Molecular identification of Raillietina echinobothrida (Davaineidae) from domestic chickens in the Fergana Valley, Uzbekistan.

Raillietina species are among the most common cestodes of backyard chickens, but their morphological similarity complicates reliable species-level identification. This study aimed to identify Raillietina echinobothrida from domestic chickens (Gallus gallus domesticus) in the Fergana Valley, Uzbekistan, combining morphological examination with molecular analysis of the internal transcribed spacer 2 (ITS-2). Between 2021 and 2024, 80 chickens from rural households in Vodil, Sultonobod and Mirzaobod were examined by complete helminthological dissection. Recovered cestodes were assessed morphologically, and three specimens were subjected to PCR and Sanger sequencing of the ITS region (GenBank accessions PQ360975, PZ581203 and PZ581202); the ITS-2 fragment was used for comparison. Raillietina specimens were detected in 25.0% (20/80; 95% CI: 16.8-35.5) of the chickens (mean intensity 8.3 ± 4.0 worms per infected bird; range 2-15). Morphological characters agreed with published descriptions of R. echinobothrida. BLAST analysis of the 385 bp ITS-2 fragment showed the highest similarity to R. echinobothrida from Iraq (98.44%) and Thailand (97.39%), and maximum likelihood analysis grouped the Fergana specimens with reference sequences of this species. These findings confirm the assignment of the Uzbek material to R. echinobothrida and support combining morphological and ITS-2-based approaches for reliable identification of Raillietina species.