Introduction: Ostertagia (Teladorsagia) species can cause significant economic losses to animal husbandry by causing structural and functional changes in the abomasum, reducing the production and mortality of small ruminants. This study aimed to determine the morphometric and phylogenetic characteristics of species isolated from goats in the west and southwest of Iran. Materials & methods: During 2023, a total of 315 slaughtered goats were sampled in Western (West Azerbaijan Province) (n:200) and Southwest (Khuzestan) (n:115) slaughterhouses. A total, of 320 Ostertagia (210 from the west) and (110 from the southwest) from the abomasum of slaughtered goats were identified and separated from other nematodes using a stereomicroscope. According to morphometric parameters, 180 Ostertagia (Teladorsagia) isolates of male (140) and female (40) worms, which had clear indicators, were prepared and determined by standard micrometric methods. Finally, 18 Ostertagia isolates (12 males and 6 females) from two regions that had the greatest phenotypic differences were sequenced using the ITS2 gene and molecular methods. Results: The morphological and molecular results showed that the isolates included Teladorsagia circumcincta, Teladorsagia trifurcata and Marshallagia occidentalis. In comparison, some characteristics of male worms were significantly different between the three species of each region and also between the two regions (P<0.001). There was a significant difference in the ratio of esophagus to body length only in Ostertagia occidentalis species in both regions (P<0.05). Although, there was no significant difference in Teladorsagia circumcincta and T. trifurcata female worms (P<0.05). But there was a significant difference in some indicators (the length of the vulva flap, the distance of the flap from the beginning of the ovijector, and the distance of it from the end of the ovijector). Conclusion: Phylogenetic analysis and ITS2 sequences showed the presence of four genotypes of Teladorsagia circumcincta, three genotypes of Teladorsagia trifurcata and two genotypes of Marshallagia occidentalis. The results of this study did not show a direct relationship between the genotypes of different isolates and the characteristics of their phenotypic changes. The relationship between phenotypic and genotypic changes requires more additional studies. Due to the regional infection of the three identified species of Ostertagia, it is necessary to manage their control program.
Alborzi A, Noorani Koliji O, Razi jalali M H, Tabandeh M R, Pourmahdi Borujeni M. Morphometric and phylogenetic study of Ostertagia (Teladorsagia) isolates in goats from the west and southwest of Iran. Journalaer 2026; 2 (1) :19-30 URL: http://journalaer.com/article-1-82-en.html