Echinococcus across the north: Current knowledge, future challenges

Zoonotic Echinococcus spp. cestodes are present in almost all circumpolar nations, and have historically posed a risk to health of indigenous as well as other northern residents. However, surveillance data on both alveolar (AE) and cystic (CE) echinococcosis remains incomplete throughout the circump...

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Main Authors: Rebecca K. Davidson, Antti Lavikainen, Sergey Konyaev, Janna Schurer, Andrea L. Miller, Antti Oksanen, Karl Skírnisson, Emily Jenkins
Format: Article
Language:English
Published: Elsevier 2016-09-01
Series:Food and Waterborne Parasitology
Online Access:http://www.sciencedirect.com/science/article/pii/S2405676616300130
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author Rebecca K. Davidson
Antti Lavikainen
Sergey Konyaev
Janna Schurer
Andrea L. Miller
Antti Oksanen
Karl Skírnisson
Emily Jenkins
author_facet Rebecca K. Davidson
Antti Lavikainen
Sergey Konyaev
Janna Schurer
Andrea L. Miller
Antti Oksanen
Karl Skírnisson
Emily Jenkins
author_sort Rebecca K. Davidson
collection DOAJ
description Zoonotic Echinococcus spp. cestodes are present in almost all circumpolar nations, and have historically posed a risk to health of indigenous as well as other northern residents. However, surveillance data on both alveolar (AE) and cystic (CE) echinococcosis remains incomplete throughout the circumpolar region: Russia, Fennoscandia, Iceland, Greenland, Canada and Alaska (USA). Prevalence of Echinococcus spp. varies considerably in definitive canid hosts, animal intermediate hosts and accidental hosts like humans. Yet despite the high prevalence reported in canids in some geographic locations, human AE and CE are much less common than in endemic Asian and central European countries. This paper explores knowledge gaps and future challenges posed by Echinococcus spp. in eight circumpolar countries, a region where rapid environmental and social change are rewriting the boundaries, transmission, and impact of many pathogens, including zoonotic Echinococcus spp.Genotypes G6, G8 and G10 of Echinococcus canadensis are causative agents of human CE and have been identified in sylvatic (wild animal) and synanthropic (ecological association with humans) cervid-canine life cycles in the following northern regions: Alaska and northern Canada - G8 and G10; northern Russia - G6, G8, G10; and Fennoscandia - G10 in Finland - with no recent reports from Norway or Sweden. Echinococcus multilocularis, which causes AE, has been identified in a sylvatic arvicoline rodent-canine lifecycle in Alaska, Canada, Russia, Sweden and Svalbard (Norway). Asian, Mongolian, European and North American strains of E. multilocularis are found in Russia, with the North American N1 strain predominating in the north. The N1 strain is also found in Alaska, as well as Svalbard, whilst Asian strains have been identified in western Alaska. Central North American (N2) strain and European-type strains of E. multilocularis are present in Canada. Typing of the strain in Sweden is still pending. Individual human cases of AE with N2 and European-type strains are reported in North America, as well as multiple cases with Asian strains in Russia and historically on St Lawrence Island, Alaska (although genotyping of human cases was not available at the time). Echinococcus spp. have not been detected in Greenland and have been eliminated from Iceland.The predominance of E. multilocularis N1 strain and E. canadensis genotypes, in regions with high prevalence in definitive hosts yet low incidence of human AE and CE, suggests that these genotypes have lower zoonotic potential and pathogenicity than European and Asian strains of E. multilocularis and livestock genotypes of E granulosus sensu stricto. The continued monitoring of the emergence of Echinococcus genotypes within definitive and intermediate hosts, as well as people, is needed to assess the impact on public health risk, since the introduction of other genotypes could have serious repercussions. Lastly, determining risk factors and source attribution for human cases, including the possibility of food and waterborne transmission and the likelihood of autochthonous transmission, remain challenges. Keywords: Alveolar echinococcosis, Arctic, Circumpolar, Cystic echinococcosis, Genotypes
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spelling doaj.art-6723c5c174b544a5b710b46fc83c748e2022-12-22T00:07:13ZengElsevierFood and Waterborne Parasitology2405-67662016-09-0143953Echinococcus across the north: Current knowledge, future challengesRebecca K. Davidson0Antti Lavikainen1Sergey Konyaev2Janna Schurer3Andrea L. Miller4Antti Oksanen5Karl Skírnisson6Emily Jenkins7Norwegian Defence Research Establishment, Kjeller, Norway; Corresponding author at: Protection and Societal Security Division, Norwegian Defence Research Establishment, Postboks 25, 2027 Kjeller, Norway.University of Helsinki (FINPAR), Helsinki, FinlandInstitute Systematics and Ecology of Animals, Siberian Branch Russian Academy of Sciences, Novosibirsk, RussiaUniversity of Saskatchewan, Saskatoon, CanadaSwedish University of Agricultural Sciences, Uppsala, SwedenFinnish Food Safety Authority EVIRA (FINPAR), Oulu, FinlandUniversity of Iceland, IEFP Keldur, Reykjavík, IcelandUniversity of Saskatchewan, Saskatoon, CanadaZoonotic Echinococcus spp. cestodes are present in almost all circumpolar nations, and have historically posed a risk to health of indigenous as well as other northern residents. However, surveillance data on both alveolar (AE) and cystic (CE) echinococcosis remains incomplete throughout the circumpolar region: Russia, Fennoscandia, Iceland, Greenland, Canada and Alaska (USA). Prevalence of Echinococcus spp. varies considerably in definitive canid hosts, animal intermediate hosts and accidental hosts like humans. Yet despite the high prevalence reported in canids in some geographic locations, human AE and CE are much less common than in endemic Asian and central European countries. This paper explores knowledge gaps and future challenges posed by Echinococcus spp. in eight circumpolar countries, a region where rapid environmental and social change are rewriting the boundaries, transmission, and impact of many pathogens, including zoonotic Echinococcus spp.Genotypes G6, G8 and G10 of Echinococcus canadensis are causative agents of human CE and have been identified in sylvatic (wild animal) and synanthropic (ecological association with humans) cervid-canine life cycles in the following northern regions: Alaska and northern Canada - G8 and G10; northern Russia - G6, G8, G10; and Fennoscandia - G10 in Finland - with no recent reports from Norway or Sweden. Echinococcus multilocularis, which causes AE, has been identified in a sylvatic arvicoline rodent-canine lifecycle in Alaska, Canada, Russia, Sweden and Svalbard (Norway). Asian, Mongolian, European and North American strains of E. multilocularis are found in Russia, with the North American N1 strain predominating in the north. The N1 strain is also found in Alaska, as well as Svalbard, whilst Asian strains have been identified in western Alaska. Central North American (N2) strain and European-type strains of E. multilocularis are present in Canada. Typing of the strain in Sweden is still pending. Individual human cases of AE with N2 and European-type strains are reported in North America, as well as multiple cases with Asian strains in Russia and historically on St Lawrence Island, Alaska (although genotyping of human cases was not available at the time). Echinococcus spp. have not been detected in Greenland and have been eliminated from Iceland.The predominance of E. multilocularis N1 strain and E. canadensis genotypes, in regions with high prevalence in definitive hosts yet low incidence of human AE and CE, suggests that these genotypes have lower zoonotic potential and pathogenicity than European and Asian strains of E. multilocularis and livestock genotypes of E granulosus sensu stricto. The continued monitoring of the emergence of Echinococcus genotypes within definitive and intermediate hosts, as well as people, is needed to assess the impact on public health risk, since the introduction of other genotypes could have serious repercussions. Lastly, determining risk factors and source attribution for human cases, including the possibility of food and waterborne transmission and the likelihood of autochthonous transmission, remain challenges. Keywords: Alveolar echinococcosis, Arctic, Circumpolar, Cystic echinococcosis, Genotypeshttp://www.sciencedirect.com/science/article/pii/S2405676616300130
spellingShingle Rebecca K. Davidson
Antti Lavikainen
Sergey Konyaev
Janna Schurer
Andrea L. Miller
Antti Oksanen
Karl Skírnisson
Emily Jenkins
Echinococcus across the north: Current knowledge, future challenges
Food and Waterborne Parasitology
title Echinococcus across the north: Current knowledge, future challenges
title_full Echinococcus across the north: Current knowledge, future challenges
title_fullStr Echinococcus across the north: Current knowledge, future challenges
title_full_unstemmed Echinococcus across the north: Current knowledge, future challenges
title_short Echinococcus across the north: Current knowledge, future challenges
title_sort echinococcus across the north current knowledge future challenges
url http://www.sciencedirect.com/science/article/pii/S2405676616300130
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