Gnathostoma spinigerum larvae (AL3) were collected from the livers of naturally infected eels (Monopterus albus) in Thailand. The species was confirmed by molecular analysis of individual G. spinigerum larvae using a conventional polymerase chain reaction (PCR) protocol previously published by Jongthawin. Extraction kit was the QIAamp DNA Mini Kit (Qiagen) column extraction kit with the QIAcube (Qiagen). Nextera DNA Flex Library Prep kit (Illumina) was employed.