Abstract
Parasitic nematodes of ovine abomasum are of economic and hygienic importance throughout the world and Iran. This study was aimed to evaluate molecular identity and species diversity of parasitic nematodes in the abomasum of slaughtered sheep in Ilam, Iran. In this study, a total number of 240 of abomasa were randomly collected from the slaughtered sheep at industrial slaughterhouses in Ilam in all seasons between 2017 and 2018. The abomasum content and abomasal mucosa were removed and washed. The collected nematodes were morphologically identified. The genomic DNA was extracted and a 300 bp-fragment-length from internal transcribed spacer 2 ribosomal ribonucleic acid (ITS2-rRNA) gene was amplified. Overall prevalence was 66.70% (160/240). Five species of four genera of nematodes including Marshallagia marshalli (43.70%), Ostertagia circumcincta (15.50%), Parabronema skrjabini (5.00%), M. occidentalis (2.50%), and Haemonchus contortus (0.04%) were identified. Ostertagia circumcincta and H. contortus were found to be different in two nucleotides. There was no nucleotide difference between M. marshalli and M. occidentalis. This study revealed a significant prevalence of parasitic nematodes in sheep abomasum and species diversity of Trichostrongylid nematodes in the region.