In the Dawn of an Early Invasion: No Genetic Diversity of <em>Angiostrongylus cantonensis</em> in Ecuador?

Abstract

The nematode Angiostrongylus cantonensis has been reported worldwide, however, some basic questions remain unanswered about the presence of A. cantonensis in Ecua-dor: 1) Was the invasion of A. cantonensis in Ecuador unique, or did it occur in different waves? 2) Was this invasion as recent as historical records suggest? 3) Did this inva-sion come from other regions of South America or elsewhere? To address these issues, we assessed the genetic diversity of MT-CO1 gene sequences from isolates obtained in eleven of Ecuador's 24 provinces. Our Bayesian inference phylogenetic tree recovered A. cantonensis as a well-supported monophyletic group. All eleven sequences from Ec-uador were identical and identified as AC17a. The haplotype AC17a, found in Ecuador and the USA, formed a cluster with AC17b (USA); AC13 (Thailand); and AC12a-b (Cambodia). It is notable that all the samples, obtained in different geographic and climatic regions of different Ecuadorian provinces, had no genetic difference between them. Despite the lack of genetic information on A. cantonensis in Latin America, ex-cept in Brazil, our finding differs from previous studies by its absence of genetic diver-sity in Ecuador. We concluded that the invasion of A. cantonensis in Ecuador may have occurred: 1) as a one-time event, 2) recently, and 3) from Asia via the USA. Further re-search should include samples from countries neighboring Ecuador to delve deeper in-to this.