Parasitology



Molecular and morphological characterization of Echinococcus in cervids from North America


R. C. A. THOMPSON a1c1, A. C. BOXELL a1, B. J. RALSTON a2, C. C. CONSTANTINE a3, R. P. HOBBS a1, T. SHURY a4 and M. E. OLSON a5
a1 World Health Organization Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia
a2 Alberta Agriculture, Food and Rural Development, Airdrie, Alberta, Canada
a3 Division of Genetics and Bioinformatics, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3050, Australia
a4 Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
a5 Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada

Article author query
thompson rc   [PubMed][Google Scholar] 
boxell ac   [PubMed][Google Scholar] 
ralston bj   [PubMed][Google Scholar] 
constantine cc   [PubMed][Google Scholar] 
hobbs rp   [PubMed][Google Scholar] 
shury t   [PubMed][Google Scholar] 
olson me   [PubMed][Google Scholar] 

Abstract

Many issues concerning the taxonomy of Echinococcus have been resolved in recent years with the application of molecular tools. However, the status of Echinococcus maintained in transmission cycles involving cervid intermediate hosts remains to be determined. The recent characterization of the parasite from cervids in Finland has highlighted the paucity of data available, particularly that from North America. In this study, we have characterized a large number of Echinococcus isolates from cervids from Western Canada on the basis of morphology and molecular genetic techniques. Our results support earlier studies suggesting that Echinococcus of cervid origin is phenotypically and genetically distinct to Echinococcus maintained in domestic host assemblages, and also confirms that Echinococcus of cervid origin does not constitute a genetically homogeneous group. However, our data do not support the existence of 2 distinct genotypes (strains/subspecies) with separate geographical distributions. Our data appear to support the existence of only 1 species in cervids, but additional isolates from cervids and wolves in other endemic regions should be characterized before a final decision is made on the taxonomic status of Echinococcus in cervids.

(Received August 4 2005)
(Revised September 16 2005)
(Accepted September 16 2005)
(November 29 2005)


Key Words: Echinococcus; Echinococcus granulosus; cervids; Canada; molecular characterization; strains/genotypes/subspecies; mitochondrial (COI, NDI and ATP6); ITS-1; G8; G10.

Correspondence:
c1 WHO Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia. Tel: +61 08 9360 2466. Fax: +61 08 93104144. E-mail: andrew_t@central.murdoch.edu.au


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