Anisakis species (Nematoda: Anisakidae) of Dwarf Sperm Whale Kogia sima (Owen, 1866) stranded off the Pacific coast of southern Philippine archipelago

Anisakid nematodes in the Pacific region of the Philippine archipelago still remain unexplored. This study was carried out to identify anisakid species from one of their final hosts, the Kogiid whale (Dwarf Sperm Whale, Kogia sima) stranded off the southern part (Davao Gulf) of the Philippine archipelago. Anisakid worms were initially identified morphologically using light and scanning electron microscopy, whereas identification to species level was carried out molecularly using PCR-RFLP and sequencing of the ITS (ITS1-5.8s rRNA-ITS2) and mtDNA cox2 regions. Parasitological study revealed new geographical records for the presence of two Anisakis species (A. brevispiculata and A. typica) and two unknown Anisakis species that are genetically close, at mtDNA cox2 region, to A. paggiae and A. ziphidarum. Based on the molecular data on both genes, the current findings suggest possible occurrence of local variations or sibling species of A. paggiae and A. ziphidarum in the region. Given that Anisakis species have not been reported in the Philippine archipelago, their presence in the Dwarf Sperm Whale inhabiting this region indicates high possibility of Anisakis infections in the marine fishes, cephalopods and other intermediate hosts within the Philippine waters.