The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Akira Ito - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic systematics of the genus Echinococcus (Cestoda: Taeniidae)
International Journal for Parasitology, 2013Co-Authors: Minoru Nakao, Antti Lavikainen, Tetsuya Yanagida, Akira ItoAbstract:Echinococcosis is a serious helminthic zoonosis in humans, livestock and wildlife. The pathogenic organisms are members of the genus Echinococcus (Cestoda: Taeniidae). Life cycles of Echinococcus spp. are consistently dependent on predator–prey association between two obligate mammalian hosts. Carnivores (canids and felids) serve as definitive hosts for adult tapeworms and their herbivore prey (ungulates, rodents and lagomorphs) as intermediate hosts for metacestode larvae. Humans are involved as an accidental host for metacestode infections. The metacestodes develop in various internal organs, particularly in liver and lungs. Each metacestode of Echinococcus spp. has an organotropism and a characteristic form known as an unilocular (cystic), alveolar or polycystic hydatid. Recent molecular phylogenetic studies have demonstrated that the type species, Echinococcus granulosus, causing cystic echinococcosis is a cryptic species complex. Therefore, the orthodox taxonomy of Echinococcus established from morphological criteria has been revised from the standpoint of phylogenetic systematics. Nine valid species including newly resurrected taxa are recognised as a result of the revision. This review summarises the recent advances in the phylogenetic systematics of Echinococcus, together with the historical backgrounds and molecular epidemiological aspects of each species. A new phylogenetic tree inferred from the mitochondrial genomes of all valid Echinococcus spp. is also presented. The taxonomic nomenclature for Echinococcus oligarthrus is shown to be incorrect and this name should be replaced with Echinococcus oligarthra.
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Echinococcus species from red foxes, corsac foxes, and wolves in Mongolia.
Parasitology, 2013Co-Authors: Akira Ito, Tetsuya Yanagida, Gantigmaa Chuluunbaatar, Anu Davaasuren, Battulga Sumiya, Mitsuhiko Asakawa, Kazuhiro Nakaya, Abmed Davaajav, Temuulen DorjsurenAbstract:The small intestines of 420 wild canids (111 corsac foxes, 191 red foxes and 118 wolves) from Mongolia, were examined for adult worms of the genus Echinococcus. The Mongolian genotype of Echinococcus multilocularis was found in fifteen red foxes and four wolves, whereas two genotypes (G6/7 and G10) of Echinococcus canadensis were found in two and three wolves, respectively. No adult Echinococcus worms were found in the corsac foxes examined. The genotypes of E. multilocularis and E. canadensis are discussed in terms of host specificity and distribution in Mongolia. The importance of wolves in the completion of the life cycle of Echinococcus spp. is also discussed.
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Echinococcus vogeli infection in a hunter, French Guiana.
Emerging Infectious Diseases, 2009Co-Authors: Jenny Knapp, Minoru Nakao, Akira Ito, Mircea Chirica, Christine Simonnet, Frederic Grenouillet, Jean Mathieu Bart, Yasuhito Sako, Sonoyo Itoh, Laurence MillonAbstract:Echinococcus vogeli infection in a hunter from the rain forest of French Guiana was confirmed by imaging and mitochondrial DNA sequence analysis. Serologic examination showed typical patterns for both alveolar and cystic echinococcosis. Polycystic echinococcis caused by E. vogeli may be an emerging parasitic disease in Central and South America.
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Biological features of a new Echinococcus species (Echinococcus shiquicus) in the east of Qinghai-Tibet Plateau
Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases, 2008Co-Authors: Ning Xiao, Minoru Nakao, Philip S Craig, Jiamin Qiu, Xingwang Chen, P.m. Schantz, Akira ItoAbstract:In the eastern Qinghai-Tibet Plateau region, a variety of domestic and wild mammals are involved in the transmission cycles of Echinococcus species. E. granulosus and E. multilocularis are known being sympatrically distributed in the plateau region. Recently, an unknown Echinococcus species was isolated from infected plateau pika (Ochotona curzoniae) and Tibetan fox (Vulpes ferrilata). The species shows quite distinct characteristics on morphology, genetics, host specificity and geographical distribution from others. It was therefore identified as a new Echinococcus species, Echinococcus shiquicus. This paper discussed the biological genetics and epidemiological features of the species, and proposed hypotheses and considerations for further exploration.
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Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China.
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Ning Xiao, Minoru Nakao, Patrick Giraudoux, Philip S Craig, Jiamin Qiu, Christine M Budke, Akira ItoAbstract:The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.
Philip S Craig - One of the best experts on this subject based on the ideXlab platform.
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Seasonal pattern of Echinococcus re-infection in owned dogs in Tibetan communities of Sichuan, China and its implications for control.
Infectious diseases of poverty, 2016Co-Authors: Qian Wang, Bo Zhong, Jing-ye Shang, Liang Huang, Alexander Mastin, Yan Huang, Guang-jia Zhang, Patrick Giraudoux, Philip S CraigAbstract:Human cystic echinococcosis (CE) and alveolar echinococcosis (AE) are highly endemic in Tibetan communities of Sichuan Province. Previous research in the region indicated that domestic dog was the major source of human infection, and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.: both domestic livestock (CE) viscera and small mammals (AE), in early winter and again in spring. We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp. in these two seasons and conducted a reinfection study to investigate this further. Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture (Sichuan Province, China), and Echinococcus spp. infection status was determined using copro-antigen ELISA. Dogs were sampled in April (spring), July (early summer), September/October (autumn/early winter) and December (winter) in 2009; and in April (spring) 2010. Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms. Information on dog sex, age and body weight was also collected. The t-test, Fisher's exact test, Poisson regression and logistic regression were used to compare means and prevalences, and to identify factors associated with infection status. The proportion of female dogs was significantly lower than that of male dogs; female dogs had significantly higher (22.78 %) baseline copro-ELISA prevalence than males (11.88 %). Dog body weight, sex, age, county and previous infection status at any sampling point had no influence on the re-infection prevalence in general. Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans. Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009, suggesting a higher infection pressure in these seasons comparing with other seasons. Following praziquantel treatment, dog body weight, sex, age, county, deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general. The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp. infection pressure in the region. Early winter, spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.
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Biological features of a new Echinococcus species (Echinococcus shiquicus) in the east of Qinghai-Tibet Plateau
Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases, 2008Co-Authors: Ning Xiao, Minoru Nakao, Philip S Craig, Jiamin Qiu, Xingwang Chen, P.m. Schantz, Akira ItoAbstract:In the eastern Qinghai-Tibet Plateau region, a variety of domestic and wild mammals are involved in the transmission cycles of Echinococcus species. E. granulosus and E. multilocularis are known being sympatrically distributed in the plateau region. Recently, an unknown Echinococcus species was isolated from infected plateau pika (Ochotona curzoniae) and Tibetan fox (Vulpes ferrilata). The species shows quite distinct characteristics on morphology, genetics, host specificity and geographical distribution from others. It was therefore identified as a new Echinococcus species, Echinococcus shiquicus. This paper discussed the biological genetics and epidemiological features of the species, and proposed hypotheses and considerations for further exploration.
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Impact of overgrazing on the transmission of Echinococcus multilocularis in Tibetan pastoral communities of Sichuan Province, China.
Chinese Medical Journal, 2007Co-Authors: Qian Wang, Philip S Craig, Peter M Schantz, Yong-fu Xiao, Dominique A Vuitton, Francis Raoul, Christine Budke, Maiza Campos-ponce, Patrick GiraudouxAbstract:BACKGROUND: Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plateau. This research tested the hypothesis that overgrazing might promote Echinococcus multilocularis transmission through increasing populations of small mammal, intermediate hosts in Tibetan pastoral communities. METHODS: Grazing practices, small mammal indices and dog Echinococcus multilocularis infection data were collected to analyze the relation between overgrazing and Echinococcus multilocularis transmission using nonparametric tests and multiple stepwise logistic regression. RESULTS: In the investigated area, raising livestock was a key industry. The communal pastures existed and the available forage was deficient for grazing. Open (common) pastures were overgrazed and had higher burrow density of small mammals compared with neighboring fenced (private) pastures; this high overgrazing pressure on the open pastures measured by neighboring fenced area led to higher burrow density of small mammals in open pastures. The median burrow density of small mammals in open pastures was independently associated with nearby canine Echinococcus multilocularis infection (P = 0.003, OR = 1.048). CONCLUSION: Overgrazing may promote the transmission of Echinococcus multilocularis through increasing the population density of small mammals.
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Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China.
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Ning Xiao, Minoru Nakao, Patrick Giraudoux, Philip S Craig, Jiamin Qiu, Christine M Budke, Akira ItoAbstract:The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.
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Echinococcus shiquicus a new species from the qinghai tibet plateau region of china discovery and epidemiological implications
Parasitology International, 2006Co-Authors: Ning Xiao, Minoru Nakao, Philip S Craig, Jiamin Qiu, Wen Yang, Xingwang Chen, Peter M Schantz, Akira ItoAbstract:In Shiqu County of the Qinghai–Tibet plateau, many wild and domestic mammals are involved in the transmission cycles of Echinococcus spp. Echinococcus multilocularis and Echinococcus granulosus genotype G1 (sheep strain) are sympatrically distributed in the plateau. In 1995, we identified a unique strobilate stage of Echinococcus from the Tibetan fox, Vulpes ferrilata, but considered it to be a variant of E. multilocularis. Subsequent molecular genetic studies revealed that a hydatid cyst from the plateau pika, Ochotona curzoniae, had unique mitochondrial DNA sequences which are dissimilar to any published sequences of Echinococcus. The same sequences were subsequently found in adult worms from Tibetan foxes. Morphological, genetic and ecological features of the cestode led us to designate a new species Echinococcus shiquicus. E. shiquicus has been found at other areas surveyed on the plateau; however, no infections in humans caused by E. shiquicus have been yet identified.
Patrick Giraudoux - One of the best experts on this subject based on the ideXlab platform.
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World surveillance and transmission ecology of Echinococcus species
2017Co-Authors: Patrick GiraudouxAbstract:The life-cycles of Echinococcus species range from merely sylvatic to merely domestic. Furthermore, several species and genotypes can co-exist locally in world ecosystems. There, the range of Echinococcus species and genotypes and the number of host species also pose substantial problems when it comes to understand life-cycle and exposure routes. Even within a single species such as Echinococcus multilocularis differences in transmission ecology can have important consequences in term of public health and optimization of control strategy. Those potentially applied issues call for reinforcing basic research on Echinococcus species and genotypes ecology. Based on examples, here we present an overview about the world ecosystems conducive to Echinococcus parasite transmission, and how anthropogenic disturbance can lead to transmission re-enforcement, sustained stability or to extinction in various conditions. We present why systems approach is essential to insert Echinococcus control in a larger scope where the ultimate causes of transmission can be taken into account. We illustrate this in describing how some surveillance systems work and how they could be improved or implemented elsewhere to better prevent public health hazards.
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Seasonal pattern of Echinococcus re-infection in owned dogs in Tibetan communities of Sichuan, China and its implications for control.
Infectious diseases of poverty, 2016Co-Authors: Qian Wang, Bo Zhong, Jing-ye Shang, Liang Huang, Alexander Mastin, Yan Huang, Guang-jia Zhang, Patrick Giraudoux, Philip S CraigAbstract:Human cystic echinococcosis (CE) and alveolar echinococcosis (AE) are highly endemic in Tibetan communities of Sichuan Province. Previous research in the region indicated that domestic dog was the major source of human infection, and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.: both domestic livestock (CE) viscera and small mammals (AE), in early winter and again in spring. We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp. in these two seasons and conducted a reinfection study to investigate this further. Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture (Sichuan Province, China), and Echinococcus spp. infection status was determined using copro-antigen ELISA. Dogs were sampled in April (spring), July (early summer), September/October (autumn/early winter) and December (winter) in 2009; and in April (spring) 2010. Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms. Information on dog sex, age and body weight was also collected. The t-test, Fisher's exact test, Poisson regression and logistic regression were used to compare means and prevalences, and to identify factors associated with infection status. The proportion of female dogs was significantly lower than that of male dogs; female dogs had significantly higher (22.78 %) baseline copro-ELISA prevalence than males (11.88 %). Dog body weight, sex, age, county and previous infection status at any sampling point had no influence on the re-infection prevalence in general. Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans. Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009, suggesting a higher infection pressure in these seasons comparing with other seasons. Following praziquantel treatment, dog body weight, sex, age, county, deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general. The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp. infection pressure in the region. Early winter, spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.
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Impact of overgrazing on the transmission of Echinococcus multilocularis in Tibetan pastoral communities of Sichuan Province, China.
Chinese Medical Journal, 2007Co-Authors: Qian Wang, Philip S Craig, Peter M Schantz, Yong-fu Xiao, Dominique A Vuitton, Francis Raoul, Christine Budke, Maiza Campos-ponce, Patrick GiraudouxAbstract:BACKGROUND: Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plateau. This research tested the hypothesis that overgrazing might promote Echinococcus multilocularis transmission through increasing populations of small mammal, intermediate hosts in Tibetan pastoral communities. METHODS: Grazing practices, small mammal indices and dog Echinococcus multilocularis infection data were collected to analyze the relation between overgrazing and Echinococcus multilocularis transmission using nonparametric tests and multiple stepwise logistic regression. RESULTS: In the investigated area, raising livestock was a key industry. The communal pastures existed and the available forage was deficient for grazing. Open (common) pastures were overgrazed and had higher burrow density of small mammals compared with neighboring fenced (private) pastures; this high overgrazing pressure on the open pastures measured by neighboring fenced area led to higher burrow density of small mammals in open pastures. The median burrow density of small mammals in open pastures was independently associated with nearby canine Echinococcus multilocularis infection (P = 0.003, OR = 1.048). CONCLUSION: Overgrazing may promote the transmission of Echinococcus multilocularis through increasing the population density of small mammals.
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Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China.
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Ning Xiao, Minoru Nakao, Patrick Giraudoux, Philip S Craig, Jiamin Qiu, Christine M Budke, Akira ItoAbstract:The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.
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Short report: Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Ning Xiao, Minoru Nakao, Patrick Giraudoux, Philip S Craig, Jiamin Qiu, Christine M Budke, Akira ItoAbstract:The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.
Minoru Nakao - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic systematics of the genus Echinococcus (Cestoda: Taeniidae)
International Journal for Parasitology, 2013Co-Authors: Minoru Nakao, Antti Lavikainen, Tetsuya Yanagida, Akira ItoAbstract:Echinococcosis is a serious helminthic zoonosis in humans, livestock and wildlife. The pathogenic organisms are members of the genus Echinococcus (Cestoda: Taeniidae). Life cycles of Echinococcus spp. are consistently dependent on predator–prey association between two obligate mammalian hosts. Carnivores (canids and felids) serve as definitive hosts for adult tapeworms and their herbivore prey (ungulates, rodents and lagomorphs) as intermediate hosts for metacestode larvae. Humans are involved as an accidental host for metacestode infections. The metacestodes develop in various internal organs, particularly in liver and lungs. Each metacestode of Echinococcus spp. has an organotropism and a characteristic form known as an unilocular (cystic), alveolar or polycystic hydatid. Recent molecular phylogenetic studies have demonstrated that the type species, Echinococcus granulosus, causing cystic echinococcosis is a cryptic species complex. Therefore, the orthodox taxonomy of Echinococcus established from morphological criteria has been revised from the standpoint of phylogenetic systematics. Nine valid species including newly resurrected taxa are recognised as a result of the revision. This review summarises the recent advances in the phylogenetic systematics of Echinococcus, together with the historical backgrounds and molecular epidemiological aspects of each species. A new phylogenetic tree inferred from the mitochondrial genomes of all valid Echinococcus spp. is also presented. The taxonomic nomenclature for Echinococcus oligarthrus is shown to be incorrect and this name should be replaced with Echinococcus oligarthra.
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Echinococcus vogeli infection in a hunter, French Guiana.
Emerging Infectious Diseases, 2009Co-Authors: Jenny Knapp, Minoru Nakao, Akira Ito, Mircea Chirica, Christine Simonnet, Frederic Grenouillet, Jean Mathieu Bart, Yasuhito Sako, Sonoyo Itoh, Laurence MillonAbstract:Echinococcus vogeli infection in a hunter from the rain forest of French Guiana was confirmed by imaging and mitochondrial DNA sequence analysis. Serologic examination showed typical patterns for both alveolar and cystic echinococcosis. Polycystic echinococcis caused by E. vogeli may be an emerging parasitic disease in Central and South America.
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genetic characterization and phylogenetic position of Echinococcus felidis cestoda taeniidae from the african lion
International Journal for Parasitology, 2008Co-Authors: Minoru Nakao, Yasuhito Sako, Marion Huttner, Torsten Wassermann, Ludwig Siefert, J Boomker, Anke Dinkel, Ute Mackenstedt, Thomas RomigAbstract:Echinococcus felidis had been described in 1937 from African lions, but was later included in Echinococcus granulosus as a subspecies or a strain. In the absence of any genetic characterization, most previous records of this taxon from a variety of large African mammals remained unconfirmed due to the lack of diagnostic criteria and the possible confusion with the sympatric E. granulosus sensu stricto, Echinococcus ortleppi and Echinococcus canadensis. In this study, we obtained taeniid eggs from lion feces in Uganda and amplified DNA from individual eggs. Mitochondrial and nuclear DNA sequences showed similarities with those of other Echinococcus spp., but high values of percentage divergence of mitochondrial genes indicated the presence of a distinct species. In a second step, we compared this material with the preserved specimens of adult E. granulosus felidis, which had been identified morphologically approximately 40 years ago in South Africa. All DNA fragments (<200 bp) that could be amplified from the adults showed 100% similarity with the Ugandan material. In the phylogenetic tree of Echinococcus which was constructed from the mitochondrial genes, E. felidis is positioned as a sister taxon of E. granulosus sensu stricto. The data obtained will facilitate the development of diagnostic tools necessary to study the epidemiology of this enigmatic parasite.
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Biological features of a new Echinococcus species (Echinococcus shiquicus) in the east of Qinghai-Tibet Plateau
Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases, 2008Co-Authors: Ning Xiao, Minoru Nakao, Philip S Craig, Jiamin Qiu, Xingwang Chen, P.m. Schantz, Akira ItoAbstract:In the eastern Qinghai-Tibet Plateau region, a variety of domestic and wild mammals are involved in the transmission cycles of Echinococcus species. E. granulosus and E. multilocularis are known being sympatrically distributed in the plateau region. Recently, an unknown Echinococcus species was isolated from infected plateau pika (Ochotona curzoniae) and Tibetan fox (Vulpes ferrilata). The species shows quite distinct characteristics on morphology, genetics, host specificity and geographical distribution from others. It was therefore identified as a new Echinococcus species, Echinococcus shiquicus. This paper discussed the biological genetics and epidemiological features of the species, and proposed hypotheses and considerations for further exploration.
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Dual infection of animal hosts with different Echinococcus species in the eastern Qinghai-Tibet plateau region of China.
American Journal of Tropical Medicine and Hygiene, 2006Co-Authors: Ning Xiao, Minoru Nakao, Patrick Giraudoux, Philip S Craig, Jiamin Qiu, Christine M Budke, Akira ItoAbstract:The eastern Qinghai-Tibet plateau of China is a highly endemic region of echinococcosis where Echinococcus granulosus sensu stricto (sheep strain), Echinococcus multilocularis, and Echinococcus shiquicus are distributed sympatrically. We developed a polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method for the identification of the three species in this region. The PCR-RFLP showed the dual infection of animals with different Echinococcus spp. The first case was a domestic dog concurrently infected with adults of E. granulosus and E. multilocularis. The second case was a plateau pika (Ochotona curzoniae) harboring metacestodes of E. multilocularis and E. shiquicus in the liver. The high susceptibility of some mammalian hosts to the parasites and the high prevalence of the three co-endemic species probably increase the chance of mixed infections in the eastern Tibetan plateau.
R.c.a. Thompson - One of the best experts on this subject based on the ideXlab platform.
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Echinococcus as a model system: biology and epidemiology.
International journal for parasitology, 2014Co-Authors: R.c.a. Thompson, David JenkinsAbstract:The introduction of Echinococcus to Australia over 200 years ago and its establishment in sheep rearing areas of the country inflicted a serious medical and economic burden on the country. This resulted in an investment in both basic and applied research aimed at learning more about the biology and life cycle of Echinococcus. This research served to illustrate the uniqueness of the parasite in terms of developmental biology and ecology, and the value of Echinococcus as a model system in a broad range of research, from fundamental biology to theoretical control systems. These studies formed the foundation for an international, diverse and ongoing research effort on the hydatid organisms encompassing stem cell biology, gene regulation, strain variation, wildlife diseases and models of transmission dynamics. We describe the development, nature and diversity of this research, and how it was initiated in Australia but subsequently has stimulated much international and collaborative research on Echinococcus.
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Molecular and morphological characterization of Echinococcus in cervids from North America
Parasitology, 2005Co-Authors: R.c.a. Thompson, Annika Boxell, B. J. Ralston, C.c. Constantine, Russell P. Hobbs, Todd K. Shury, Merle E. OlsonAbstract: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.
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emergence re emergence of Echinococcus spp a global update
International Journal for Parasitology, 2005Co-Authors: David Jenkins, Thomas Romig, R.c.a. ThompsonAbstract:This review provides an update of the biological aspects of the genus Echinococcus and focuses on newly recognized endemic areas. Infection with the intermediate cystic stage of all species of Echinococcus causes disease and incapacity in animals and humans, and in the most serious cases, death of the host. Transmission of Echinococcus to new continents has occurred during European colonisation and the parasite has often taken advantage of Echinococcus-naive wildlife populations in these new environments, incorporating them into its transmission pattern. Echinococcus granulosus consists of a complex of 10 strains. Host specificities of these strains have important implications for transmission and control. As a result of human behaviour and/or political instability in a number of countries Echinococcus is re-emerging as an important public health issue. The importance of wildlife reservoirs in perpetuating transmission and as a source of infection for domestic animals and humans is addressed. The review also refers to the transmission pattern of a recently described new species, Echinococcus shiquicus, from China.
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Emergence/re-emergence of Echinococcus spp.—a global update
International Journal for Parasitology, 2005Co-Authors: David Jenkins, Thomas Romig, R.c.a. ThompsonAbstract:This review provides an update of the biological aspects of the genus Echinococcus and focuses on newly recognized endemic areas. Infection with the intermediate cystic stage of all species of Echinococcus causes disease and incapacity in animals and humans, and in the most serious cases, death of the host. Transmission of Echinococcus to new continents has occurred during European colonisation and the parasite has often taken advantage of Echinococcus-naive wildlife populations in these new environments, incorporating them into its transmission pattern. Echinococcus granulosus consists of a complex of 10 strains. Host specificities of these strains have important implications for transmission and control. As a result of human behaviour and/or political instability in a number of countries Echinococcus is re-emerging as an important public health issue. The importance of wildlife reservoirs in perpetuating transmission and as a source of infection for domestic animals and humans is addressed. The review also refers to the transmission pattern of a recently described new species, Echinococcus shiquicus, from China.
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Variation in Echinococcus: towards a taxonomic revision of the genus
Advances in parasitology, 1995Co-Authors: R.c.a. Thompson, Alan J. Lymbery, C.c. ConstantineAbstract:Publisher Summary Hydatid disease (echinococcosis) is one of the most important parasitic zoonoses and remains a public health and economic problem of global proportions. There are currently four recognized species in the genus Echinococcus : E.granulosus , E.multilocularis , E.oligarthrus , and E.vogeli . Because of the extensive variation in Echinococcus, it is very important to characterize the aetiological agents in different endemic areas to determine transmission patterns, particularly where there is the possibility of interaction between cycles. The first step in a taxonomic revision of the genus Echinococcus is to establish an appropriate species concept. Therefore, the purpose should be to update what is known about the nature and extent of variation in Echinococcus to provide a sound basis for a phylogenetic analysis. The current classification within the genus Echinococcus is not compatible with historical relationships between taxa. Phylogenetic analysis of DNA sequence data provides no support for the concept that E.grunulosus is a monophyletic group and it cannot be considered an evolutionary species. There is an urgent need for the molecular characterization of strains of E. multilocularis as well as strains of Echinococcus in lions and cervids, so that this taxonomic revision can be completed.
