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

Abstract

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.

Keywords: Echinococus granulosus; Iran; genotype; phenotype; wild sheep.

Fig. 1.

Khojir National Park located in the northeast of Tehran, Iran.

Fig. 2.

Agarose gel (1.2%), electrophoresis COX1, and ITS2 PCR products of E. granulosus derived from wild sheep isolates. Lane 1, ITS2 gene; lane 2, DNA size marker; lane 3, COX1 gene; lane 4, negative control.

Fig. 3.

Phylogenetic relationships of E. granulosus which was derived from wild sheep isolate in Iran based on ITS2 sequences in comparison with different isolates.

Fig. 4.

Phylogenetic relationships of E. granulosus which was derived from wild sheep isolates in Iran based on COX1 sequences in comparison with different isolates.