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Molecular characterization of Echinococcus isolates of cervid origin from Finland and Sweden

  • A. LAVIKAINEN (a1), M. J. LEHTINEN (a1), S. LAAKSONEN (a2), E. ÅGREN (a3), A. OKSANEN (a2) and S. MERI (a4)...


The species Echinococcus granulosus is made up of several genotypic strain groups, whose taxonomical classification is still undetermined. Genotypes in the cervid-wolf life-cycle are poorly known, especially in Europe. In this study, 33 Echinococcus isolates from cervids from Finland and Sweden were characterized using mitochondrial ND1 gene sequencing. In addition, phylogenetic analysis of E. granulosus strains using the mitochondrial ATP6, ND1, ND3 and CO1 genes was performed using maximum likelihood, neighbour-joining and maximum parsimony methods. The Finnish and Swedish cervid isolates were found to represent the genotype G10. In the phylogenetic analyses, the camel (G6), pig (G7), cervid (G8) and Fennoscandian cervid (G10) strains clustered in a well-supported monophyletic group. This group differed clearly from the common sheep (G1) and horse (G4, ‘E. equinus’) strains, but was closely related to the cattle strain (G5, ‘E. ortleppi’). Our results support the previous studies suggesting that the genotypes G6-10 should be separated from the species E. granulosus sensu stricto. However, additional morphological studies are needed, and the relationship to the cattle strain (‘E. ortleppi’) should be thoroughly evaluated before a final decision of the taxonomical status of the G6-10 group can be made.


Corresponding author

Department of Bacteriology and Immunology, Haartman Institute, P.O. Box 21, FIN-00014, University of Helsinki, Finland. Tel: +358 9 191 26373. Fax: +358 9 191 26382. E-mail:


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Aronson, Å. and Sand, H. ( 2004). Om vargens utveckling i Skandinavien under de senaste 30 åren. In Skogsvilt III: vilt och landskap i förändring ( ed. Jansson, G., Seiler, C. and Andrén, H.), pp. 4753. Bergslagens grafiska AB, Lindesberg.
Bowles, J., Blair, D. and McManus, D. P. ( 1992). Genetic variants within the genus Echinococcus identified by mitochondrial DNA sequencing. Molecular and Biochemical Parasitology 54, 165174.
Bowles, J., Blair, D. and McManus, D. P. ( 1994). Molecular genetic characterization of the cervid strain (‘northern form’) of Echinococcus granulosus. Parasitology 109, 215221.
Bowles, J. and McManus, D. P. ( 1993). NADH dehydrogenase 1 gene sequences compared for species and strains of the genus Echinococcus. International Journal for Parasitology 23, 969972.
Flisser, A., Viniegra, A.-E., Aguilar-Vega, L., Garza-Rodriquez, A., Maravilla, P. and Avila, G. ( 2004). Portrait of human tapeworms. Journal of Parasitology 90, 914916.
Gasser, R. B., Zhu, X. and McManus, D. P. ( 1999). NADH dehydrogenase subunit 1 and cytochrome c oxidase subunit I sequences compared for members of the genus Taenia (Cestoda). International Journal for Parasitology 29, 19651970.
Hirvelä-Koski, V., Haukisalmi, V., Kilpelä, S.-S., Nylund, M. and Koski, P. ( 2003). Echinococcus granulosus in Finland. Veterinary Parasitology 111, 175192.
Hoberg, E. P. ( 2006). Phylogeny of Taenia: species definitions and origins of human parasites. Parasitology International 55, S23S30. doi: 10.1016/j.parint.2005.11.049.
Jenkins, D. J., Romig, T. and Thompson, R. C. A. ( 2005). Emergence/re-emergence of Echinococcus spp. – a global update. International Journal for Parasitology 35, 12051219.doi: 10.1016/j.ijpara.2005.07.014.
Jeon, H. K., Lee, K. H., Kim, K. H., Hwang, U. W. and Eom, K. S. ( 2005). Complete sequence and structure of the mitochondrial genome of the human tapeworm, Taenia asiatica (Platyhelminthes; Cestoda). Parasitology 130, 717726. doi: 10.1017/S0031182004007164.
Kikot', V. I. ( 1980). Natural foci of echinococcosis in the mountain-taiga zone of the Far East [In Russian]. Meditsinskaya Parazitologiya i Parazitarnye Bolezni 49, 6064.
Lavikainen, A. ( 2005). Ihmisen ekinokokkitauti Suomen, Ruotsin ja Norjan Lapissa. Suomen Eläinlääkärilehti 110, 713.
Lavikainen, A., Lehtinen, M. J., Meri, T., Hirvelä-Koski, V. and Meri, S. ( 2003). Molecular genetic characterization of the Fennoscandian cervid strain, a new genotypic group (G10) of Echinococcus granulosus. Parasitology 127, 207215. doi: 10.1017/S0031182003003780.
Le, T. H., Blair, D., Agatsuma, T., Humair, P.-F., Campbell, N. J. H., Iwagami, M., Littlewood, D. T. J., Peacock, B., Johnston, D. A., Bartley, J., Rollinson, D., Herniou, E. A., Zarlenga, D. S. and McManus, D. P. ( 2000). Phylogenies inferred from mitochondrial gene orders – a cautionary tale from the parasitic flatworms. Molecular Biology and Evolution 17, 11231125.
Le, T. H., Pearson, M. S., Blair, D., Dai, N., Zhang, L. H. and McManus, D. P. ( 2002). Complete mitochondrial genomes confirm the distinctiveness of the horse-dog and sheep-dog strains of Echinococcus granulosus. Parasitology 124, 97112. doi: 10.1017/S0031182001008976.
Loos-Frank, B. ( 2000). An up-date of Verster's (1969) ‘Taxonomic revision of the genus Taenia Linnaeus’ (Cestoda) in table format. Systematic Parasitology 45, 155183.
Maijala, R., Haukisalmi, V., Henttonen, H., Hirvelä-Koski, V., Kauhala, K., Kilpelä, S.-S., Lavikainen, A., Oksanen, A., Tenhu, H. and Vahteristo, L. ( 2002). Risk Assessment on Echinococcus granulosus in Finland. National Veterinary and Food Research Institute (EELA), Helsinki (; availability confirmed March 9th, 2006).
McManus, D. P., Zhang, L., Castrodale, L. J., Le, T. H., Pearson, M. and Blair, D. ( 2002). Short report: molecular genetic characterization of an unusually severe case of hydatid disease in Alaska caused by the cervid strain of Echinococcus granulosus. American Journal of Tropical Medicine and Hygiene 67, 296298.
Moks, E., Saarma, U., Talvik, H. and Valdmann, H. ( 2005). Helmithological survey of wild canids in Estonia. In Extended Abstracts of the XXVIIth Congress of the International Union of Game Biologists, Hannover 2005 ( ed. Pohlmeyer, K.), p. 421. DSV-Verlag, Hamburg.
Nakao, M., Sako, Y., Yokoyama, N., Fukunaga, M. and Ito, A. ( 2000). Mitochondrial genetic code in cestodes. Molecular and Biochemical Parasitology 111, 415424.
Nakao, M., Yokoyama, N., Sako, Y., Fukunaga, M. and Ito, A. ( 2002). The complete mitochondrial DNA sequence of the cestode Echinococcus multilocularis (Cyclophyllidea: Taeniidae). Mitochondrion 1, 497509.
Posanda, D. and Crandall, K. A. ( 1998). MODELTEST: testing the model of DNA substitution. Bioinformatics 14, 817818.
Scott, J. C., Stefaniak, J., Pawlowski, Z. S. and McManus, D. P. ( 1997). Molecular genetic analysis of human cystic hydatid cases from Poland: identification of a new genotypic group (G9) of Echinococcus granulosus. Parasitology 114, 3743.
Sweatman, G. K. and Williams, R. J. ( 1963). Comparative studies on the biology and morphology of Echinococcus granulosus from domestic livestock, moose and reindeer. Parasitology 53, 339390.
Söderhjelm, L. ( 1945). Förekomsten av Echinococcus hydatidosus hos människan och ren (Rangifer tarandus). Svenska Läkartidningen 42, 19101916.
Tamura, K. and Nei, M. ( 1993). Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. Molecular Biology and Evolution 10, 512526.
Thompson, J. D., Higgins, D. G. and Gibson, T. J. ( 1994). CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Research 22, 46734680.
Thompson, R. C. A. ( 2002). Presidential address: rediscovering parasites using molecular tools – towards revising the taxonomy of Echinococcus, Giardia and Cryptosporidium. International Journal for Parasitology 32, 493496.
Thompson, R. C. A., Boxell, A. C., Ralston, B. J., Constantine, C. C., Hobbs, R. P., Shury, T. and Olson, M. E. ( 2006). Molecular and morphological characterization of Echinococcus in cervids from North America. Parasitology 132, 439447. doi: 10.1017/S0031182005009170.
Thompson, R. C. A., Lymbery, A. J. and Constantine, C. C. ( 1995). Variation in Echinococcus: towards a taxonomic revision of the genus. Advances in Parasitology 35, 146176.
Thompson, R. C. A. and McManus, D. P. ( 2002). Towards a taxonomic revision of the genus Echinococcus. Trends in Parasitology 18, 452457.
Xiao, N., Qiu, J., Nakao, M., Li, T., Yang, W., Chen, X., Schantz, P. M., Craig, P. S. and Ito, A. ( 2005). Echinococcus shiquicus n. sp., a taeniid cestode from Tibetan fox and plateau pika in China. International Journal for Parasitology 35, 693701. doi: 10.1016/j.ijpara.2005.01.003.
Yamasaki, H., Allan, J. C., Sato, M. O., Nakao, M., Sako, Y., Nakaya, K., Qiu, D., Mamuti, W., Craig, P. S. and Ito, A. ( 2004). DNA Differential diagnosis of taeniasis and cysticercosis by multiplex PCR. Journal of Clinical Microbiology 42, 548553. doi: 10.1128/JCM.42.2.548–553.2004.


Molecular characterization of Echinococcus isolates of cervid origin from Finland and Sweden

  • A. LAVIKAINEN (a1), M. J. LEHTINEN (a1), S. LAAKSONEN (a2), E. ÅGREN (a3), A. OKSANEN (a2) and S. MERI (a4)...


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