First report of molecular and phylogenetic analysis of Physaloptera praeputialis in naturally infected stray cats from India

Nematodes of the genus Physaloptera are globally distributed and infect a multitude of hosts. Their life cycle involves orthopterans and coleopterans as intermediate hosts. The morphological characters alone are inadequate to detect and differentiate Physaloptera spp. from its congeners. Moreover, molecular studies are limited to compare them precisely. The present communication reports the first molecular phylogenetic characterization of feline Physaloptera spp. from India based on mitochondrial cytochrome c oxidase subunit 1 (COX1) and small subunit ribosomal DNA (18S rDNA). The nematodes were first isolated from the stomach of adult stray cats during necropsy examination. Based on the gross and microscopic characters, the worms were identified as P. praeputialis. Morphological identification was further confirmed through PCR targeting the barcode region of the mitochondrial cytochrome c oxidase subunit I (MT-COI) gene, using nematode-specific primers cocktail followed by species specific primers targeting partial COX1 and 18S rRNA genes. Generated sequences were submitted in NCBI GenBank (MW517846, MW410927, MW411349), and phylogenetic trees were constructed using the maximum likelihood method. When compared with other sequences of Physaloptera species across the globe, the present isolates showed 85.6-97.7% and 97.3-99% nucleotide homology based on COX1 and 18S rRNA gene, respectively. BLASTn analysis revealed a strong identity to other Physaloptera spp., and the phylogenetic tree placed all Physaloptera spp. in the same cluster. This study again indicates the usefulness of molecular techniques to substantiate the identity of species that may lack adequate descriptions and impart new insight for the potentially overlooked significance of P. praeputialis infections in felines.