a1 Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Ap. Postal 70-153, C. P. 04510, Mexico
a2 Division of Genetics and Bioinformatics, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3050, Australia
a3 World Health Organisation Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia
Samples of Echinococcus granulosus from seven pigs from Mexico were compared with isolates of the parasite from pigs in Poland and representative strains and species of Echinococcus. Isolates from pigs in Mexico were found to be genetically identical to E. granulosus from Polish pigs and distinct from other major genotypes by sequencing part of the mitochondrial cytochrome c oxidase I (COI) mtDNA locus, restriction fragment length polymorphism (RFLP) of the polymerase chain reaction (PCR) amplified rDNA internal transcribed spacer (ITS) 1 using five different enzymes, and random amplified polymorphic DNA (RAPD) analysis. These results were complemented by data on hook morphology and together strengthen the view that Echinococcus maintained in a cycle involving pigs and dogs is a distinct strain that is conserved genetically in different geographical areas. The present study supports the close relationship of the cervid, camel and pig strains and raises the question of their taxonomic status.
(Accepted December 13 2006)
(Online publication June 12 2007)