Molecular taxonomy, phylogeny and biogeography of nematodes belonging to the Trichinella genus

Abstract

Studying parasites of the genus Trichinella provides scientists of today many advantages. This is a group of zoonotic nematodes that circulates freely among wildlife hosts with one in particular, Trichinella spiralis that is exceptionally well adapted to domestic swine. Recent reports suggest that human infections from hunted animals are on the rise worldwide and numerous countries still experience problems with T. spiralis in their domestic food supplies. Trichinella is a genus whose members are easily propagated in the laboratories, have been used as models to investigate host-parasite relationships and parasitism among clade I organisms, and represent a poorly investigated link between the phylum Nematoda and other Metazoans. The importance of T. spiralis in better understanding the tree of life was so recognized that in 2004, its genome was carefully selected as one of only nine key non-mammalian organisms to be sequenced to completion. Since it was first discovered in 1835, this genus has expanded from being monospecific to eight species including four other genotypes of undetermined taxonomic rank. Inasmuch as discriminating morphological data have been scant, our understanding of the genus has been relegated to a compilation of molecular, biochemical and biological data. Herein, we provide a collection of information and up-to-date interpretations on the taxonomy, diagnostics, systematics, micro- and macroevolution, and the biogeographical and biohistorical reconstruction of the genus Trichinella.