[Genetic variation of Echinococcus granulosus isolates from Indian buffalo and Iranian sheep, cattle and camel]

ABSTRACT

India and Iran are an important endemic focus of cystic hydatid disease [CHD], where several species of intermediate host are commonly infected with Echinococcus granulosus. Strain characterization of E. granulosus is significant for the development of an effective control programme and to asses the infectivity. In present study, genetic variations in tapeworms causing cystic echinococcosis in the North of India and Iran were investigated and compared. Isolates of E. granulosus were collected from buffalo [India] and sheep, cattle, and camel isolates from Iran. PCR linked RFLP approach of ITS1 region of rDNA. Repeat was used in the present study to characterize buffalo isolates from sheep, cattle and camel. 17 pooled samples of protoscoleces from various animals were used for DNA extraction and PCR-RFLP analysis respectively. The PCR products of each isolates were digested separately with 5 restrictive endonucleases enzymes [AluI, HhaI, MspI, TaqI and EcoRI]. Based on the PCR-ITS1 method, the buffalo [liver and lungs] isolates have shown different genotypes and the sheep, cattle and camel isolates appeared to have the same genotype. The RFLP patterns of buffalo lung isolates differed from liver isolates with Taq1 and Hha1, however, showed a similarity with Msp1, EcoR1 and Alu1. Furthermore, differences in numbers and sizes of bands were also observed between buffalo, sheep and camel isolates with Taq1 and Msp1. The sheep and camel isolates differ in the number and sizes of fragments with Msp1 and Taq1. The buffalo lung isolate were quite different from other isolates, with the liver isolate showing a similarity with the sheep isolate. RFLP pattern of isolates from sheep and camel origin was identical, along with the same patterns. Moreover, the existence of buffalo strains [G1 and G3] and sheep strain [G1] were confirmed and our results support the previous studies in Northern India and Iran. These results are relevant for the possibility of transmission of G1 and G3 genotype, between livestock, animals and humans. It can be speculated that buffalo lung isolates represent G3 genotype and liver isolate as G1 genotype. Further, the existence of sheep [G1] strain was also confirmed in Iran by this study. However, more molecular studies, particularly, mitochondrial gene and amino acid sequencing are required, which can provide valuable data for a better understanding of the differences between different cysts localization