1aechinococcus Thompson2002
1aechinococcus Thompson2002
1aechinococcus Thompson2002
Review
Concept of a strain
1471-4922/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S1471-4922(02)02358-9
Review
Echinococcus granulosus
Sheep strain (G1)
Sheep, cattle, pigs,
camels, goats,
macropods
Tasmanian sheep strain Sheep, cattle?
(G2)
Buffalo strain (?)
Buffalo, cattle?
Horse strain (G4)
Horses and other
equines
Cattle strain (G5)
Cattle
Camel strain (G6)
Camels, goats,
cattle?
Pig strain (G7)
Pigs
Cervid strain (G8)
Cervids
Lion strain
Zebra, wildebeest,
warthog, bushpig,
buffalo, various
Antelope, giraffe?
hippopotamus?
Echinococcus multilocularis
European isolate
Rodents, domestic
and wild pig, dog,
monkey
Alaskan isolate
Rodents
North American isolate Rodents
Hokkaido isolate
Rodents, pig,
monkey, horse
Echinococcus vogeli
None reported
Rodents
Echinococcus oligarthrus
None reported
Rodents
Yes
453
Proposed
taxonomic
b
designation
Echinococcus
granulosus
Yes
?
No
Dog, fox?
Dog
Yes
Dog
Yes
Dog
Asia
Europe, Middle East, South Africa,
(New Zealand? USA?)
Europe, South Africa, India, Sri Lanka,
Russian Federation, South America?
Middle East, Africa, China, Argentina
E. granulosus
Echinococcus
equinus
Echinococcus
ortleppi
E. granulosus?
Yes
Yes
?
Dog
Wolf, dog
Lion
Yes
Europe, China?
Echinococcus
multilocularis
Yes
Yes
Yes
Alaska
North America
Japan
E. multilocularis
E. multilocularis
E. multilocularis
Yes
Bush dog
Echinococcus vogeli
Yes
Wild felids
Echinococcus
oligarthrus
E. granulosus
454
Review
Molecular epidemiology
Review
455
Echinococcus equinus
Horse
Human
Dog, dingo,
wolf and fox
Echinococcus granulosus?
Pig
Dog
Echinococcus granulosus?
Camel
Sheep, cattle
and goat
Human?
Human
Dog
Dog
Possibly other canids?
Echinococcus granulosus?
Echinococcus ortleppi
Cervid
Cattle
Human
Human
Wolf
Dog
Dog
TRENDS in Parasitology
complete mt nucleotide sequences of the proteinencoding genes and of the two subunits of rRNA
(small; rrnS and large; rrnL) indicated that the sheep
and horse strains differed by 12.4% in their nucleotide
(nt), and 11.6% in their amino acid level (aa)
sequences, a level similar to differences between these
two genotypes and E. multilocularis (1315% nt; and
11.513.5% aa). As expected, divergence was
considerably higher when any member of the genus
Echinococcus was compared with T. crassiceps
(2630% differences in both nt and aa), suggesting that
saturation has not been reached within Echinococcus.
Sequences for the variable genes atp6 and nad3 were
obtained from additional genotypes of E. granulosus,
from Echinococcus vogeli and Echinococcus
oligarthrus. Again, pairwise comparisons showed the
distinctiveness of the G1 and G4 genotypes. Another
approach to investigating levels of divergence is by
means of phylogenetic trees (Box 2). Phylogenetic
analyses of concatenated atp6, nad1 (partial) and cox1
(partial) genes from E. multilocularis, E. vogeli,
E. oligarthrus, five genotypes of E. granulosus, and
using T. crassiceps as an outgroup, yielded the same
results. Overall, the comparisons reported suggested
that the horse and sheep strains are as distinct from
each other as either is from E. multilocularis.
http://parasites.trends.com
456
Review
Acknowledgements
R.C.A.T. acknowledges the
support provided by the
Australian Research
Council, WHO and
Murdoch University, and
the collaboration of Russ
Hobbs, Alan Lymbery,
John Eckert, Clare
Constantine, Majid Fasihi
Harandi and Lakshmi
Kumaratilake. D.P.M.
acknowledges the
National Health and
Medical Research Council
of Australia, the
Australian Research
Council, The Wellcome
Trust and the UNDP/World
Bank/WHO Special
Programme for Research
and Training in Tropical
Diseases for financial
support of his research.
D.P.M. also thanks
numerous collaborators,
especially Josephine
Bowles, Thanh Hoa Le,
David Blair, Mark Pearson
and Li Hua Zhang, for
their contribution to the
DNA analysis.
(b)
TRENDS in Parasitology
Review
Concluding comments
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