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

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.

Anisakid nematodes in Trichiurus lepturus and Saurida undosquamis (Teleostea) from the South-West Indian Ocean: Genetic evidence for the existence of sister species within Anisakis typica (s.l.), and food-safety considerations

“…A. In this respect, it would be diriment to investigate adult stages of both taxa in their definitive hosts, as was attempted by Quiazon et al (2020) from a stranded specimen of Fraser's dolphin, Lagenodelphis hosei , from central Philippine waters. Unfortunately, the authors could only obtain fragmented or degraded adult stage worms, which did not allow to perform a full morphological description.…”

“…Hence, based solely on genetic sequence analysis, these worms were identified as A. typica (s.l.) ( Quiazon et al, 2020 ). Interestingly, these specimen sequences ( cox 2, KF356648; ITS, KF356673; Quiazon et al, 2020 ), clustered with A. typica sp.…”

“…( Quiazon et al, 2020 ). Interestingly, these specimen sequences ( cox 2, KF356648; ITS, KF356673; Quiazon et al, 2020 ), clustered with A. typica sp. B (clade B) in both phylogenetic trees inferred by mtDNA cox 2 and ITS sequences analysis.…”

“…indonesiensis A. typica B L3 Brama cf. orcini Indonesia KY524198 Palm et al, 2017 A. typica A. typica B A Lagenodelphis hosei Phillippines KF356673 Quiazon et al, 2020 A. typica A. typica B L3 Scomberomorus niphonius China: South China Sea KP326555 Zhao et al, 2016 A. typica * A. typica B A Tursiops aduncus Northern Red Sea HF911524 Kleinertz et al, 2014 Anisakis sp. P. ceticola A Kogia sima Phillippines KC342892 Quiazon et al, 2013 A. paggiae A. paggiae L3 – – JQ912695 Mattiucci et al, 2014 A. brevispiculata A. brevispiculata – – – JQ912694 Mattiucci et al, 2014 A. physeteris A. physeteris – – – JQ912693 Mattiucci et al, 2014 A. berlandi A. berlandi – – – JX535519 Mattiucci et al, 2014 A. simplex (s.s.) A. simplex (s.s.) – – – JX535521 Mattiucci et al, 2014 …”

“…Adult individuals of this species were originally described from Delphinus delphis in the Central Atlantic Ocean (Diesing, 1860). Since then, A. typica has been frequently recorded in temperate waters of the Atlantic and Indo-Pacific oceans, both at the adult stage from several dolphin species ( Colón-Llavina et al, 2009 ; Gomes et al, 2021 ; Iñiguez et al, 2009 , Iñiguez et al, 2011 ; Mattiucci et al, 2002 ; Mattiucci and Nascetti, 2008 ; Quiazon et al, 2020 ), and at the larval stage in numerous fishes ( Mattiucci et al, 2018 ; Shamsi, 2021 ). In recent years, a new taxon genetically distinct from all known species of Anisakis but closely related to A. typica, has been found at the larval stage in several fish hosts from tropical temperate waters of the Indo-Pacific area ( Mattiucci and Nascetti, 2008 ; Mattiucci et al, 2018 ).…”