira, Sebastião Rodrigo; Carvalho, Giovanni Ribeiro
Horses are hosts to a wide variety of helminthes; the most important are the cyathostomin, or small strongyles. The viability of a fungal formulation (pellets) using the nematode- trapping fungus Monacrosporium thaumasium was assessed in biological control of horse cyathostomin. Two groups (fungus-treated and control) consisted of six mares in each group, crossbred (ages of 2.5 and 3.5 years), were placed in pastures of Cynodon sp. naturally infected with horse cyathostomin larvae. In the treated group, each animal received 1 g/10 kg body weight (0.2 g/10 kg live weight of fungus) of pellets of sodium alginate matrix containing the fungus M. thaumasium orally, twice a week for 6 months. In the control group, animals received (1 g/10 kg body weight) of pellets without fungus. The egg count per gram of feces showed difference (p < 0.01) in the animals treated with the fungus in relation to the control animals during all months of the experiment. The EPG percent- age decrease were 87.5%, 89.7%, 68.3%, 58.7%, 52.5% and 35.2% during June, July, August, September, October and November, respectively. In faecal cultures, there was difference (p < 0.05) among animals treated with fungus was found in relation to the control animals during all the experiment month, with percentage reduction of 67.5%, 61.4% and 31.8% in September, October and November, respectively. Difference (p < 0.01) was observed in the recovery of infective larvae from pastures that were collected up to 20 cm from the dung pats in pastures in the group treated with the fungus in relation to the control group with a reduction of 60.9% and between 0–20 and 0–40 cm from the faecal pat reduction (p < 0.01) was about 56% in the group treated with the fungus M. thaumasium in relation to the con- trol group pasture. There was no difference (p > 0.05) between the average weight gains in both animal groups. The treatment of horses with pellets containing the nematophagous fungus M. thaumasium can be effective in controlling cyathostomin in the tropical region of southeastern Brazil.
Biological control of horse cyathostomin (Nematoda: Cyathostominae) using the nematophagous fungus Duddingtonia flagrans in tropical southeastern Brazil
(Veterinary Parasitology, 2009-05-05) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Silva, André Ricardo; Araujo, Juliana Milani; Carvalho, Rogério Oliva; Tavela, Alexandre Oliveira; Campos, Artur Kanadani; Carvalho, Giovanni Ribeiro
The viability of a fungal formulation using the nematode-trapping fungus Duddingtonia flagrans was assessed for the biological control of horse cyathostomin. Two groups (fungus-treated and control without fungus treatment), consisting of eight crossbred mares (3–18 years of age) were fed on Cynodon sp. pasture naturally infected with equine cyathostome larvae. Each animal of the treated group received oral doses of sodium alginate mycelial pellets (1 g/(10 kg live weight week)), during 6 months. Significant reduction (p < 0.01) in the number of eggs per gram of feces and coprocultures was found for animals of the fungus-treated group compared with the control group. There was difference (p < 0.01) of 78.5% reduction in herbage samples collected up to (0–20 cm) between the fungus-treated group and the control group, during the experimental period (May–October). Difference of 82.5% (p < 0.01) was found between the fungus-treated group and the control group in the sampling distance (20–40 cm) from fecal pats. During the last 3 months of the experimental period (August, September and October), fungus-treated mares had significant weight gain (p < 0.01) compared with the control group, an increment of 38 kg. The treatment with sodium alginate pellets containing the nematode-trapping fungus D. flagrans reduced cyathostomin in tropical southeastern Brazil and could be an effective tool for biological control of this parasitic nematode in horses.
Efeito do fungo Paecilomyces lilacinus sobre ovos de Taenia saginata
(Revista da Sociedade Brasileira de Medicina Tropical, 2008-10-09) Braga, Fabio Ribeiro; Araújo, Jackson Victor de; Araujo, Juliana Milani; Carvalho, Rogério Oliva; Silva, André Ricardo
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 action of a crude enzymatic extract of the fungus Pochonia chlamydosporia against cyathostomin eggs
(Veterinary Parasitology, 2010-05-11) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Carvalho, Rogério Oliva; Silva, André Ricardo; Araujo, Juliana Milani; Soares, Filippe E. Feitas; Geniêr, Hugo L. André; Ferreira, Sebastião Rodrigo; Queiroz, José Humberto
The aims of this study were to test the action of the fungal extract of Pochonia chlamydosporia (VC4) on the hatching of cyathostomin eggs plated in Petri dishes containing 2% water-agar (2% WA) and its enzymatic activity in fecal cultures, in two experimental assays (A and B). The fungus P. chlamydosporia (VC4) was cultured in Erlenmeyer flasks (250 ml) containing 50 ml of liquid minimal medium supplemented with 0.2% gelatin for production of the crude enzymatic extract. Approximately 1 kg of fresh feces was collected directly from the rectum of crossbred horses naturally infected with cyathostomins. The fecal material was used to obtain eggs and prepare fecal cultures. For assay A, one thousand eggs were plated on 4.5 cm diameter Petri dishes together with 5 ml of VC4 fungal filtrate and incubated at 26 °C in the dark for 24 h. The control group consisted of 1000 eggs in Petri dishes containing 10 ml of distilled water, which were incubated under the same conditions. After 24 h, the total number of cyathostomin larvae present in each plate of the treated and control groups was counted. For assay B, about 20 g of feces were added with 10 ml of fungal extract of P. chlamydosporia (VC4) and incubated at 26 °C for 8 days. Third stage larvae (L3) were recovered at the end of this period. Significant difference (p < 0.01) was found for the number of larvae between the treated group and the control at end of assay A. A 72.8% reduction in the hatching of cyathostomin eggs was found in the plates of the treated group compared with the control group. At the end of 8 days, the fungal extract of P. chlamydosporia (VC4), in assay B, was effective in reducing the number of L3 cyathostomins in the treated group by 67.0% compared with the control group. Significant difference (p < 0.01) was found between the means of L3 recovered from the treated group and the control group. The results of this work showed that crude enzymatic extract of P. chlamydosporia (VC4) was effective in reducing hatching of cyathostomin eggs and therefore could be used as a biological control agent of this nematode.
Perfil da implantação de cisticercos de Taenia saginata em sítios musculares não usuais e sua importância para a Saúde Pública
(Pesquisa Veterinária Brasileira, 2018-01) Peixoto, Rafaella Paola M. Guimarães; Pinto, Paulo Sérgio A.; Silva, Letícia F.; Acevedo-Nieto, Emílio C.; Silva, André Ricardo
A cisticercose bovina é uma zoonose de distribuição mundial. No Brasil, o controle é realizado através do diagnóstico anatomopatológico durante a inspeção post-mortem nos matadouros. Objetivou-se neste estudo determinar a localização de cisticercos nos tecidos rotineiramente inspecionados e sobretudo nos tecidos não rotineiramente inspecionados, verificando a viabilidade dos cisticercos em bovinos infectados de forma experimental (grupo 1) e natural (grupo 2) com ovos de Taenia saginata. Em ambos os grupos foram analisados os tecidos rotineiramente inspecionados nas linhas de inspeção, de acordo com os padrões estabelecidos na legislação do Brasil. Adicionalmente, no grupo 1 foram selecionadas outras regiões anatômicas, representadas por quatro cortes comerciais (acém, alcatra, contrafilé, paleta), além do fígado, esôfago, diafragma e pilares. Com relação à frequência dos cisticercos no grupo 1, nos cortes comerciais, foram encontrados 8,2% de cisticercos no acém, 6,6% na paleta, 6,2% no contrafilé e 5,8% na alcatra. Outros tecidos não rotineiramente inspecionados para a exclusiva pesquisa por cisticercos que apresentaram lesões foram o diafragma, fígado e o esôfago, com 2,7%, 12,0% e 1,2% respectivamente. No grupo 1, os sítios rotineiramente inspecionados predominantes foram o coração (37,7%), músculos mastigatórios (17,1%) e língua (2,3%). No grupo 2 foram encontrados 61,8% dos cisticercos totais no coração, seguido dos músculos mastigatórios (38,2%) e fígado (10,2%). Com relação à viabilidade dos cisticercos no grupo 1, os viáveis predominaram na alcatra (80,0%), diafragma (71,4%) e esôfago (66,7%), já os cisticercos inviáveis predominaram nos músculos mastigatórios (77,3%), coração (76,3%), fígado (71,0%) e língua (50%). No grupo 2, o fígado apresentou 87,5% de cisticercos inviáveis, seguidos da língua (66,7%) e coração (63,2%), e nos tecidos mastigatórios foram encontrados 68,3% de cisticercos viáveis (68,3%). O alto percentual de cisticercos viáveis encontrado nos cortes comerciais, inclusive nos bovinos naturalmente infectados, representa um alerta para a Saúde Pública, pois, no Brasil, são frequentemente consumidos sem sofrer o devido tratamento térmico para inativação do cisticerco, aumentando consideravelmente a chance de infecção por teniose. Os resultados revelaram amplo perfil da manifestação anatomopatológica da cisticercose em diferentes tecidos de bovinos experimentalmente e naturalmente infectados, considerando-se tecidos musculares rotineiramente inspecionados ou não. Assim, o aprimoramento da inspeção sanitária das carcaças bovinas pode incrementar o controle do complexo teniose-cisticercose, diminuindo os riscos para a saúde pública.
Viability of the nematophagous fungus Pochonia chlamydosporia after passage through the gastrointestinal tract of horses
(Veterinary Parasitology, 2009-11-24) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Silva, André Ricardo; Carvalho, Rogério Oliva; Araujo, Juliana Milani; Ferreira, Sebastião Rodrigo; Carvalho, Giovanni Ribeiro
The predatory capacity of the nematophagous fungus Pochonia chlamydosporia (isolate VC4) embedded in sodium alginate pellets after passage through the gastrointestinal tract of horses was assessed in vitro against Oxyuris equi eggs. Twelve previously dewormed crossbred mares, average weight of 362.5 kg (±21) were used in the experiment. Each animal of the treated group received an oral dose (100 g) of sodium alginate pellets containing P. chlamydosporia mycelial mass. The control group received pellets without fungus. Faecal samples from fungus-treated and control groups were collected at intervals of 8, 12, 24, 36, 48 and 72 h after pellet administration and placed in Petri dishes containing 2% water-agar. One thousand eggs of O. equi were plated in Petri dishes of both treated and control groups, with six replicates, and incubated in oven, 25 °C, in the dark, for 30 days. At the end of the experiment, one hundred eggs were removed from each Petri dish and classified according to the following parameters: type 1, physiological and biochemical effect without morphological damage to eggshell, with hyphae adhered to the shell; type 2, lytic effect with morphological change in the eggshell and embryo without hyphal penetration, and type 3, lytic effect with morphological change in the eggshell and embryo, with hyphal penetration and internal egg colonization. Chlamydospore production was observed in Petri dishes of the treated group. The isolate VC4 remained viable after passing through the gastrointestinal tract of horses and maintained the ovicidal activity against O. equi eggs when compared with the control group (p < 0.01) after each collection interval: 29.1% (8 h), 28.2% (12 h), 31.1% (24 h), 27.4% (36 h), 30.9% (48 h) and 28.4% (72 h). The results suggest that P. chlamydosporia could be used as an effective biological control agent of O. equi eggs in natural conditions.