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Guilherme G. Verocai - One of the best experts on this subject based on the ideXlab platform.
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A cryptic species of Onchocerca (Nematoda: Onchocercidae) in blackflies (Simulium spp.) from southern California, USA.
Parasites & vectors, 2018Co-Authors: Guilherme G. Verocai, Kimberly J. Nelson, R. Trey Callahan, Joseph Wakoli Wekesa, Hassan K. Hassan, Eric P. HobergAbstract:Entomological surveillance for pathogens based on molecular screening of putative arthropod vectors such as blackflies (Diptera: Simuliidae) is becoming increasingly important. Surveillance provides a means to understand host and geographical patterns of underestimated biodiversity among North American species of Onchocerca and a pathway to identify and track expanding emergence of the zoonotic Onchocerca lupi. Herein, we have screened two blackfly species, Simulium tescorum and Simulium vittatum (s.l.), from Los Angeles County, southern California, USA for DNA of filarioid nematodes to better understand species richness and limits within the genus Onchocerca. A total of 1056 and 378 female blackflies was collected using CO2-baited mosquito traps from March to November of 2015 and 2016, respectively. All blackflies during 2015 were individually processed for DNA extraction and PCR targeting of the cytochrome c oxidase subunit 1 (cox1) of the mitochondrial DNA (mtDNA). Specimens of S. tescorum collected in 2016 were processed individually with heads and bodies extracted separately, whereas those of S. vittatum (s.l.) were processed in pooled samples with heads and bodies extracted separately. A subset of filarioid-positive samples from 2015 and all samples from 2016 were screened using a PCR targeting the NADH dehydrogenase subunit 5 (nad5) gene (mtDNA). In 2015, 356 S. tescorum (33.7%) and 683 S. vittatum (s.l.) (64.7%) were collected, and an additional 17 specimens were not assessed morphologically. In 2016, a total of 378 blackflies was collected. Of these, 43 (11.6%) were S. tescorum and 327 (88.4%) were S. vittatum (s.l.), and an additional 8 specimens were not assessed morphologically. In 2015, Onchocerca sequences were detected in 4.8% (n = 17) of S. tescorum samples, and only one S. vittatum (0.15%). In 2016, only a single S. vittatum pool was positive for the same cryptic Onchocerca species. In phylogenetic comparisons based on nad5, the Onchocerca sequences from California formed a clade with those isolates in white-tailed deer from upstate New York, suggesting these belong to a single widespread cryptic species. An uncharacterized species of Onchocerca associated with cervid hosts was found in blackflies from southern California. Sequence data demonstrated it is likely conspecific with an unnamed species of Onchocerca previously found in white-tailed deer from upstate New York. Current data support recognition of a broad geographical distribution across North America for an apparently cryptic species of Onchocerca that is discrete from O. cervipedis, considered to be a typical filarioid among cervids. Our data suggest that this cryptic species of Onchocerca may infect subspecies of white-tailed deer (Odocoileus virginianus), and mule and black-tailed deer (Odocoileus hemionus) at temporal latitudes. The blackflies Simulium tescorum and S. vittatum (s.l.) (presumably, S. tribulatum) are putative vectors. Discovery of a cryptic complex indicates that species diversity and putative associations for definitive hosts and vectors of Onchocerca species in North America must be reassessed.
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A cryptic species of Onchocerca (Nematoda: Onchocercidae) in blackflies (Simulium spp.) from southern California, USA
Parasites & Vectors, 2018Co-Authors: Guilherme G. Verocai, Kimberly J. Nelson, R. Trey Callahan, Joseph Wakoli Wekesa, Hassan K. Hassan, Eric P. HobergAbstract:Background Entomological surveillance for pathogens based on molecular screening of putative arthropod vectors such as blackflies (Diptera: Simuliidae) is becoming increasingly important. Surveillance provides a means to understand host and geographical patterns of underestimated biodiversity among North American species of Onchocerca and a pathway to identify and track expanding emergence of the zoonotic Onchocerca lupi . Herein, we have screened two blackfly species, Simulium tescorum and Simulium vittatum ( s.l .), from Los Angeles County, southern California, USA for DNA of filarioid nematodes to better understand species richness and limits within the genus Onchocerca . Methods A total of 1056 and 378 female blackflies was collected using CO_2-baited mosquito traps from March to November of 2015 and 2016, respectively. All blackflies during 2015 were individually processed for DNA extraction and PCR targeting of the cytochrome c oxidase subunit 1 ( cox 1) of the mitochondrial DNA (mtDNA). Specimens of S. tescorum collected in 2016 were processed individually with heads and bodies extracted separately, whereas those of S. vittatum ( s.l .) were processed in pooled samples with heads and bodies extracted separately. A subset of filarioid-positive samples from 2015 and all samples from 2016 were screened using a PCR targeting the NADH dehydrogenase subunit 5 ( nad 5) gene (mtDNA). Results In 2015, 356 S. tescorum (33.7%) and 683 S. vittatum ( s.l .) (64.7%) were collected, and an additional 17 specimens were not assessed morphologically. In 2016, a total of 378 blackflies was collected. Of these, 43 (11.6%) were S. tescorum and 327 (88.4%) were S. vittatum ( s.l .), and an additional 8 specimens were not assessed morphologically. In 2015, Onchocerca sequences were detected in 4.8% ( n = 17) of S. tescorum samples, and only one S. vittatum (0.15%). In 2016, only a single S. vittatum pool was positive for the same cryptic Onchocerca species. In phylogenetic comparisons based on nad 5, the Onchocerca sequences from California formed a clade with those isolates in white-tailed deer from upstate New York, suggesting these belong to a single widespread cryptic species. Conclusions An uncharacterized species of Onchocerca associated with cervid hosts was found in blackflies from southern California. Sequence data demonstrated it is likely conspecific with an unnamed species of Onchocerca previously found in white-tailed deer from upstate New York. Current data support recognition of a broad geographical distribution across North America for an apparently cryptic species of Onchocerca that is discrete from O. cervipedis , considered to be a typical filarioid among cervids. Our data suggest that this cryptic species of Onchocerca may infect subspecies of white-tailed deer ( Odocoileus virginianus ), and mule and black-tailed deer ( Odocoileus hemionus ) at temporal latitudes. The blackflies Simulium tescorum and S. vittatum ( s.l .) (presumably, S. tribulatum ) are putative vectors. Discovery of a cryptic complex indicates that species diversity and putative associations for definitive hosts and vectors of Onchocerca species in North America must be reassessed.
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Whence river blindness? The domestication of mammals and host-parasite co-evolution in the nematode genus Onchocerca☆
International journal for parasitology, 2017Co-Authors: Emilie Lefoulon, Domenico Otranto, Alessio Giannelli, Benjamin L. Makepeace, Yasen Mutafchiev, Simon Townson, Shigehiko Uni, Guilherme G. Verocai, Coralie MartinAbstract:The genus Onchocerca includes 34 described species and represents one of the largest genera of the filarial nematodes within the family Onchocercidae. Representative members of this genus are mainly parasites of ungulates, with some exceptions such as Onchocerca lupi and Onchocerca volvulus, infecting carnivores and/or humans. For a long time, the evolutionary relationships amongst onchocercids remained poorly studied, as the systematics of this genus was impaired by the high morphological variability of species included in the taxon. Although some molecular phylogenies were developed, these studies were mainly focused on bovine Onchocerca spp. and O. volvulus, including assessments of Wolbachia endosymbionts. In the present study, we analysed 13 Onchocerca spp. from a larger host spectrum using a panel of seven different genes. Analysis of the coxI marker supports its usefulness for the identification of species within the genus. The evolutionary history of the genus has been herein revised by multi-gene phylogenies, presenting three strongly supported clades of Onchocerca spp. Analyses of co-evolutionary scenarios between Onchocerca and their vertebrate hosts underline the effect of domestication on Onchocerca speciation. Our study indicates that a host switch event occurred between Bovidae, Canidae and humans. Cophylogenetic analyses between Onchocerca and the endosymbiotic bacterium Wolbachia indicate the strongest co-evolutionary pattern ever registered within the filarial nematodes. Finally, this dataset indicates that the clade composed by O. lupi, Onchocerca gutturosa, Onchocerca lienalis, Onchocerca ochengi and O. volvulus derived from recent speciation.
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cryptic Onchocerca species infecting north american cervids with implications for the evolutionary history of host associations in Onchocerca
Parasitology, 2013Co-Authors: Quinn S Mcfrederick, Guilherme G. Verocai, Tamara S Haselkorn, John JaenikeAbstract:Parasites in the genus Onchocerca infect humans, ruminants, camels, horses, suids, and canids, with effects ranging from relatively benign to debilitating. In North America, Onchocerca cervipedis is the sole species known to infect cervids, while at least 5 Onchocerca species infect Eurasian cervids. In this study, we report the discovery of a cervid-parasitizing Onchocerca only distantly related to O. cervipedis . To reconstruct the phylogenetic history of the genus Onchocerca , we used newly acquired DNA sequence from O. cervipedis (from moose in Northwest Territories, Canada) and from the newly discovered species (from white-tailed deer in upstate New York), as well as previously published sequences. Ancestral host reconstructions suggest that host switches have been common throughout the evolutionary history of Onchocerca , and that bovid- and cervid-parasitizing species have been particularly important sources of descendant species. North America cervids might therefore serve as a source for Onchocerca invasions into new hosts. Given the high density of deer populations, the potential for zoonotic infections may also exist. Our discovery of a new Onchocerca species with relatively limited sampling suggests that the diversity of Onchocerca associated with cervids in North America may be greater than previously thought, and surveys utilizing molecules and morphology are necessary.
Eric P. Hoberg - One of the best experts on this subject based on the ideXlab platform.
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A cryptic species of Onchocerca (Nematoda: Onchocercidae) in blackflies (Simulium spp.) from southern California, USA.
Parasites & vectors, 2018Co-Authors: Guilherme G. Verocai, Kimberly J. Nelson, R. Trey Callahan, Joseph Wakoli Wekesa, Hassan K. Hassan, Eric P. HobergAbstract:Entomological surveillance for pathogens based on molecular screening of putative arthropod vectors such as blackflies (Diptera: Simuliidae) is becoming increasingly important. Surveillance provides a means to understand host and geographical patterns of underestimated biodiversity among North American species of Onchocerca and a pathway to identify and track expanding emergence of the zoonotic Onchocerca lupi. Herein, we have screened two blackfly species, Simulium tescorum and Simulium vittatum (s.l.), from Los Angeles County, southern California, USA for DNA of filarioid nematodes to better understand species richness and limits within the genus Onchocerca. A total of 1056 and 378 female blackflies was collected using CO2-baited mosquito traps from March to November of 2015 and 2016, respectively. All blackflies during 2015 were individually processed for DNA extraction and PCR targeting of the cytochrome c oxidase subunit 1 (cox1) of the mitochondrial DNA (mtDNA). Specimens of S. tescorum collected in 2016 were processed individually with heads and bodies extracted separately, whereas those of S. vittatum (s.l.) were processed in pooled samples with heads and bodies extracted separately. A subset of filarioid-positive samples from 2015 and all samples from 2016 were screened using a PCR targeting the NADH dehydrogenase subunit 5 (nad5) gene (mtDNA). In 2015, 356 S. tescorum (33.7%) and 683 S. vittatum (s.l.) (64.7%) were collected, and an additional 17 specimens were not assessed morphologically. In 2016, a total of 378 blackflies was collected. Of these, 43 (11.6%) were S. tescorum and 327 (88.4%) were S. vittatum (s.l.), and an additional 8 specimens were not assessed morphologically. In 2015, Onchocerca sequences were detected in 4.8% (n = 17) of S. tescorum samples, and only one S. vittatum (0.15%). In 2016, only a single S. vittatum pool was positive for the same cryptic Onchocerca species. In phylogenetic comparisons based on nad5, the Onchocerca sequences from California formed a clade with those isolates in white-tailed deer from upstate New York, suggesting these belong to a single widespread cryptic species. An uncharacterized species of Onchocerca associated with cervid hosts was found in blackflies from southern California. Sequence data demonstrated it is likely conspecific with an unnamed species of Onchocerca previously found in white-tailed deer from upstate New York. Current data support recognition of a broad geographical distribution across North America for an apparently cryptic species of Onchocerca that is discrete from O. cervipedis, considered to be a typical filarioid among cervids. Our data suggest that this cryptic species of Onchocerca may infect subspecies of white-tailed deer (Odocoileus virginianus), and mule and black-tailed deer (Odocoileus hemionus) at temporal latitudes. The blackflies Simulium tescorum and S. vittatum (s.l.) (presumably, S. tribulatum) are putative vectors. Discovery of a cryptic complex indicates that species diversity and putative associations for definitive hosts and vectors of Onchocerca species in North America must be reassessed.
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A cryptic species of Onchocerca (Nematoda: Onchocercidae) in blackflies (Simulium spp.) from southern California, USA
Parasites & Vectors, 2018Co-Authors: Guilherme G. Verocai, Kimberly J. Nelson, R. Trey Callahan, Joseph Wakoli Wekesa, Hassan K. Hassan, Eric P. HobergAbstract:Background Entomological surveillance for pathogens based on molecular screening of putative arthropod vectors such as blackflies (Diptera: Simuliidae) is becoming increasingly important. Surveillance provides a means to understand host and geographical patterns of underestimated biodiversity among North American species of Onchocerca and a pathway to identify and track expanding emergence of the zoonotic Onchocerca lupi . Herein, we have screened two blackfly species, Simulium tescorum and Simulium vittatum ( s.l .), from Los Angeles County, southern California, USA for DNA of filarioid nematodes to better understand species richness and limits within the genus Onchocerca . Methods A total of 1056 and 378 female blackflies was collected using CO_2-baited mosquito traps from March to November of 2015 and 2016, respectively. All blackflies during 2015 were individually processed for DNA extraction and PCR targeting of the cytochrome c oxidase subunit 1 ( cox 1) of the mitochondrial DNA (mtDNA). Specimens of S. tescorum collected in 2016 were processed individually with heads and bodies extracted separately, whereas those of S. vittatum ( s.l .) were processed in pooled samples with heads and bodies extracted separately. A subset of filarioid-positive samples from 2015 and all samples from 2016 were screened using a PCR targeting the NADH dehydrogenase subunit 5 ( nad 5) gene (mtDNA). Results In 2015, 356 S. tescorum (33.7%) and 683 S. vittatum ( s.l .) (64.7%) were collected, and an additional 17 specimens were not assessed morphologically. In 2016, a total of 378 blackflies was collected. Of these, 43 (11.6%) were S. tescorum and 327 (88.4%) were S. vittatum ( s.l .), and an additional 8 specimens were not assessed morphologically. In 2015, Onchocerca sequences were detected in 4.8% ( n = 17) of S. tescorum samples, and only one S. vittatum (0.15%). In 2016, only a single S. vittatum pool was positive for the same cryptic Onchocerca species. In phylogenetic comparisons based on nad 5, the Onchocerca sequences from California formed a clade with those isolates in white-tailed deer from upstate New York, suggesting these belong to a single widespread cryptic species. Conclusions An uncharacterized species of Onchocerca associated with cervid hosts was found in blackflies from southern California. Sequence data demonstrated it is likely conspecific with an unnamed species of Onchocerca previously found in white-tailed deer from upstate New York. Current data support recognition of a broad geographical distribution across North America for an apparently cryptic species of Onchocerca that is discrete from O. cervipedis , considered to be a typical filarioid among cervids. Our data suggest that this cryptic species of Onchocerca may infect subspecies of white-tailed deer ( Odocoileus virginianus ), and mule and black-tailed deer ( Odocoileus hemionus ) at temporal latitudes. The blackflies Simulium tescorum and S. vittatum ( s.l .) (presumably, S. tribulatum ) are putative vectors. Discovery of a cryptic complex indicates that species diversity and putative associations for definitive hosts and vectors of Onchocerca species in North America must be reassessed.
Hiroyuki Takaoka - One of the best experts on this subject based on the ideXlab platform.
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blackfly vectors of zoonotic onchocerciasis in japan
Medical and Veterinary Entomology, 2012Co-Authors: Shigehiko Uni, Hiroyuki Takaoka, Masako Fukuda, Yasushi Otsuka, Chiharu Aoki, O BainAbstract:Studies of blackfly vectors of Onchocerca dewittei japonica Uni, Bain & Takaoka (Spirurida: Onchocercidae), a parasite of wild boar implicated in the aetiology of zoonotic onchocerciasis in Japan, and six other zoonotic Onchocerca species of this country are reviewed. Molecular identification of infective larvae found in wild-caught female blackflies showed that Simulium bidentatum (Shiraki) (Diptera: Simuliidae) is a natural vector of O. dewittei japonica, and also Onchocerca sp. sensu Fukuda et al., another parasite of wild boar. Inoculation experiments demonstrated that Simulium arakawae Matsumura and four other Simulium species are putative vectors. Similarly, S. arakawae, S. bidentatum and Simulium oitanum (Shiraki) are putative vectors of Onchocerca eberhardi Uni & Bain and Onchocerca skrjabini Rukhlyadev, parasites of sika deer. Morphometric studies of infective larvae indicated that Onchocerca lienalis Stiles, a bovine species, is transmitted by S. arakawae, Simulium daisense (Takahasi) and Simulium kyushuense Takaoka, and that Onchocerca sp. sensu Takaoka & Bain, another bovine species, is transmitted by S. arakawae, S. bidentatum, S. daisense and S. oitanum. Prosimulium sp. (Diptera: Simuliidae) and Simulium japonicum Matsumura are suspected vectors of Onchocerca suzukii Yagi, Bain & Shoho and O. skrjabini [Twinnia japonensis Rubtsov (Diptera: Simuliidae) may also transmit the latter], parasites of Japanese serow, following detection of the parasites' DNA genes in wild-caught blackflies.
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molecular identification of infective larvae of three species of Onchocerca found in wild caught females of simulium bidentatum in japan
Parasite, 2010Co-Authors: Masako Fukuda, Shigehiko Uni, Yasushi Otsuka, O Bain, Hiroyuki TakaokaAbstract:Wild female black flies attracted to a man or an idling automobile were collected at Oita, Japan where five cases of zoonotic onchocerciasis had occurred. Among the five Simulium species captured, 2% of Simulium bidentatum , the predominant species, were infected with filarial larvae. There were at least two types of infective larvae, types A and B, based on morphometric observation. Moreover, molecular analysis of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene revealed that types A and B were represented by a single unknown species of Onchocerca and two species, i.e ., Onchocerca dewittei japonica from wild boar, the causative agent of zoonotic onchocerciasis in Japan, and an undescribed Onchocerca sp. from wild boar, respectively. Phylogenetic analysis based on the sequences of the mitochondrial 12S ribosomal RNA (12S rRNA) gene also showed that type A is likely to be an unknown species of Onchocerca . Natural infection of black flies with infective larvae of O . dewittei japonica and O. sp. was demonstrated for the first time. The present study strongly suggests that S . bidentatum plays a role as a vector in the transmission of zoonotic onchocerciasis due to O . dewittei japonica in Japan.
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natural vectors of three bovine Onchocerca species nematoda onchocercidae and seasonal transmission by three blackfly species diptera simuliidae in central kyushu japan
Journal of Medical Entomology, 1994Co-Authors: Hiroyuki TakaokaAbstract:Eleven blackfly species were examined in relation to the transmission of bovine onchocerciasis in central Kyushu, Japan. A total of 19,005 out of 47,746 females captured from June 1989 to June 1990 at two cattle sheds each in Oita and Kumamoto were dissected for their parities, infections with Onchocerca larvae, and intakes of Onchocerca microfilariae. Overall results showed that Simulium bidentatum (Shiraki), the predominant species, is a natural vector of the two bovine Onchocerca species, i.e., type I ( O . sp.) in both localities and type II (probably O. gutturosa Neumann), in Oita, whereas S. kyushuense Takaoka and S. arakawae Matsumura serve as the primary vector of type III ( O. lienalis Stiles) in Kumamoto and Oita, respectively. Simulium arakawae also plays a secondary role in the transmission of type I in Oita and of type III in Kumamoto. Despite the biting activities and microfilarial intakes observed throughout most of the entire year, the transmission of these bovine Onchocerca was restricted to the mild or warm months between May and November. The natural infections with mermithid, trematode, ciliates, and fungi occurred but their influence on the vector Simulium species was apparently small, if at all.
O Bain - One of the best experts on this subject based on the ideXlab platform.
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Onchocerca takaokai n sp nematoda filarioidea in japanese wild boars sus scrofa leucomystax description and molecular identification of intradermal females
Parasitology International, 2015Co-Authors: Shigehiko Uni, Masako Fukuda, Yasushi Otsuka, O Bain, Takeshi Agatsuma, Jun Nakatani, Makoto Matsubayashi, Masashi Harada, Hasmahzaiti OmarAbstract:Human zoonotic onchocercosis is caused by Onchocerca dewittei japonica, parasitic in wild boars (Sus scrofa leucomystax) in Japan. Previously, microfilariae longer than those of Onchocerca dewittei japonica were observed in skin snips from wild boars during the study of O. dewittei japonica. Moreover, the third-stage larvae (L3) of these longer microfilariae were obtained from the blackfly Simulium bidentatum after experimental injections. Based on morphometric and molecular studies, similar L3 were found in blackflies during fieldwork in Oita, Japan. However, except for O. dewittei japonica, adult worms of Onchocerca have not been found in wild boars. In this study, we discovered adult females of a novel Onchocerca species in the skin of a wild boar in Oita, and named it Onchocerca takaokai n. sp. Females of this new species had longer microfilariae and differed from O. dewittei japonica in terms of their morphological characteristics and parasitic location. The molecular characteristics of the cytochrome c oxidase subunit 1 and 12S rRNA genes of the new species were identical to those of the longer microfilariae and L3 previously detected, but they differed from those of O. dewittei japonica at the species level. However, both species indicated a close affinity among their congeners and Onchocerca ramachandrini, parasitic in the warthog in Africa, was basal in the Suidae cluster of the 12S rRNA tree.
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blackfly vectors of zoonotic onchocerciasis in japan
Medical and Veterinary Entomology, 2012Co-Authors: Shigehiko Uni, Hiroyuki Takaoka, Masako Fukuda, Yasushi Otsuka, Chiharu Aoki, O BainAbstract:Studies of blackfly vectors of Onchocerca dewittei japonica Uni, Bain & Takaoka (Spirurida: Onchocercidae), a parasite of wild boar implicated in the aetiology of zoonotic onchocerciasis in Japan, and six other zoonotic Onchocerca species of this country are reviewed. Molecular identification of infective larvae found in wild-caught female blackflies showed that Simulium bidentatum (Shiraki) (Diptera: Simuliidae) is a natural vector of O. dewittei japonica, and also Onchocerca sp. sensu Fukuda et al., another parasite of wild boar. Inoculation experiments demonstrated that Simulium arakawae Matsumura and four other Simulium species are putative vectors. Similarly, S. arakawae, S. bidentatum and Simulium oitanum (Shiraki) are putative vectors of Onchocerca eberhardi Uni & Bain and Onchocerca skrjabini Rukhlyadev, parasites of sika deer. Morphometric studies of infective larvae indicated that Onchocerca lienalis Stiles, a bovine species, is transmitted by S. arakawae, Simulium daisense (Takahasi) and Simulium kyushuense Takaoka, and that Onchocerca sp. sensu Takaoka & Bain, another bovine species, is transmitted by S. arakawae, S. bidentatum, S. daisense and S. oitanum. Prosimulium sp. (Diptera: Simuliidae) and Simulium japonicum Matsumura are suspected vectors of Onchocerca suzukii Yagi, Bain & Shoho and O. skrjabini [Twinnia japonensis Rubtsov (Diptera: Simuliidae) may also transmit the latter], parasites of Japanese serow, following detection of the parasites' DNA genes in wild-caught blackflies.
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human ocular filariasis further evidence on the zoonotic role of Onchocerca lupi
Parasites & Vectors, 2012Co-Authors: Domenico Otranto, Yasen Mutafchiev, Filipe Dantastorres, Zafer Cebeci, Baris Yeniad, Nesimi Buyukbabani, Ozden Boral, Andrea Gustinelli, Trimeche Mounir, O BainAbstract:Background Among ocular vector-borne pathogens, Onchocerca volvulus, the agent of the so-called “river blindness”, affects about 37 million people globally. Other Onchocerca spp. have been sporadically reported as zoonotic agents. Cases of canine onchocerciasis caused by Onchocerca lupi are on the rise in the United States and Europe. Its zoonotic role has been suspected but only recently ascertained in a single case from Turkey. The present study provides further evidence on the occurrence of O. lupi infesting human eyes in two patients from Turkey (case 1) and Tunisia (case 2). The importance of obtaining a correct sample collection and preparation of nematodes infesting human eyes is highlighted.
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molecular identification of infective larvae of three species of Onchocerca found in wild caught females of simulium bidentatum in japan
Parasite, 2010Co-Authors: Masako Fukuda, Shigehiko Uni, Yasushi Otsuka, O Bain, Hiroyuki TakaokaAbstract:Wild female black flies attracted to a man or an idling automobile were collected at Oita, Japan where five cases of zoonotic onchocerciasis had occurred. Among the five Simulium species captured, 2% of Simulium bidentatum , the predominant species, were infected with filarial larvae. There were at least two types of infective larvae, types A and B, based on morphometric observation. Moreover, molecular analysis of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene revealed that types A and B were represented by a single unknown species of Onchocerca and two species, i.e ., Onchocerca dewittei japonica from wild boar, the causative agent of zoonotic onchocerciasis in Japan, and an undescribed Onchocerca sp. from wild boar, respectively. Phylogenetic analysis based on the sequences of the mitochondrial 12S ribosomal RNA (12S rRNA) gene also showed that type A is likely to be an unknown species of Onchocerca . Natural infection of black flies with infective larvae of O . dewittei japonica and O. sp. was demonstrated for the first time. The present study strongly suggests that S . bidentatum plays a role as a vector in the transmission of zoonotic onchocerciasis due to O . dewittei japonica in Japan.
Benjamin L. Makepeace - One of the best experts on this subject based on the ideXlab platform.
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Whence river blindness? The domestication of mammals and host-parasite co-evolution in the nematode genus Onchocerca☆
International journal for parasitology, 2017Co-Authors: Emilie Lefoulon, Domenico Otranto, Alessio Giannelli, Benjamin L. Makepeace, Yasen Mutafchiev, Simon Townson, Shigehiko Uni, Guilherme G. Verocai, Coralie MartinAbstract:The genus Onchocerca includes 34 described species and represents one of the largest genera of the filarial nematodes within the family Onchocercidae. Representative members of this genus are mainly parasites of ungulates, with some exceptions such as Onchocerca lupi and Onchocerca volvulus, infecting carnivores and/or humans. For a long time, the evolutionary relationships amongst onchocercids remained poorly studied, as the systematics of this genus was impaired by the high morphological variability of species included in the taxon. Although some molecular phylogenies were developed, these studies were mainly focused on bovine Onchocerca spp. and O. volvulus, including assessments of Wolbachia endosymbionts. In the present study, we analysed 13 Onchocerca spp. from a larger host spectrum using a panel of seven different genes. Analysis of the coxI marker supports its usefulness for the identification of species within the genus. The evolutionary history of the genus has been herein revised by multi-gene phylogenies, presenting three strongly supported clades of Onchocerca spp. Analyses of co-evolutionary scenarios between Onchocerca and their vertebrate hosts underline the effect of domestication on Onchocerca speciation. Our study indicates that a host switch event occurred between Bovidae, Canidae and humans. Cophylogenetic analyses between Onchocerca and the endosymbiotic bacterium Wolbachia indicate the strongest co-evolutionary pattern ever registered within the filarial nematodes. Finally, this dataset indicates that the clade composed by O. lupi, Onchocerca gutturosa, Onchocerca lienalis, Onchocerca ochengi and O. volvulus derived from recent speciation.
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25 Years of the Onchocerca ochengi Model
Trends in parasitology, 2016Co-Authors: Benjamin L. Makepeace, Vincent N. TanyaAbstract:Although of limited veterinary significance, Onchocerca ochengi has become famous as a natural model or ‘analogue' of human onchocerciasis (river blindness), which is caused by Onchocerca volvulus . On the basis of both morphological and molecular criteria, O. ochengi is the closest extant relative of O. volvulus and shares several key natural history traits with the human pathogen. These include exploitation of the same group of insect vectors (blackflies of the Simulium damnosum complex) and formation of collagenous nodules with a similar histological structure to human nodules. Here, we review the contribution of this natural system to drug and vaccine discovery efforts, as well as to our basic biological understanding of Onchocerca spp., over the past quarter-century.
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Onchocerca armillata contains the endosymbiotic bacterium Wolbachia and elicits a limited inflammatory response.
Veterinary parasitology, 2010Co-Authors: Joseph M. Neary, Udo Hetzel, Alexander J. Trees, David Ekale, Vincent N. Tanya, Benjamin L. MakepeaceAbstract:Human onchocerciasis, also known as River Blindness, is a debilitating disease caused by the filarial nematode Onchocerca volvulus. Many, but not all, filarial nematodes carry within their tissues endosymbiotic, Rickettsia-like bacteria of the genus Wolbachia. Onchocerca spp. infections in cattle offer the most relevant, analogous host-parasite model system. West African cattle are commonly co-infected with four Onchocerca spp.; two of these are Wolbachia-positive (Onchocerca gutturosa and Onchocerca ochengi), and the remainder are of unknown Wolbachia status (Onchocerca dukei and Onchocerca armillata). Previous studies have suggested that worm survival is dependent on this bacterium. O. armillata, an abundant parasite of African cattle that has received little attention, is a primitive species that may lack Wolbachia. The objectives of this study were to determine if O. armillata carries Wolbachia and to provide preliminary descriptions of the host inflammatory cell environment around the adult worms. The findings may support or refute the hypothesis that a prime contribution of Wolbachia is to permit long-term survival and reproduction of certain Onchocerca spp. (including O. volvulus in humans). O. armillata adult worms were found in the aorta of 90.7% of cattle (n=54) slaughtered at an abattoir in Ngaoundéré, Adamawa Region, Cameroon. The presence of Wolbachia in O. armillata was confirmed by a specific anti-Wolbachia surface protein antibody detected using a peroxidase conjugate (immunohistochemistry) and PCR for detection of Wolbachia-specific sequences within DNA extracts from frozen worms. Tissue sections stained with haematoxylin and eosin showed the host cell response to be dominated by macrophages and fibroblasts. This is unusual compared with nodule-dwelling Wolbachia-positive Onchocerca spp., where the host response is typically characterised by granulocytes, and suggests that the mechanisms for worm survival employed by this species (which is probably motile) may differ.
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Onchocerca armillata contains the endosymbiotic bacterium Wolbachia and elicits a limited inflammatory response
Veterinary Parasitology, 2010Co-Authors: Joseph M. Neary, Udo Hetzel, Alexander J. Trees, David Ekale, Vincent N. Tanya, Benjamin L. MakepeaceAbstract:Human onchocerciasis, also known as River Blindness, is a debilitating disease caused by the filarial nematode Onchocerca volvulus. Many, but not all, filarial nematodes carry within their tissues endosymbiotic, Rickettsia-like bacteria of the genus Wolbachia. Onchocerca spp. infections in cattle offer the most relevant, analogous host–parasite model system. West African cattle are commonly co-infected with four Onchocerca spp.; two of these are Wolbachia-positive (Onchocerca gutturosa and Onchocerca ochengi), and the remainder are of unknown Wolbachia status (Onchocerca dukei and Onchocerca armillata). Previous studies have suggested that worm survival is dependent on this bacterium. O. armillata, an abundant parasite of African cattle that has received little attention, is a primitive species that may lack Wolbachia. The objectives of this study were to determine if O. armillata carries Wolbachia and to provide preliminary descriptions of the host inflammatory cell environment around the adult worms. The findings may support or refute the hypothesis that a prime contribution of Wolbachia is to permit long-term survival and reproduction of certain Onchocerca spp. (including O. volvulus in humans). O. armillata adult worms were found in the aorta of 90.7% of cattle (n = 54) slaughtered at an abattoir in Ngaoundere, Adamawa Region, Cameroon. The presence of Wolbachia in O. armillata was confirmed by a specific anti-Wolbachia surface protein antibody detected using a peroxidase conjugate (immunohistochemistry) and PCR for detection of Wolbachia-specific sequences within DNA extracts from frozen worms. Tissue sections stained with haematoxylin and eosin showed the host cell response to be dominated by macrophages and fibroblasts. This is unusual compared with nodule-dwelling Wolbachia-positive Onchocerca spp., where the host response is typically characterised by granulocytes, and suggests that the mechanisms for worm survival employed by this species (which is probably motile) may differ.
