Molecular identification and phylogenetic positioning of nematodes Toxocara canis, T. cati (Ascarididae) and Toxascaris leonina (Toxocaridae) from domestic and wild carnivores in the Fergana Valley, Uzbekistan
Abstract
Parasitic nematodes of the superfamily Ascaridoidea infect various vertebrate groups, with certain species, partic u larly Toxocara , presenting significant zoonotic risks. This study aims to identify and characterize ascarid species in wild canines and felines in Namangan region, Uzbekistan. Ascarid samples were collected from 18 stray dogs, 3 jackals, and 12 stray cats between February 2023 and March 2025. Adult roundworms were examined using light microscopy and subjected to molecular analysis through PCR amplification of the partial ITS1-5,8S-ITS2 region of ribosomal DNA. Morphological examination identified the nematode samples from dogs and ja c kals as Toxocara canis and from dogs as Toxascaris leonina , while the sample from the cat was identified as Toxocara cati . The nucleotide sequences of ITS were analyzed for similarity using BLAST, which showed that these parasites are 99 – 100% identical to the species T. canis , T. cati and T. leonina . Phylogenetic relationships were also assessed using maximum likelihood analysis with the inclusion of additional sequences from GenBank (NCBI). Phylogenetic analysis showed that T. canis clustered with sequences from wild canids, while T. cati was associated with felids. Notably, T. leonina was divided into subclades depending on the host origin, suggesting the presence of a complex associated with host infectivity. Further confirm a tion is needed by increasing sample sizes and comparing a wider range of morphological and genetic data. This study provides new molecular data on the identification and epidemiological significance of ascarids in wild and domestic dogs and cats in Uzbekistan.References
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