Flukicide efficacy against Fasciola hepatica of Triclabendazole and Nitroxynil in cattle of the central valley of Chile / Avaliação da eficácia de triclabendazol e nitroxinil para o tratamento da infeção por Fasciola hepatica em bovinos do Vale Central do Chile

Abstract On a farm with permanent history of fasciolasis a study was performed aimed to know the efficacy of triclabendazole (TCBZ) and then to contrast with that of nitroxynil. Thirty-nine cattle naturally infected with Fasciola hepatica were randomly allocated into 4 experimental groups: Group 1 (control) was left untreated. Group 2 was treated with of 12 mg/kg body weight (bw) of TCBZ by oral route. Group 3 treated with 24 mg/kg bw TCBZ orally. Group 4 was treated with 10 mg/kg bw of nitroxynil subcutaneously. The anthelmintic efficacy was calculated as the percentage of reduction in faecal egg count (FEC) at 14 and 28 d post-treatment. Results indicated that there were no significant differences in the percentage of FEC reduction between control group and the groups treated with 12 or 24 mg/kg of TCBZ. On the contrary, the treatment with nitroxinyl significantly reduced the FEC and decreased the percentage of positive animals. In conclusion, Fasciola hepatica is reported for first time as resistant to TCBZ in Chile, which highlights the need of rotating drugs and assessing the efficacy of the administered drug in order to avoid the selection of resistant worms.

Resumo Em uma fazenda com histórico de fasciolose permanente, foi realizado um estudo com o objetivo de conhecer a eficácia do triclabendazol (TCBZ) e depois contrastar com o do nitroxinil. Trinta e nove bovinos naturalmente infectados com Fasciola hepatica foram distribuídos aleatoriamente em 4 grupos experimentais: Grupo 1 (controle), sem tratamento. O grupo 2 foi tratado com 12 mg/kg de peso vivo (PV) do TCBZ por via oral (VO). Grupo 3 tratado com 24 mg/kg de PV TCBZ por VO. O grupo 4 foi tratado com 10 mg /kg de PV Nitroxinil via subcutânea. A eficácia anti-helmíntica foi calculada comparando a percentagem de redução na contagem de ovos fecais (FEC) 14 e 28 dias pós tratamento. Não houve diferença significativa na porcentagem de redução FEC entre o grupo controle e os grupos tratados com 12 ou 24 mg/kg de TCBZ. Entretanto, o tratamento com nitroxinil reduziu significativamente o FEC e diminuiu a porcentagem de animais positivos. Em conclusão, a Fasciola hepatica é relatada pela primeira vez como resistente ao TCBZ no Chile, o que destaca a necessidade de realizar uma rotação em relação aos medicamentos anti-helmínticos e avaliar a eficácia do mesmo, a fim de evitar a seleção de vermes resistentes.

"Liver fluke": conceptos actuales sobre fascioliasis / Liver fluke: update on fascioliasis

Fascioliasis is a parasitic disease produced mainly by the fluke Fasciola hepatica. The human infection is mainly due to the accidental intake of metacercariae present in watercress and/or contaminated water. The human disease is uncommon in Chile, despite the high prevalence of animal infection, which affects almost the entire national territory and determines high economic and productive impacts. Human fascioliasis can manifest like acute or chronic phase of the disease (in Chile, the majority in chronic phase) and its identification requires a high index of suspicion, in individuals with abdominal pain, hepatomegaly and eosinophilia, where the epidemiological background of watercress ingestion is usually present. Diagnosis usually requires the integration of egg visualization in stools, serology and imaging studies. The treatment of choice with triclabendazole is usually highly effective and safe.

La fascioliasis es una enfermedad parasitaria producida principalmente por el trematodo Fasciola hepática. La infección en el hombre, quien es un huésped accidental, se debe principalmente a la ingesta de metacercarias presentes en berros y/o aguas contaminadas. La enfermedad en humanos es infrecuente en Chile, a pesar de la alta prevalencia de infección animal, que afecta a casi todo el territorio nacional y determina un alto impacto económico y productivo. La fascioliasis humana puede manifestarse en fase aguda o crónica (en Chile, la mayoría en fase crónica) y su identificación requiere un alto índice de sospecha, en individuos con dolor abdominal, hepatomegalia y eosinofilia, donde el antecedente epidemiológico de ingesta de berros suele estar presente. El diagnóstico, habitualmente requiere la integración de la visualización directa de huevos en las deposiciones, estudios de serología e imágenes. El tratamiento de elección con triclabendazol, habitualmente es altamente efectivo y seguro.

Study on glutathione S-tranferase [GST] inhibition assay by triclabendazole.1: Protoscoleces [Hydatid cyst; Echinococcus granulosus] and sheep liver tissue

Hydatid disease is a term used to refer infection with the methacestode of Echinococcus granulosus parasite in humans, and echinococcusis is restricted to infection with the adult stage in carnivores.Glutathione S-Transferase [GST] represents the major class of detoxification enzymes from helminth parasites such as Echinococcus protoscoleces [PSC] and it is candidate for chemotherapeutic and vaccine design. Therefore, GST of protoscoleces could be a target for evaluation of drug effect as triclabendazole in hydatid cyst. For this purpose, GST enzymes were purified from protoscoleces of hydatid cyst and sheep liver tissue by glutathione affinity chromatography using a wash-batch method and subsequently detected their SDS-PAGE pattern. Afterward, GST specific activity levels were assayed in the whole extract and purified solutions spectrophotometrically at 30 C with reduced glutathione [GSH] and 1-chloro-2, 4-dinitrobenzen [CDNB] substrate. Finally, GST inhibition assay was investigated in the solutions by powder and bolus of triclabendazole. GST fraction as a 26 kDa [MW] band was obtained on SDS-PAGE. The level of GST specific activity in purified solutions was detected 10.24 mmol/min/mg proteins for protoscoleces and 37.84 mmol/min/mg protein for liver tissue. Comparison of the effect of powder and bolus of triclabendazole in solutions revealed inhibition concentration [IC50] 8.71 and 11.16 mg/ml for protoscoleces GST and 8.65 and 9.70 mg/ml for liver tissue GSTs, respectively. These findings suggest the possibility of selective inhibition of protoscoleces. GSTs by triclabendazol in vitro and use of these results for understanding of its molecular effect in vivo