Rapid Detection and Identification of Fasciola spp. and Dicrocoelium spp. Isolated from the Ruminant Livestock of Northwest Iran Using High-Resolution Melting Analysis (HRM)

The liver flukes of the Fasciola species and Dicrocoelium spp. are recognised as parasites of domestic and wild herbivores. Both species of F. hepatica and F. gigantica as well as D. dendriticum are distributed in Iran. The present study aimed to identify Fasciola spp. and Dicrocoelium spp. using mitochondrial Cox1 (cytochrome c oxidase I) gene by HRM method.

Totally, thirty infected liver specimens were collected from the sheep (n:23) and cattle (n:7) at the abattoirs of Qazvin Province, northwest Iran in 2022. DNA extraction and PCR amplification of Cox1 gene were conducted by HRM technique. DnaSP v.5.0 was used for compression of diversity indices of ribosomal 28S rDNA and mitochondrial Cox1 markers of Dicrocoelium spp. The taxonomic status of Dicrocoelium spp. was performed by sequencing and phylogenetic analysis.

Overall, 26 and 4 isolates were identified as F. hepatica and F. gigantica, respectively. D. dendriticum was the sole infecting species of Dicrocoelium revealed by HRM analysis. Genomic analysis showed a moderate (28S rDNA genes: 0.600±0.215) to high (Cox1: 0.733±0.155) haplotype diversity for D. dendriticum.

The parasite-dependent mitochondrial gene (Cox1) could identify a higher genetic diversity of D. dendriticum compared to nuclear 28S rDNA gene. HRM technique in the present study found to be a reliable technique for identification and genetic diversity of liver flukes but more comprehensive and in-depth studies in different parts of the country are needed.