RESUMO
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.
Resumo O desenvolvimento rápido da resistência anti-helmíntica demonstrou a eficiência limitada no controle de endoparasitoses em animais, e promoveu a investigação em métodos de controles alternativos. O uso de produtos químicos no tratamento anti-helmíntico animal, em associação com fungos nematófagos utilizados para o controlo biológico, é uma estratégia que tem provado ser eficaz na redução da densidade da população de nematódeos em animais agrícolas. Este estudo teve como objetivo verificar a suscetibilidade in vitro dos fungos nematófagos Arthrobotrys oligospora, Duddingtonia flagrans e Paecilomyces lilacinus frente aos antiparasitários albendazol, tiabendazol, ivermectina, levamisol e closantel, usando a concentração inibitória mínima (MIC). Os MICs variaram entre 4,0 e 0,031 μg/mL para albendazol, tiabendazol e ivermectina, entre 0,937 e 0,117 μg/mL para o levamisol, e entre 0,625 e 0,034 μg/mL para closantel. Os resultados mostraram que todos os antiparasitários tiveram um efeito inibidor in vitro sobre os fungos nematófagos, o que poderia comprometer suas atividades como agentes de controle biológico. D. flagrans foi a espécie mais sensível a todas as drogas.
Assuntos
Animais , Fungos Mitospóricos/efeitos dos fármacos , Antiparasitários/farmacologia , Salicilanilidas/farmacologia , Ivermectina/farmacologia , Albendazol/farmacologia , Controle Biológico de Vetores , Levamisol/farmacologiaRESUMO
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.
Assuntos
Antiparasitários/farmacologia , Fungos Mitospóricos/efeitos dos fármacos , Albendazol/farmacologia , Animais , Ivermectina/farmacologia , Levamisol/farmacologia , Controle Biológico de Vetores , Salicilanilidas/farmacologiaRESUMO
In the winter of 2008, cattle on a farm in the province of Neuquen, Argentina died from subacute and chronic liver fluke disease despite four previous treatments with Triclabendazole (TCBZ). In the spring of 2009, a preliminary efficacy test revealed good performance using nitroxynil, whereas TCBZ efficacy was only 18% by egg counts of Fasciola eggs in the faeces. Resistance to Fasciola hepatica to TCBZ has never been reported in South America, so in January of 2010 a controlled trial was conducted to confirm and to define the degree of resistance in this herd. In a clinical trial, the fluke egg output was monitored on Days 14 and 21 and serum enzymes gamma-glutamyl transpeptidase (GGT) and glutamic-oxaloacetic transaminase (GOT) on Days 0 and 21 in 36 calves treated with TCBZ or with closantel. The results showed a reduction of 100% in fluke egg output at Days 14 and 21 for closantel. The mean epg in the TCBZ-treated groups did not decrease. Because of the fact that in this study TCBZ treatment in cattle had no effect, even at double the recommended dose, it is highly indicative that resistance of F. hepatica against TCBZ is present on this farm. The GGT and GOT levels decreased in the closantel-treated group as a result of the treatment at 21 days after dosing. To evaluate the importance of TCBZ resistance in F. hepatica in Argentina, a study on more farms from endemic areas is needed.
Assuntos
Anti-Helmínticos/farmacologia , Benzimidazóis/farmacologia , Doenças dos Bovinos/parasitologia , Fasciola hepatica/crescimento & desenvolvimento , Fasciolíase/veterinária , Hepatopatias/veterinária , Salicilanilidas/farmacologia , Animais , Anti-Helmínticos/uso terapêutico , Argentina , Aspartato Aminotransferases/sangue , Benzimidazóis/uso terapêutico , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/enzimologia , Resistência a Medicamentos , Fasciolíase/tratamento farmacológico , Fasciolíase/enzimologia , Fasciolíase/parasitologia , Fezes/parasitologia , Hepatopatias/tratamento farmacológico , Hepatopatias/enzimologia , Hepatopatias/parasitologia , Contagem de Ovos de Parasitas/veterinária , Salicilanilidas/uso terapêutico , Triclabendazol , gama-Glutamiltransferase/sangueRESUMO
The objective of this study was to determine the level of resistance of Haemonchus contortus and Trichostrongylus colubriformis in sheep to levamisole, albendazole, ivermectin, moxidectin, closantel and trichlorfon. The parasites were isolated from sheep naturally infected by gastrointestinal nematodes and were then kept in monospecifically-infected lambs for production of infective larvae (L3) of both species. Forty-two lambs, at three months of age, were simultaneously artificially infected with 4000 L3 of H. contortus and 4000 L3 of T. colubriformis. The animals were allocated into seven groups with six animals each that received one of the following treatments: Group 1--control, no treatment; Group 2--moxidectin (0.2mg/kg body weight (BW)); Group 3--closantel (10mg/kg BW); Group 4--trichlorfon (100mg/kg BW); Group 5--levamisole phosphate (4.7 mg/kg BW); Group 6--albendazole (5.0mg/kg BW); and Group 7--ivermectin (0.2mg/kg BW). Nematode fecal egg counts (FEC) were carried out on the day of treatment and again at 3, 7, 10 and 14 days post-treatment. On the same occasions, composite fecal cultures were prepared for each group for production of L3, which were identified into genus. The animals were sacrificed for worm counts at 14 days after treatment. The efficacy of each treatment was calculated from the arithmetic mean of the FEC or worm burden of the treated group, compared with the values of the control group. Only trichlorfon and moxidectin treatments resulted in a significant reduction of H. contortus recorded at necropsy (73% and 45% respectively). Moxidectin reduced T. colubriformis worm burdens by 82% and albendazole by 19%. All other anthelmintics resulted in no significant reduction in the numbers of worms found at necropsy. In conclusion, the isolates of H. contortus and T. colubriformis showed multiple resistance to all groups of anthelmintics tested. This is the first report, based on the controlled efficacy test, to show resistance of T. colubriformis to macrocyclic lactones in Brazil.
Assuntos
Anti-Helmínticos/farmacologia , Resistência a Múltiplos Medicamentos , Haemonchus/efeitos dos fármacos , Doenças dos Ovinos/tratamento farmacológico , Trichostrongylus/efeitos dos fármacos , Animais , Anti-Helmínticos/uso terapêutico , Brasil , Fezes/parasitologia , Hemoncose/tratamento farmacológico , Hemoncose/parasitologia , Hemoncose/veterinária , Ivermectina/farmacologia , Ivermectina/uso terapêutico , Levamisol/farmacologia , Levamisol/uso terapêutico , Contagem de Ovos de Parasitas , Salicilanilidas/farmacologia , Salicilanilidas/uso terapêutico , Ovinos , Doenças dos Ovinos/parasitologia , Carneiro Doméstico , Resultado do Tratamento , Tricostrongilose/tratamento farmacológico , Tricostrongilose/parasitologia , Tricostrongilose/veterináriaRESUMO
Seasonal population trends and effects of Oestrus ovis in naturally infected sheep were studied over 13 months, in the Western of the Pampeana region. At weaning, 140 growing lambs were randomly allocated to two groups: UG, untreated group and TG treated every 4 weeks with closantel (10 mg/kg). Successive Oestrus free tracer lambs (TL) by previous treatment (n = 65) were slaughtered after 20-30 exposition days for larval counts. Likewise, other group PL of 117 permanent untreated lambs was slaughtered from four to 17 months of age. Weighing and assessment of health signs of UG and TG and blood samples were monthly carried out. The prevalence of infection in permanent group varied from 33% to 100%. Mean number of larvae in PL was 6.1 with 3 L1, 1.4 L2 and 1.6 L3 during spring-summer and 17.9 with 16.9 L1, 0.5 L2 and 0.4 L3 during autumn-winter months. In PL the proportions of larvae in each of the different larval stages was similar during spring and summer, but a significant (P < 0.01) increase of L1 was detected during autumn and winter. The prevalence in tracer lambs was 100% during summer time and larvae were absent from 25-May to 25-October. Mean larval burdens of positive TL varied from 6.4 to one Oestrus and a significant peak (P < 0.05) of larvae was seen from December to March. Since March to November only L1 was recovered from TL. TG group showed a reduction in nasal discharge and in antibody ELISA levels, but no difference was observed in live weight gain between TG and UG. These results show a high prevalence during summer and that the perpetuation of Oestrus is ensured by an autumn period of arrested development and the over wintering larvae in the sheep heads.
Assuntos
Dípteros , Inseticidas/farmacologia , Miíase/veterinária , Doenças dos Ovinos/epidemiologia , Animais , Animais Recém-Nascidos/parasitologia , Anticorpos/sangue , Argentina/epidemiologia , Dípteros/efeitos dos fármacos , Dípteros/imunologia , Dípteros/patogenicidade , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Masculino , Miíase/tratamento farmacológico , Miíase/epidemiologia , Cavidade Nasal/parasitologia , Dinâmica Populacional , Prevalência , Distribuição Aleatória , Salicilanilidas/farmacologia , Estações do Ano , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologiaRESUMO
Se describe la primera comprobación de la actividad anticolinesterásica del closantel en caninos y bovinos. La determinación de los niveles de colinesterasa (ACE), fue realizada según la técnica de Ellman y la modificación que Brem Roux desarrollaron para la medición de la ACE en vacunos