Introduction: Hydatidosis is a common disease of humans and livestock caused by Echinococcusgranulosus which is more common in Iran.It has 10 strains, G1to G10, which are different in morphology, epidemiology, treatment, control and also in their interfaces. The main objective of the present study is to investigate the morphological and molecular characteristics of Hydatid cysts in sheep and goats at theslaughterhouse of Rasht . Material and methods: In this study, 50 infected livers were transferred to the parasitology laboratory.After extraction of fluid cysts,morphological indices of rosetalprotoscolex hooks were measured by using an ophthalmic lens. Results: Based on the results of T-test for the samples of sheep and goats, it can be concluded that there is a significant difference between them in terms of some morphological characteristics.In the molecular part of this study, after DNA extraction, the PCR reaction was performed on the ITS1 gene. The PCR product was then digested by the Bsh1236I enzyme. The samples isolated from sheep and goats showed the strain G1 - G3. Discussion and conclusion: Iran is one of the most important breeders of sheep and goats in the world and can play an important role in the Echinococcus parasitic cycle. According to the current study, the highest strain found in sheep and goat is G1 strainwhich should be considered in control program.

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