Genotype and Phenotype of Echinococcus granulosus Derived from Wild Sheep (Ovis orientalis) in Iran

The aim of the present study is to determine the characteristics of genotype and phenotype of Echinococcus granulosus derived from wild sheep and to compare them with the strains of E. granulosus sensu stricto (sheep-dog) and E. granulosus camel strain (camel-dog) in Iran. In Khojir National Park, near Tehran, Iran, a fertile hydatid cyst was recently found in the liver of a dead wild sheep (Ovis orientalis). The number of protoscolices (n=6,000) proved enough for an experimental infection in a dog. The characteristics of large and small hooks of metacestode were statistically determined as the sensu stricto strain but not the camel strain (P=0.5). To determine E. granulosus genotype, 20 adult worms of this type were collected from the infected dog. The second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA (rDNA) and cytochrome c oxidase 1 subunit (COX1) of the mitochondrial DNA were amplified from individual adult worm by PCR. Subsequently, the PCR product was sequenced by Sanger method. The lengths of ITS2 and COX1 sequences were 378 and 857 bp, respectively, for all the sequenced samples. The amplified DNA sequences from both ribosomal and mitochondrial genes were highly similar (99% and 98%, respectively) to that of the ovine strain in the GenBank database. The results of the present study indicate that the morpho-molecular features and characteristics of E. granulosus in the Iranian wild sheep are the same as those of the sheep-dog E. granulosus sensu stricto strain.

Aportes morfológicos y morfométricos sobre Echinococcus granulosus para vacuna ovina EG95 / Morphological and morphometric contributions on Echinococcus granulosus for EG95 sheep vaccine

Se describe el estadío adulto de la cepa de Echinococus granulosus, utilizada en la validación de la Vacuna Ovina EG95 en el marco del Programa de Control de Hidatidosis (Provincia de Chubut, Argentina), con el propósito de medir la efectividad de la Vacuna Ovina EG95, elaborada por el Laboratorio de Parasitología Molecular de la Universidad de Melbourne de Australia. Se estudiaron treinta ejemplares adultos de E. granulosus (conservados en formol al 10%) cuyo tamaño osciló entre 1,6 y 5,1 mm de largo. Los resultados mostraron que, además de su escólex, el parásito adulto presenta entre 3 y 5 proglótidos. En los ejemplares observados la proglótida grávida siempre era la última, independientemente de la cantidad de proglótidas presentes. El promedio de huevos de cada proglótido grávida fue 525 por parásito (rango de 405-808).

The adult stage of the Echinococus granulosus strain used in Sheep Vaccine EG95 validation within the framework of the Hydatidosis Control Program (Chubut Province, Argentina) is described in this work in order to measure the effectiveness of this vaccine developed by the Molecular Parasitology Laboratory of Melbourne University, Australia. Thirty adult specimens of E. granulosus (in 10% formalin) were studied. The size of these specimens ranged from 1.6 to 5.1 mm long. The results showed that, in addition to its scolex, the adult parasite presents 3 and 5 proglottids. In the specimens observed, the gravid proglottid was always the last one, regardless of the number of proglottids present. The average number of eggs of each gravid proglottid was 525 per parasite (range 405- 808).