Molecular Genotyping of Anisakis Larvae in Middle Eastern Japan and Endoscopic Evidence for Preferential Penetration of Normal over Atrophic Mucosa

Abstract

BackgroundAnisakiasis is a parasitic disease caused primarily by Anisakis spp. larvae in Asia and in Western countries. The aim of this study was to investigate the genotype of Anisakis larvae endoscopically removed from Middle Eastern Japanese patients and to determine whether mucosal atrophy affects the risk of penetration in gastric anisakiasis.MethodsIn this study, 57 larvae collected from 44 patients with anisakiasis (42 gastric and 2 colonic anisakiasis) were analyzed retrospectively. Genotyping was confirmed by restriction fragment length polymorphism (RFLP) analysis of ITS regions and by sequencing the mitochondrial small subunit (SSU) region. In the cases of gastric anisakiasis, correlation analyses were conducted between the frequency of larval penetration in normal/atrophic area and the manifestation of clinical symptoms.ResultsNearly all larvae were A. simplex seusu stricto (s.s.) (99%), and one larva displayed a hybrid genotype. The A. simplex larvae penetrated normal mucosa more frequently than atrophic area (p = 0.005). Finally, patients with normal mucosa infection were more likely to exhibit clinical symptoms than those with atrophic mucosa infection (odds ratio, 6.96; 95% confidence interval, 1.52–31.8).ConclusionsIn Japan, A. simplex s.s. is the main etiological agent of human anisakiasis and tends to penetrate normal gastric mucosa. Careful endoscopic examination of normal gastric mucosa, particularly in the greater curvature of the stomach will improve the detection of Anisakis larvae.

Molecular identification of Anisakis and Hysterothylacium larvae in marine fishes from the East China Sea and the Pacific coast of central Japan

“…In Japan, A. simplex s.s. is the most important etiological agent as reported that 84 out of the 85 patients (98.8%) were infected with A. simplex s.s. while one patient (1.2%) infected with A. pegreffii (Umehara et al, 2007). Recently, 57 larvae collected from 44 patients with anisakiasis from Middle Eastern Japan were analyzed retrospectively and nearly all larvae were A. simplex s.s. (99%) while one larva displayed a hybrid genotype (Arai et al, 2014). A. simplex s.s. larvae have the potential to survive acidic gastric juice to some extent and penetrate the stomach, small intestine, or colon in infected humans (Arizono et al, 2012).…”

Species-specific Real Time-PCR primers/probe systems to identify fish parasites of the genera Anisakis , Pseudoterranova and Hysterothylacium (Nematoda: Ascaridoidea)

“…are the causative agents of human anisakiasis and pseudoterranoviasis, respectively (Ishikura and Kikuchi, 1990;Daschner et al, 2012;Nieuwenhuizen, 2016). Among the species of Anisakis so far genetically characterized (Mattiucci and Nascetti, 2008;Mattiucci et al, 2009), only A. pegreffii and A. simplex (s. s.) have been documented to cause infections in humans (D'Amelio et al, 1999;Umehara et al, 2007;Fumarola et al, 2009;Moschella et al, 2004;Mattiucci et al, 2011Mattiucci et al, , 2013Qin et al, 2013;Arai et al, 2014;Lim et al, 2015). Among the species of the genus Pseudoterranova so far genetically characterized (Mattiucci and Nascetti, 2008;Timi et al, 2014), human cases of pseudoterranoviasis are reported as inflicted by P. azarasi (Arizono et al, 2011) and P. decipiens (s. s.) (Cavallero et al, 2016).…”

Invasive anisakiasis by the parasite Anisakis pegreffii (Nematoda: Anisakidae): diagnosis by real-time PCR hydrolysis probe system and immunoblotting assay

“…A. pegreffii is not the only species able to cause human anisakiasis. In Japan, Umehara et al [ 14 ] and Arai et al [ 15 ] recognized A. simplex (s .s.) as the main etiological agent of anisakiasis in a large number of patients.…”

“…A. pegreffii is the most widespread anisakid species affecting commercial fish from Mediterranean waters; its geographical distribution includes the Iberian Atlantic coast waters, as well as the Atlantic and Pacific Austral waters [ 7 , 8 ]. Indeed, so far A. pegreffii is reported as causative agent of invasive anisakiasis in Europe (Italy, Croatia) [ 9 – 13 ], but also in Japan [ 14 , 15 ] and South Korea [ 16 ]. It has been demonstrated with molecular markers that A. pegreffii is able to cause gastric [ 9 , 10 , 12 , 14 – 16 ], intestinal [ 11 , 13 ] anisakiasis and gastroallergic anisakiasis [ 12 ].…”