A multi-restriction fragment length polymorphism genotyping approach including the beta-tubulin gene as a new differential nuclear marker for the recognition of the cryptic species Anisakis simplex s.s. and Anisakis pegreffii and their hybridization events

Hybrid Genotype of Anisakis simplex (s.s.) and A. pegreffii Identified in Third- and Fourth-Stage Larvae from Sympatric and Allopatric Spanish Marine Waters

“…More recently, several authors have identified hybrids between A. simplex (s.s.) and A. pegreffii using novel diagnostic markers from the nuclear genomes, such as the beta-tubulin gene and the nas10 nDNA region, thus expanding the range of markers available for the multi-marker genotyping approach to Anisakis species classification [ 21 , 22 ].…”

“…In the present work, a hybrid genotype was also identified in seven L4 larval specimens obtained by in vitro culture, which showed no differences in in vitro culture behaviour or the moulting process in comparison with A. simplex (s.s.) and A. pegreffii . No L4 larvae with a hybrid genotype have been described in definitive hosts and few hybrid adults have been identified [ 10 , 21 , 35 ]. Consequently, it has been suggested that Anisakis hybrid specimens have low fertility and/or reduced fitness, which could affect their survival and therefore their detection and identification in definitive hosts [ 12 , 36 ].…”

Prevalence and molecular identification of zoonotic Anisakis and Pseudoterranova species in fish destined to human consumption in Chile

“…A. pegreffii, previously indicated as A. simplex A (Nascetti et al 1986), is mainly distributed in the Mediterranean Sea and in the Southern hemisphere (Abollo et al 2003) including South African coast, South Pacific Ocean (New Zealand), and Falkland Islands (Mattiucci and Nascetti 2007) and in the Austral Region between 30° S and 60° S, both in the larval and adult stages (Mattiucci et al 2018;Bello et al 2020). It is also widespread in the Pacific Boreal region including Japan Sea and China Sea (Gomez-Mateos et al 2020;Gomes et al 2021). Moreover, the genetic homogeneity between Mediterranean populations and those from Austral region seems to be maintained by the high levels of gene flow observed in this species allowing the hypothesis of its wide occurrence also in other areas of the Southern hemisphere (Mattiucci and Nascetti 2006;Mattiucci et al 2018).…”

“…In Chile, fish preys of snoeks and Chilean hakes have also been reported to be infected with anisakid larvae indicating that these two piscivorous species could clearly act as paratenic hosts in epizootiology of anisakiasis (Valdivia et al 2007;George-Nascimento and Moscoso 2013;Silva et al 2020) being also trophically transmitted among diverse marine species (Valdivia et al 2007). More importantly, Chilean hakes are one of the main pray fish of South American sea lions (Otaria flavescens) in this region, thereby probably representing a pivotal role transmission routes of anisakiasis (George-Nascimento and Llanos 1995; González-Saldía et al 2015) and contributing to the perpetuation of life cycle. However, the role of snoeks and sea breams as intermediate and/or paratenic hosts as well as marine invertebrates in the biology of these parasites in this Chilean region has not yet been fully clarified.…”

Population Genetic Structure of Anisakis simplex Infecting the European Hake from North East Atlantic Fishing Grounds

“…The genetic differentiation between the sibling species of A. simplex complex and hybrids A. simplex x A. pegreffii is crucial to understand their epidemiology, ecology and zoonotic potential. Several molecular markers have been described for this purpose, among them PCR-RFLPs profiles of ITS rDNA region [8]; nuclear markers sequencing of EF1 α1 nDNA region [30] or beta-tubulin gene [31] and an ARMS-PCR protocol based on nas 10 nDNA [32]; mitocondrial markers as cytochrome c oxidase subunit II (cox2) [33] or even panels of microsatellite loci to distinguish between A. simplex and A. pegreffii [34,35]. However, the results in detecting hybrids are not always consistent.…”