Research Article

Parasitic Anisakid Nematode Isolated from Stranded Fraser’s Dolphin (Lagenodelphis hosei Fraser, 1956) from Central Philippine Waters


Karl Marx A. Quiazon1,2,*, Mudjekeewis D. Santos3, Tomoyoshi Yoshinaga2

Abstract

Cetaceans, including dolphins, serve as definitive hosts of zoonotic anisakid nematodes, which are important etiological agents for human anisakiasis and allergy-associated health risks. With limited knowledge of these zoonotic parasites from the marine environment in the Philippine waters, the stranding of a Fraser’s dolphin (Lagenodelphis hosei Fraser, 1956) off the central Philippines made it possible to identify the worm species isolated from its gut. Parasitological examinations were carried out using morphological and molecular tools. Morphologically, the SEM and LM data revealed that the specimens belong to the genus Anisakis of the Type 1 group. Molecularly, PCR-RFLP results of the ITS region generated only a single fragment pattern on all worm samples corresponding to the reported molecular keys for A. typica. Further sequence and phylogenetic analyses of both ITS rDNA and mtDNA COX2 genes confirmed the anisakid nematodes’ identity as A. typica. The molecular data obtained in this study support previous findings on the possible existence of local variants of A. typica in this region.


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Keywords: Lagenodelphis hosei, Fraser’s dolphin, Anisakis typica, Philippines, PCR-RFLP, ITS rDNA, mtDNA COX2

Abbreviations: ITS–Internal Transcribed Spacer, LM–light microscope, mtDNA COX2–mitochondrial DNA cytochrome oxidase 2, PCR-RFLP–polymerase chain reaction-restriction fragment length polymorphism, SEM–scanning electron microscope


*Corresponding Author: karlmq@clsu.edu.ph

1Freshwater Aquaculture Center and College of Fisheries, Central Luzon State University, Science City of Muñoz, Nueva Ecija 3120, Philippines 2Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan 3Genetic Fingerprinting Laboratory, National Fisheries Research and Development Institute, 101 Mother Ignacia St., Quezon City 1103, Philippines

https://doi.org/10.31398/tpjf/27.2.2020-0007