en Infectious diseases and public health Infectious diseases and public health Original article Original article <p dir="ltr"><strong>Introduction: </strong>To determine an indicator for Triclabendazole (TCBZ) efficacy, Alanine aminotransferase (ALT) activity in <em>Fasciola hepatica </em>(Iranian isolate) parasite in presence and absence of TCBZ was evaluated by an in vitro cultivation method. Also, ALT enzyme activity between none and parasitized-infected sheep liver tissues was assessed. <strong>Method: </strong>&nbsp;The sheep livers were collected and transferred immediately to the Department of Parasitology<em>. </em>Adult living parasites were recovered, washed and divided into two groups, treatment and control groups with 10 parasites in each. We added 15 &mu;g TCBZ to the treatment group; then incubated both groups for 4 h at 37&ordm;C. The parasites, infected and parasite free liver tissues were ground and homogenized by a Mortar and pestle, centrifuged, and supernatants were recovered. Protein concentration and ALT enzyme activity were measured in the supenatants. <strong>Results:</strong> The results of ALT enzyme activity assay showed 0.03 U/ml/mg protein for treated <em>F. hepatica </em>and 0.01 U/ml/mg protein for untreated samples, the mean values of difference was not significant (<em>p</em>>0.05). The difference between ALT activity in none and parasitized-infected liver was not significant (<em>p</em>>0.05). However, two-sample T-test analysis showed higher ALT activity in treated and untreated parasite in comparison with none and parasitized-infected liver specimens (<em>p</em><0.05). In addition to ALT protein band for parasite and liver tissue, Cathepsin enzyme (proteases) was detected for parasite by SDS-PAGE analysis. <strong>Conclusion:</strong> ALT activity cannot be considered as a useful marker for TCBZ efficacy in <em>F. hepatica</em> treatment. However, ALT enzyme showed comparable activities in parasite and its host liver tissue.</p> Alanine Aminotransferase, Fasciola hepatica, Egaten®, Triclabendazole, Liver 1 5 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-80-1&slc_lang=en&sid=1 Ali Farahnak farahnak@tums.ac.ir Yes Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Fariba Amni hiva.hamidi63@yahoo.com No Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Taghi Golmohammadi Golmoham@tums.ac.ir No Department of Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Eshraghian eshraghianmr@tums.ac.ir No Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mohammad Bagher Molaei Rad mb-molaeirad@farabi.tums.ac.ir No Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran