First description of transposable elements of Angiostrongylus costaricensis - The causative agent of abdominal angiostrongyliasis in humans

Transposable elements (TEs) are important components of parasite genomes, but their diversity and contribution to genome organization remain poorly characterized in many parasitic nematodes. Here, we characterized the mobilome of Angiostrongylus costaricensis , the causative agent of abdominal angiostrongyliasis, using a curated species-specific TE library. TEs accounted for 35.94% of the genome and were dominated by retrotransposons, particularly LINEs (16.94%), followed by Penelope-like elements (PLEs; 8.98%) and SINEs (4.91%). Among LINEs, RTE elements represented the major component, whereas several PLE families retained potentially complete coding architectures. The LTR repertoire also revealed structural diversity, including a BEL/Pao element containing a phenuivirus-like envelope module composed of G1/Gn- and G2/Gc-like regions followed by a transmembrane segment. We also investigated potential horizontal transposon transfer between A. costaricensis and its vertebrate and invertebrate hosts, but no robust evidence of recent transfer was detected. Overall, these findings expand the genomic characterization of A. costaricensis and reveal a diverse TE repertoire that provides a basis for comparative studies of genome evolution in Angiostrongylus and other parasitic nematodes.