RESUMO
The main goal of the current work was to develop and validate an in vitro fluke egg hatch test, as a method for the detection of albendazole (ABZ) resistance in the liver fluke, Fasciola hepatica. Fluke eggs (200/ml, n= 5) from six different isolates were used in the current experimental work. They were obtained from different geographical locations and named Cullompton (UK), CEDIVE (Chascomus, Argentina), INTA-Bariloche (Bariloche, Argentina), Rubino (Uruguay), Cajamarca (Perú) and Río Chico (Catamarca, Argentina). The fluke eggs were incubated (25 °C) for a 12-h period in the presence of either ABZ or its sulphoxide metabolite (ABZ.SO) (5, 0.5 or 0.05 nmol/ml). Untreated eggs were incubated as a control. Incubated eggs (with or without drug present) were kept in darkness at 25 °C for 15 days. Afterwards, the trematode eggs were exposed to daylight over a 2-h period. Hatched and unhatched eggs were evaluated using an optical microscope, and the ovicidal activity was assessed for each fluke isolate. A very low ovicidal activity ( ≤ 13.4%) was observed in the ABZ-resistant CEDIVE isolate for both ABZ and ABZ.SO. Conversely, in the INTA-Bariloche and Río Chico isolates, which are suspected to be susceptible to ABZ, ovicidal activities ≥ 70.3% were observed after incubation with ABZ at the lowest concentration tested (0.05 nmol/ml). This finding correlates with that previously described for the ABZ-susceptible Cullompton. Finally, the Cajamarca and Rubino isolates behaved as ABZ resistant, since no ovicidal activity was observed after eggs were incubated with ABZ at 0.5 nmol/ml. Considering the specific results obtained for each isolate under assessment, the egg hatch test described here may be a suitable method for detection of ABZ resistance in F. hepatica.
Assuntos
Albendazol/farmacologia , Anti-Helmínticos/farmacologia , Resistência a Medicamentos , Fasciola hepatica/efeitos dos fármacos , Zigoto/efeitos dos fármacos , Animais , Fasciola hepatica/fisiologia , Testes de Sensibilidade Parasitária/métodos , Coelhos , América do Sul , Temperatura , Fatores de Tempo , Reino Unido , Zigoto/fisiologiaRESUMO
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
Brucellosis in sheep, caused by Brucella ovis, is primarily a chronic infectious disease of rams with epididymitis as its most characteristic lesion. Six hundred rams from an infected farm were clinically and serologically examined once a year, over a 3-year period. An increase from 2.1% to 6.3% in the prevalence of animals serologically positive to B. ovis occurred over the 3 years. However, the prevalence of rams with lesions in the reproductive tract declined from 14.2% to 6.5% in the third year following one year of strict culling of clinically affected and rams that were serologically positive for B. ovis. Clinical lesions found in the 179 affected rams fell into two main categories: rams with epididymitis and rams with affected lymph nodes. These results suggest that the prevalence of the disease relates mainly to the sexual activity of the animal and not to age in itself. A single cull based on the results of clinical examination and serological test results was unable to decrease the prevalence of B. ovis in an extensive Corriedale sheep flock.
Assuntos
Brucelose/veterinária , Doenças dos Ovinos/epidemiologia , Fatores Etários , Animais , Argentina/epidemiologia , Brucelose/epidemiologia , Brucelose/patologia , Epididimite/epidemiologia , Epididimite/patologia , Epididimite/veterinária , Linfonodos/patologia , Masculino , Prevalência , Ovinos , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/patologia , Fatores de TempoRESUMO
Forty-four of a flock of 117 angora goats in the Rio Negro province of Argentina died within four days. Most of the animals died shortly after the onset of clinical signs, but in a few the clinical course lasted for several days. Post mortem the small and large intestines were filled with watery contents, blood and fibrin clots, and there were numerous ulcers on the mucosa. Small areas of malacia were observed histologically in the brain. Clostridium perfringens type D in pure culture was isolated from the kidneys and gut contents of the affected animals. Epsilon toxin was identified by the mouse seroneutralisation test in the supernatant solution from cultures of these isolates and in the intestinal contents of the affected animals. Heavy infestations with coccidia, nutritional and environmental stress, and an anthelmintic overdose were possible predisposing factors for the outbreak.
Assuntos
Clostridium perfringens/isolamento & purificação , Surtos de Doenças/veterinária , Enterotoxemia/microbiologia , Doenças das Cabras/microbiologia , Animais , Argentina/epidemiologia , Toxinas Bacterianas/análise , Enterotoxemia/complicações , Enterotoxemia/epidemiologia , Enterotoxemia/patologia , Feminino , Doenças das Cabras/epidemiologia , Doenças das Cabras/patologia , Cabras , MasculinoRESUMO
'Mal seco' is a grass sickness-like syndrome of horses in Argentina. A histopathological study was made of the coeliaco-mesenteric ganglia of four horses with 'mal seco' and of four horses that died from other causes. The severity and extent of the lesions found in the horses with 'mal seco' was greatest in the two with the shortest clinical course. Degenerative changes consisted mainly in the loss of Nissl substance, cytoplasmic vacuoles, neuronophagia, intercellular and intracytoplasmic eosinophilic bodies, and pyknotic and eccentric nuclei. The coeliaco-mesenteric ganglia of the control horses had no histological lesions. The histological lesions in the horses with 'mal seco' were very similar to those described in the coeliaco-mesenteric ganglia of horses with grass sickness in Europe and it is suggested that 'mal seco' and grass sickness may be the same disease.