Mitochondrial nad5 gene-based genetic diversity analysis of Echinococcus granulosus sensu lato hydatid cysts in small ruminants of north India.

BACKGROUND

Cystic echinococcosis, a neglected parasitic cyclo-zoonosis is endemic in the Indian subcontinent. The etiological agent for this potentially fatal disease is a cryptic species complex, Echinococcus granulosus sensu lato (s. l.). The present study aimed at evaluating the role of small ruminants in circulating various E. granulosus s. l. genotypes in north India.

METHODS AND

RESULTS

The cladistics, haplotype network and genetic structure analyses were performed on the E. granulosus s. l. isolates collected from the slaughtered small ruminants (n = 1049) of north India (Chandigarh, Himachal Pradesh and Haryana) along with GenBank-archived E. granulosus s. l. sequences (n = 20) of ruminant origin from the Indian subcontinent by targeting the mitochondrial nad5 gene. The NCBI BLASTn analysis revealed the presence of zoonotic genotypes G1, G3 (E. granulosus sensu stricto), G5 (E. ortleppi), and G6 (E. canadensis). Haplotype network analysis exhibited the presence of 14 haplotypes, where the haplotypes corresponding to E. granulosus sensu stricto (s. s.) species (genotypes G1 and G3) were arranged in a stellate conformation. High haplotype (0.837 ± 0.059, 0.836 ± 0.068 and 0.894 ± 0.078) and low nucleotide (0.0249 ± 0.0104, 0.0369 ± 0.0142 and 0.0036 ± 0.0008) diversities were recorded for the overall data set, as well as Indian and Pakistani E. granulosus s. l. populations, respectively.

CONCLUSION

Based on the mitochondrial nad5 gene, the present study provided comprehensive insights into the cladistics and population structure of E. granulosus s. l. genotypes circulating in north India and highlighted the role of sheep/goat-dog cycle in the circulation of the zoonotic genotypes.