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Current status of the genetics and molecular taxonomy of Echinococcus species

Published online by Cambridge University Press:  11 June 2013

D. P. McMANUS
D. P. McMANUS*
Affiliation:
Molecular Parasitology Laboratory, Queensland Institute of Medical Research, Brisbane, Queensland 4006, Australia
*
*Corresponding author. Molecular Parasitology Laboratory, Infectious Diseases Division, Queensland Institute of Medical Research, Herston, Brisbane, Queensland 4006, Australia. Tel: +61 7 362 0401. Fax: +61 7 3362 0104. E-mail: donm@qimr.edu.au
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Summary

The taxonomy of Echinococcus has long been controversial. Based mainly on differences in morphology and host-parasite specificity characteristics, 16 species and 13 subspecies were originally described. Subsequently, most of these taxa were regarded as synonyms for Echinococcus granulosus and only 4 valid species were recognised: E. granulosus; E. multilocularis; E. oligarthrus and E. vogeli. But, over the past 50 years, laboratory and field observations have revealed considerable phenotypic variability between isolates of Echinococcus, particularly those of E. granulosus, which include differences in: morphology in both larval and adult stages, development in vitro and in vivo, host infectivity and specificity, chemical composition, metabolism, proteins and enzymes, pathogenicity and antigenicity. The application of molecular tools has revealed differences in nucleic acid sequences that reflect this phenotypic variation and the genetic and phenotypic characteristics complement the previous observations made by the descriptive parasitologists many years ago. The fact that some of these variants or strains are poorly or not infective to humans has resulted in a reappraisal of the public health significance of Echinococcus in areas where such variants occur. A revised taxonomy for species in the Echinococcus genus has been proposed that is generally accepted, and is based on the new molecular data and the biological and epidemiological characteristics of host-adapted species and strains.

Keywords

Echinococcusstraingeneticsmolecular taxonomymitochondrial genomephylogenytaxonomic revision
Type
Research Article
Information
Parasitology , Volume 140 , Special Issue 13: Control of cestode zoonoses in Asia: role of basic and applied science , November 2013 , pp. 1617 - 1623
Copyright
Copyright © Cambridge University Press 2013 

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