Genetic characterization of the causative agent of besnoitiosis in goats in Iran on the basis of internal transcribed spacer rDNA and its comparison with Besnoitia species of other hosts

摘要

This study was conducted to identify genetic characteristics of Besnoitia spp. isolated from goat in Iran. Molecular analysis of two portions of nuclear ribosomal DNA (ITS1 and ITS2) was used for the genetic characterization of the Besnoitia species. Comparison of the sequencing data of the Iranian Besnoitia samples obtained in the present study (GenBank accession number HM008988) with those previously reported for other Besnoitia spp. in the GenBank database revealed a particularly close relationship between the present goat Besnoitia samples and the Besnoitia samples from the cattle, caribou, and equids (Besnoitia besnoiti, Besnoitia tarandi, and Besnoitia bennetti). This is the first use of a genetic approach to interrogate the identity of the species of Besnoitia infecting Iranian goats. Also, the results of the present study showed the occurrence of a similar sequence polymorphism for ITS1 and ITS2 in all Iranian isolates, which exhibit 100% identity in these ribosomal sequences, to those of B. besnoiti previously reported from Israel. Although the ITS1 sequence of Iranian goat isolates is identical to European cow isolates, the ITS2 sequences derived from present Besnoitia genotype differed in one nucleotide position compared with other European B. besnoiti. Further studies should be employed based on this molecular data to identify the natural definitive host in order to complete the life cycle of this distinct genotype of parasite.