First Report of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) Infections in Invasive Rodents from Five Islands of the Ogasawara Archipelago, Japan

Abstract

Background Angiostrongylus cantonensis (Chen, 1935) is a parasite of murid rodents and causative agent of human neuro-angiostrongyliasis. In 2011, the Ogasawara Islands in the western North Pacific were assigned a World Natural Heritage site status. The occurrence of A. cantonensis is well documented in the Chichijima, Hahajima, and Anijima Islands. However, the occurrence of A. cantonensis in the other islands of the Ogasawara Islands has not been reported.Methodology/Principal FindingsBetween March 2010 and July 2011, 57 Rattus norvegicus and 79 R. rattus were collected from 9 islands (the Hahajima group: Anejima, Imoutojima, Meijima, Mukohjima, and Hirajima; Chichijima group: Minamijima; Mukojima group: Nakoudojima and Yomejima; and Iwojima group: Iwojima). Adult nematodes were found in the pulmonary artery of 46 R. norvegicus collected in the 5 islands of the Hahajima group (Anejima, Meijima, Imoutojima, Hrajima, and Mukohjima Islands). These nematodes were identified by molecular analysis as A. cantonensis. Comparison of the mitochondrial DNA sequences confirmed that all the samples from the Ogasawara Islands shared only a single lineage of A. cantonensis, which has been previously detected in the Okinawa, Hawaii, and Brazil.Conclusions/SignificanceWe describe new endemic foci of rat angiostrongyliasis in the Hahajima group (Anejima, Meijima, Imoutojima, Hirajima, and Mukohjima Islands) of the Ogasawara Islands. These findings indicate that the endemic foci of A. cantonensis are widely distributed in the Ogasawara Islands. Although human cases have not yet been reported in the Ogasawara Islands, the widespread detection of A. cantonensis could be of importance from the perspective of public health.

Low diversity of Angiostrongylus cantonensis complete mitochondrial DNA sequences from Australia, Hawaii, French Polynesia and the Canary Islands revealed using whole genome next-generation sequencing

“…We speculate that the rapid spread of A. cantonensis in the Pacific region was a consequence of naval operations during and/or after the World War II, because troop and supply ships could readily permit spread of the A. cantonensis infected rats and/or snails. In a telling analogy, A. cantonensis repeatedly colonised Japan during the 20th century, spreading from southern islands to the north resulting in a presence of several different haplotypes from three clades [22].…”

“…Southeast Asia (including China, Taiwan, Vietnam, Thailand, Laos, Cambodia and Myanmar) is considered to be the original endemic region for A. cantonensis [21, 22, 27–35]. In Japan, Tokiwa et al [33] suggested colonization of the area by multiple genetic lineages spreading from the south to the north of Japan.…”

Hurdles in the evolutionary epidemiology of Angiostrongylus cantonensis: Pseudogenes, incongruence between taxonomy and DNA sequence variants, and cryptic lineages

“…For example, ribosomal DNA sequences were used to assess metastrongylid nematode relationships (Carreno & Nadler, 2003) or to help survey larvae from mollusk intermediate hosts (Fontanilla & Wade, 2008; Qvarnstrom, Sullivan, Bishop, Hollingsworth, & da Silva, 2007; Qvarnstrom et al., 2010), and ~360‐bp region of the cytochrome c oxidase 1 ( CO 1) gene was used to assess relationships to other species of Angiostrongylus (Eamsobhana et al., 2010). To date, molecular systematic/phylogeographic studies on A. cantonensis have mainly used two mitochondrial (mtDNA) markers, CO 1 and cytochrome b ( CYTB ), where the focus has largely been descriptive in terms of reporting local patterns of haplotype variants (Aghazadeh et al., 2015; Dalton, Fenton, Cleveland, Elsmo, & Yabsley, 2017; Dusitsittipon, Criscione, Morand, Komalamisra, & Thaenkham, 2017; Dusitsittipon, Thaenkham, Watthanakulpanich, Adisakwattana, & Komalamisra, 2015; Eamsobhana, Song, et al., 2017; Eamsobhana, Yong, et al., 2017; Lv et al., 2012; Monte et al., 2012; Moreira et al., 2013; Nakaya et al., 2013; Okano et al., 2014; Rodpai et al., 2016; Simoes et al., 2011; Tokiwa et al., 2012, 2013; Vitta et al., 2016; Yong, Eamsobhana, Song, Prasartvit, & Lim, 2015; Yong, Song, Eamsobhana, Goh, & Lim, 2015; Yong, Song, Eamsobhana, & Lim, 2016). …”

A Peculiar Distribution of the Emerging Nematode Angiostrongylus cantonensis in the Canary Islands (Spain): Recent Introduction or Isolation Effect?

“…One of the theories for the appearance of this nematode outside of Southeast Asia is that its spread has been facilitated by the introduction of the giant African snail, Achatina fulica, which could have carried the parasite across the Pacific where rat populations were already established [21][22][23]. Hochberg et al (2007) [24] proposed that the spread of A. cantonensis has been driven by climate change factors and globalization, as well as by the increasing international trade.…”