en Infectious diseases and public health Infectious diseases and public health Original article Original article <b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Introduction</span></span></span></b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">: Trichostrongyloiasis is a prevalent infection in humans and some animals worldwide. Morphology is a reliable tool for identifying <i>Trichostrongylus</i> species. This study aimed to determine the prevalence of <i>Trichostrongylus</i> infection in livestock and compare the morphometric characteristics of the species in sheep and goats referred to Kashan Abattoir, Iran, in 2018. <b>Methods:</b> This cross-sectional study was performed on 130 goats and 154 sheep. The small intestine was collected from the slaughterhouse; the samples were opened and examined, and the genus and species of worms were identified based on morphological features reflected in diagnostic keys. Five morphometric indices, including body length and width, copulatory bursa width, shape length of the spicule, and gubernaculum length, were measured in 70 worm isolates. The data were analyzed using the ANOVA test in SPSS 18 software.<b> Results:</b> Of 284 livestock </span></span></span><span style="font-size:10.0pt"><span style="background:white"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">(130 goats and 154 sheep) examined</span></span></span></span><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">, 26 (9/15%) were infected with <i>Trichostrongylus.</i> The prevalence of infection in goats and sheep was 12.3% and 6.5%, respectively. The most frequent species were<i> Trichostrongylus colubriformis</i> (48.7%), followed by<i> Trichostrongylus vitrinus </i>(25.7%).</span></span></span> <i><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Trichostrongylus</span></span></span></i><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times=""> <i>capricula</i> and <i>Trichostrongylus</i> <i>probolurus</i> had an incidence of 12.8%. <i>T. probolurus</i> showed a higher length of spicule and gubernaculum, while <i>T. vitrinus</i> showed a wider copulatory bursa compared to the other species (<i>P</i> <0.001).<b> Conclusion:</b> The prevalence of <i>Trichostrongylus</i> infection in this region was remarkable. Morphometric and morphological methods are practical</span></span></span> <span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">tools in differentiating male <i>Trichostrongylus</i> species. However, in addition to morphometric studies, molecular methods are required to identify female worms, larvae, and eggs accurately.</span></span></span> Nematoda, Morphology, Sheep, Goats, Trichostrongylus 28 33 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-182-3&slc_lang=en&sid=1 Mohsen Arbabi arbabi4.mohsen@yahoo.com 0000-0001-8867-447X No Department of Medical Parasitology, Kashan University of Medical Sciences, Kashan, Iran Aimohammad Bakhshi bakhshiali74@gmail.com 0000-0002-1947-8333 No Department of Medical Parasitology, Kashan University of Medical Sciences, Kashan, Iran. Hossein Hooshyar hooshyar4@yahoo.com 0000-0002-9607-1182 Yes Department of Medical Parasitology, Kashan University of Medical Sciences, Kashan, Iran. Reza Ghasemikhah ghasemikhah@gmail.com 0000-0002-9677-7484 No Department of Medical Parasitology, Arak University of Medical Sciences, Arak, Iran Mahdi Delavari mdelavari1@gmail.com 0000-0002-1764-8108 No Department of Medical Parasitology, Kashan University of Medical Sciences, Kashan, Iran. Mojtaba Sehat mojtaba.sehat@gmail.com 0000-0001-7142-4829 No Department of Community Medicine, Kashan University of Medical Sciences, Kashan, Iran