Molecular Characterization of Mitochondrial Genome From Trichostrongylus Species (Nematoda: Trichostrongylidae) in Northern Iran

Abstract

Background: The members of Trichostrongylus spp. are gastrointestinal nematodes of ruminants with worldwide distribution. The nematodes are considered as major health challenges especially in endemic regions of Iran. Several species of the parasite are reported from humans and animals in the country. Frequently, molecular analyses for identification of different species focus on nuclear regions and there is lack of information regarding the mitochondrial genes of Trichostrongylus spp. Therefore, the aim of the present study was to identify Trichostrongylus species by molecular analysis of mitochondrial gene in Guilan province, northern Iran.Methods: The nematodes were collected from the abomasum contents of sheep, goats and cattle. Morphological survey was performed for initial screening. Total DNA was extracted, and the partial region of cytochrome c oxidase subunit I (Cox1) gene was amplified and sequenced. Genetic diversity was calculated and phylogenetic analysis of the nucleotide sequence data was conducted.Results: Three species of Trichostrongylus including T. colubriformis, T. vitrines and T. axei were identified by morphological characterizations. The genetic divergence within the species in the present study was observed for T. axei (0-2.5%), T. colubriformis (0.77%) and T. vitrinus (0%). The mean inter-species difference between the Trichostrongylus species obtained in this study was 14.4- 15.4%.Conclusions: The Cox1 sequences of members of the Trichostrongylus spp. are highly variable and this could be used as a valuable measure for achieving a proper assessment of biodiversity. Sequence data generation from additional species of Trichostrongylus will be needed to reconstruct the phylogenetic relationships of this genus of nematodes.