Pub Date : 2024-09-26DOI: 10.1016/j.ijpara.2024.09.004
Frédéric Douhard, Xavier Matthey, Didier Marcon, Camille Coffre-Thomain, Lucie Estivalet, Delphine Serreau, Fabrice Guégnard, Guillaume Sallé, Papa Moussa Drame, Frédéric Elleboudt, François Lecompte, Hans Adriaensen
Although benefits of selection for host resistance to gastro-intestinal nematodes have long been recognized, its costs on production traits remain unclear. A main difficulty when studying those costs is to disentangle genetic effects due to selection from plastic responses induced by infection. Putative costs of host resistance have been extensively investigated in growing sheep. However, while most of those studies have relied on live weight to assess body growth, more comprehensive assessments accounting for body composition are advocated to detect trade-offs. In this study we used 90 female lambs from lines divergently selected on resistance to Haemonchus contortus that we experimentally infected (n = 60) or not (n = 30) under controlled conditions. As those conditions were defined to enable uninfected lambs to fully express their growth potential, we sought to precisely identify the effects of selection for host resistance on health traits and on growth traits. We assessed muscular and fat growth based on repeated measurements with dorsal ultrasonography for all lambs on farm, and with whole-body computed tomography (CT) scans for a subgroup of 18 infected lambs. Lambs achieved a high growth rate, including infected ones despite their high worm burden (confirmed at necropsy in the subgroup). As expected, lambs from the resistant (R) line were less infected than those from the susceptible (S) line. However, the clear pathogenic effects observed on muscular growth and voluntary feed intake were similar between lines. In contrast, a line difference in body fat was supported both by dorsal and volumetric CT measurements. Specifically, lower fat in the R line compared with the S line was observed equally in infected and uninfected groups, thus providing evidence for a constitutive cost of host resistance. Although this cost is not necessarily disadvantageous in nutrient-rich environments exposing animals to excess fat deposition, its consequences in nutrient-scarce environments may be important to promote sustainable breeding strategies for host resistance.
{"title":"Evidence for a constitutive cost of host resistance on body fat growth in ewe lambs from lines selected for resistance or susceptibility to experimental infections with Haemonchus contortus.","authors":"Frédéric Douhard, Xavier Matthey, Didier Marcon, Camille Coffre-Thomain, Lucie Estivalet, Delphine Serreau, Fabrice Guégnard, Guillaume Sallé, Papa Moussa Drame, Frédéric Elleboudt, François Lecompte, Hans Adriaensen","doi":"10.1016/j.ijpara.2024.09.004","DOIUrl":"10.1016/j.ijpara.2024.09.004","url":null,"abstract":"<p><p>Although benefits of selection for host resistance to gastro-intestinal nematodes have long been recognized, its costs on production traits remain unclear. A main difficulty when studying those costs is to disentangle genetic effects due to selection from plastic responses induced by infection. Putative costs of host resistance have been extensively investigated in growing sheep. However, while most of those studies have relied on live weight to assess body growth, more comprehensive assessments accounting for body composition are advocated to detect trade-offs. In this study we used 90 female lambs from lines divergently selected on resistance to Haemonchus contortus that we experimentally infected (n = 60) or not (n = 30) under controlled conditions. As those conditions were defined to enable uninfected lambs to fully express their growth potential, we sought to precisely identify the effects of selection for host resistance on health traits and on growth traits. We assessed muscular and fat growth based on repeated measurements with dorsal ultrasonography for all lambs on farm, and with whole-body computed tomography (CT) scans for a subgroup of 18 infected lambs. Lambs achieved a high growth rate, including infected ones despite their high worm burden (confirmed at necropsy in the subgroup). As expected, lambs from the resistant (R) line were less infected than those from the susceptible (S) line. However, the clear pathogenic effects observed on muscular growth and voluntary feed intake were similar between lines. In contrast, a line difference in body fat was supported both by dorsal and volumetric CT measurements. Specifically, lower fat in the R line compared with the S line was observed equally in infected and uninfected groups, thus providing evidence for a constitutive cost of host resistance. Although this cost is not necessarily disadvantageous in nutrient-rich environments exposing animals to excess fat deposition, its consequences in nutrient-scarce environments may be important to promote sustainable breeding strategies for host resistance.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-25DOI: 10.1016/j.ijpara.2024.09.002
Verónica Taglioretti, María Alejandra Rossin, Eugenia Levy, Juan Tomás Timi
Parasites can provide suitable models for studying β-diversity due to their strict dependence on both the environment and the biology and distribution of their hosts, aiding in the interpretation of any patterns that hosts can display. With the aim of quantifying the relative importance of host features, environmental factors and spatial distances as drivers of fish parasite β-diversity along a unidirectional gradient, the structure of fish parasite assemblages was analysed using generalised dissimilarity models (GDMs). A total of 150 poeciliid fish were examined for larval trematodes, recording host features and physical parameters of each sampling site along the stream. Differences among digenean communities increased when Strahler order changed along the stream, associated with increasing species richness and abundance downstream. Environmental gradient, spatial distance and host features were identified as significant determining factors of species turnover, with conductivity being the most important, followed by spatial distance. In the present study, environmental variables were spatially structured along the stream, their effects as structurers of parasite β-diversity being higher than the pure environmental or the pure distance effect. Such predominance prevents us from establishing at what point on the continuum from niche to neutrality these communities are located. Results from the present research contribute to improving our knowledge of the factors that shape parasite community changes, and underline the importance of considering the pure and shared effects of spatial, environmental and host feature factors in order to determine the real contribution of each one as a determinant of parasite β- diversity.
{"title":"Parasite β-diversity along a stream: effect of distance and environment.","authors":"Verónica Taglioretti, María Alejandra Rossin, Eugenia Levy, Juan Tomás Timi","doi":"10.1016/j.ijpara.2024.09.002","DOIUrl":"10.1016/j.ijpara.2024.09.002","url":null,"abstract":"<p><p>Parasites can provide suitable models for studying β-diversity due to their strict dependence on both the environment and the biology and distribution of their hosts, aiding in the interpretation of any patterns that hosts can display. With the aim of quantifying the relative importance of host features, environmental factors and spatial distances as drivers of fish parasite β-diversity along a unidirectional gradient, the structure of fish parasite assemblages was analysed using generalised dissimilarity models (GDMs). A total of 150 poeciliid fish were examined for larval trematodes, recording host features and physical parameters of each sampling site along the stream. Differences among digenean communities increased when Strahler order changed along the stream, associated with increasing species richness and abundance downstream. Environmental gradient, spatial distance and host features were identified as significant determining factors of species turnover, with conductivity being the most important, followed by spatial distance. In the present study, environmental variables were spatially structured along the stream, their effects as structurers of parasite β-diversity being higher than the pure environmental or the pure distance effect. Such predominance prevents us from establishing at what point on the continuum from niche to neutrality these communities are located. Results from the present research contribute to improving our knowledge of the factors that shape parasite community changes, and underline the importance of considering the pure and shared effects of spatial, environmental and host feature factors in order to determine the real contribution of each one as a determinant of parasite β- diversity.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.ijpara.2024.09.003
O Alejandro Aleuy, Leslie W Woods, Benjamin J Padilla, Dennis Richardson, Juliann T Schamel, Stacy Baker, Martín García-Varela, Charlotte Hammond, Sarah P Lawson, Jasmine N Childress, Jason Rohr, Kevin D Lafferty
In the late 1990s, the San Miguel Island fox (Urocyon littoralis littoralis) faced near-extinction. Fourteen of the 15 remaining foxes were placed into an island-based captive breeding program used to repopulate the island. Although the fox population in San Miguel reached pre-decline numbers by 2010, a second decline started around 2014, coincidental with a newly observed acanthocephalan parasite. To identify this introduced acanthocephalan species and determine the pathologic consequences of its infection on the health of foxes, we used an extensive record of island fox necropsies and associated parasite collections. In addition, we used detailed fox capture-recapture data to investigate population health and demographic trends of foxes before and after parasite emergence. We identify the parasite as Pachysentis canicola, a common acanthocephalan in mainland foxes in North America. The parasite was detected in 69% of the necropsied foxes from San Miguel Island and was not found in any of the other five Channel Island fox subspecies. Health impacts attributed to the acanthocephalan parasite, including erosive and ulcerative enteritis, transmural necrosis, and inflammation, were described in 47% of the foxes infected with the acanthocephalan. Despite infection with various other helminth parasite species, body condition remained good and the mortality rate low in San Miguel Island foxes until the arrival of the acanthocephalan. Body condition improved after 2018, perhaps due to increases in rainfall following a drought, but remained 27% lower than the pre-acanthocephalan period, which suggests that environmental conditions and parasitism jointly drive fox population dynamics.
{"title":"The invasive acanthocephalan parasite Pachysentis canicola is associated with a declining endemic island fox population on San Miguel Island.","authors":"O Alejandro Aleuy, Leslie W Woods, Benjamin J Padilla, Dennis Richardson, Juliann T Schamel, Stacy Baker, Martín García-Varela, Charlotte Hammond, Sarah P Lawson, Jasmine N Childress, Jason Rohr, Kevin D Lafferty","doi":"10.1016/j.ijpara.2024.09.003","DOIUrl":"10.1016/j.ijpara.2024.09.003","url":null,"abstract":"<p><p>In the late 1990s, the San Miguel Island fox (Urocyon littoralis littoralis) faced near-extinction. Fourteen of the 15 remaining foxes were placed into an island-based captive breeding program used to repopulate the island. Although the fox population in San Miguel reached pre-decline numbers by 2010, a second decline started around 2014, coincidental with a newly observed acanthocephalan parasite. To identify this introduced acanthocephalan species and determine the pathologic consequences of its infection on the health of foxes, we used an extensive record of island fox necropsies and associated parasite collections. In addition, we used detailed fox capture-recapture data to investigate population health and demographic trends of foxes before and after parasite emergence. We identify the parasite as Pachysentis canicola, a common acanthocephalan in mainland foxes in North America. The parasite was detected in 69% of the necropsied foxes from San Miguel Island and was not found in any of the other five Channel Island fox subspecies. Health impacts attributed to the acanthocephalan parasite, including erosive and ulcerative enteritis, transmural necrosis, and inflammation, were described in 47% of the foxes infected with the acanthocephalan. Despite infection with various other helminth parasite species, body condition remained good and the mortality rate low in San Miguel Island foxes until the arrival of the acanthocephalan. Body condition improved after 2018, perhaps due to increases in rainfall following a drought, but remained 27% lower than the pre-acanthocephalan period, which suggests that environmental conditions and parasitism jointly drive fox population dynamics.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1016/j.ijpara.2024.09.001
Madalene M Giannotta, Ina Smith, Michelle Michie, Kim Blasdell, Mike Dunn, James Nicholls, Allen C G Heath, Juanita Rodriguez, Alexander W Gofton
Ticks are important medical and veterinary parasites that represent a substantial health threat to humans, companion animals, and livestock. Ixodiphagus wasps (Hymenoptera; Encyrtidae) are known endoparasitoids of ixodid (hard) and argasid (soft) ticks, with potential utility as natural biocontrol agents. Two species, Ixodiphagus brunneus and Ixodiphagus mysorensis, are previously recorded from Australia, however, the genus lacks formal revisionary work in Australia, and the validity and host ranges of these species remain uncertain. This work aimed to investigate the diversity of Ixodiphagus in Australasia and provide a molecular data resource for future work on these understudied endoparasitoids. We extracted DNA from archival Ixodiphagus specimens from Australian and New Zealand insect collections and performed high-throughput sequencing which resulted in complete or mostly complete mitochondrial genome sequences from 11 specimens, including I. brunneus, Ixodiphagus taiaroaensis, and a novel Ixodiphagus sp. reared from Rhipicephalus linnaei from Townsville, Australia. In addition, approximately 70% of the genome of the Wolbachia endosymbiont of I. brunneus was recovered. Finally, we screened 178 recently collected pooled tick samples from southern New South Wales, Australia, for Ixodiphagus spp. using 28S rRNA and cytochrome c oxidase subunit 1(COI) gene PCR, and recovered 14 positive samples. Phylogenetic analysis of Australasian Ixodiphagus spp. based on 28S rRNA and complete mitochondrial genome sequences determined that members of the Australasian fauna are distinct from Ixodiphagus hookeri (the only other Ixodiphagus species for which genetic data exists), and that at least two distinct species are present in Australia; I. brunneus identified from Ixodes holocyclus and Haemaphysalis bancrofti ticks, and an uncharacterised Ixodiphagus sp. found in Rhipicephalus linnaei ticks from northern Queensland. Furthermore, there was substantial genetic diversity at the 28S rRNA loci among I. brunneus samples, which may represent normal genetic variability or a secondary cryptic species. The molecular data generated here represents the first known for the genus Ixodiphagus in Australasia, doubling that of the world fauna, and provides the first known complete mitochondrial genomes for these important tick parasitoids.
{"title":"Molecular characterisation of Australasian Ixodiphagus (Hymenoptera; Encyrtidae; Encyrtinae) reveals unexpected diversity and a potential novel host switch.","authors":"Madalene M Giannotta, Ina Smith, Michelle Michie, Kim Blasdell, Mike Dunn, James Nicholls, Allen C G Heath, Juanita Rodriguez, Alexander W Gofton","doi":"10.1016/j.ijpara.2024.09.001","DOIUrl":"https://doi.org/10.1016/j.ijpara.2024.09.001","url":null,"abstract":"<p><p>Ticks are important medical and veterinary parasites that represent a substantial health threat to humans, companion animals, and livestock. Ixodiphagus wasps (Hymenoptera; Encyrtidae) are known endoparasitoids of ixodid (hard) and argasid (soft) ticks, with potential utility as natural biocontrol agents. Two species, Ixodiphagus brunneus and Ixodiphagus mysorensis, are previously recorded from Australia, however, the genus lacks formal revisionary work in Australia, and the validity and host ranges of these species remain uncertain. This work aimed to investigate the diversity of Ixodiphagus in Australasia and provide a molecular data resource for future work on these understudied endoparasitoids. We extracted DNA from archival Ixodiphagus specimens from Australian and New Zealand insect collections and performed high-throughput sequencing which resulted in complete or mostly complete mitochondrial genome sequences from 11 specimens, including I. brunneus, Ixodiphagus taiaroaensis, and a novel Ixodiphagus sp. reared from Rhipicephalus linnaei from Townsville, Australia. In addition, approximately 70% of the genome of the Wolbachia endosymbiont of I. brunneus was recovered. Finally, we screened 178 recently collected pooled tick samples from southern New South Wales, Australia, for Ixodiphagus spp. using 28S rRNA and cytochrome c oxidase subunit 1(COI) gene PCR, and recovered 14 positive samples. Phylogenetic analysis of Australasian Ixodiphagus spp. based on 28S rRNA and complete mitochondrial genome sequences determined that members of the Australasian fauna are distinct from Ixodiphagus hookeri (the only other Ixodiphagus species for which genetic data exists), and that at least two distinct species are present in Australia; I. brunneus identified from Ixodes holocyclus and Haemaphysalis bancrofti ticks, and an uncharacterised Ixodiphagus sp. found in Rhipicephalus linnaei ticks from northern Queensland. Furthermore, there was substantial genetic diversity at the 28S rRNA loci among I. brunneus samples, which may represent normal genetic variability or a secondary cryptic species. The molecular data generated here represents the first known for the genus Ixodiphagus in Australasia, doubling that of the world fauna, and provides the first known complete mitochondrial genomes for these important tick parasitoids.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142286308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.05.001
Chagas disease affects millions of people in Colombia and worldwide, with its transmission influenced by ecological, environmental, and anthropogenic factors. There is a notable correlation between vector transmission cycles and the habitats of insect vectors of the parasite. However, the scale at which these cycles operate remains uncertain. While individual triatomine ecotopes such as palms provide conditions for isolated transmission cycles, recent studies examining triatomine blood sources in various habitats suggest a more intricate network of transmission cycles, linking wild ecotopes with human dwellings. This study aims to provide further evidence on the complexity of the scale of Trypanosoma cruzi transmission cycles, by exploring the different blood sources among developmental stages of infected triatomines in different habitats. We evaluated infection rates, parasite loads, feeding sources, and the distribution of Rhodnius prolixus insects in Attalea butyracea palms across three distinct habitats in Casanare, Colombia: peridomestics, pastures, and woodlands. Our results show that there is no clear independence in transmission cycles in each environment. Analyses of feeding sources suggest the movement of insects and mammals (primarily bats and didelphids) among habitats. A significant association was found between habitat and instar stages in collected R. prolixus. The N1 stage was correlated with pasture and woodland, while the N4 stage was related to pasture. Additionally, adult insects exhibited higher T. cruzi loads than N1, N2, and N3. We observed higher T. cruzi loads in insects captured in dwelling and pasture habitats, compared with those captured in woodland areas. Effective Chagas disease control strategies must consider the complexity of transmission cycles and the interplay between domestic and sylvatic populations of mammals and vectors.
南美锥虫病影响着哥伦比亚和全世界数百万人,其传播受生态、环境和人为因素的影响。病媒传播周期与寄生虫昆虫病媒的栖息地之间存在明显的相关性。然而,这些周期的运作规模仍不确定。虽然棕榈树等个别三蠹生态群落为孤立的传播周期提供了条件,但最近对不同栖息地的三蠹血源进行的研究表明,传播周期网络更加错综复杂,将野生生态群落与人类居住地联系在一起。本研究旨在通过探究不同栖息地中受感染三蠹发育阶段的不同血液来源,进一步证明克氏锥虫传播周期规模的复杂性。我们评估了哥伦比亚卡萨纳雷三种不同栖息地(围牧场、牧场和林地)的感染率、寄生虫量、食源以及Attalea butyracea棕榈中Rhodnius prolixus昆虫的分布情况。我们的研究结果表明,每种环境中的传播周期都没有明显的独立性。对食物来源的分析表明,昆虫和哺乳动物(主要是蝙蝠和蚜虫)在不同的栖息地之间流动。在采集到的 R. prolixus 中,栖息地与分化阶段之间存在明显的关联。N1 阶段与牧场和林地相关,而 N4 阶段与牧场相关。此外,与 N1、N2 和 N3 相比,成虫表现出更高的 T. cruzi 负荷。我们观察到,与在林地捕获的昆虫相比,在住所和牧场捕获的昆虫体内有更高的南美锥虫病病毒载量。有效的南美锥虫病控制策略必须考虑到传播周期的复杂性,以及哺乳动物和病媒在家养种群和草原种群之间的相互作用。
{"title":"Exploring dietary differences among developmental stages of triatomines infected with Trypanosoma cruzi in different habitats","authors":"","doi":"10.1016/j.ijpara.2024.05.001","DOIUrl":"10.1016/j.ijpara.2024.05.001","url":null,"abstract":"<div><p>Chagas disease affects millions of people in Colombia and worldwide, with its transmission influenced by ecological, environmental, and anthropogenic factors. There is a notable correlation between vector transmission cycles and the habitats of insect vectors of the parasite. However, the scale at which these cycles operate remains uncertain. While individual triatomine ecotopes such as palms provide conditions for isolated transmission cycles, recent studies examining triatomine blood sources in various habitats suggest a more intricate network of transmission cycles, linking wild ecotopes with human dwellings. This study aims to provide further evidence on the complexity of the scale of <em>Trypanosoma cruzi</em> transmission cycles, by exploring the different blood sources among developmental stages of infected triatomines in different habitats. We evaluated infection rates, parasite loads, feeding sources, and the distribution of <em>Rhodnius prolixus</em> insects in <em>Attalea butyracea</em> palms across three distinct habitats in Casanare, Colombia: peridomestics, pastures, and woodlands. Our results show that there is no clear independence in transmission cycles in each environment. Analyses of feeding sources suggest the movement of insects and mammals (primarily bats and didelphids) among habitats. A significant association was found between habitat and instar stages in collected <em>R. prolixus</em>. The N1 stage was correlated with pasture and woodland, while the N4 stage was related to pasture. Additionally, adult insects exhibited higher <em>T. cruzi</em> loads than N1, N2, and N3. We observed higher <em>T. cruzi</em> loads in insects captured in dwelling and pasture habitats, compared with those captured in woodland areas. Effective Chagas disease control strategies must consider the complexity of transmission cycles and the interplay between domestic and sylvatic populations of mammals and vectors.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 11","pages":"Pages 559-568"},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001073/pdfft?md5=96a3bbd4f11f3639150ed3d465355083&pid=1-s2.0-S0020751924001073-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140957274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.05.004
Alveolar echinococcosis (AE) is a rare but severe disease that affects more than 18,000 people worldwide per year. The complete sequencing of the mitochondrial genome of Echinococcus multilocularis has made it possible to study the genetic diversity of the parasite and its spatial and temporal evolution. We amplified the whole mitochondrial genome by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, and then sequenced the amplicons with Illumina technology. In total, 113 samples from Europe, Asia, the Arctic and North America were analyzed. Three major haplogroups were found: HG1, which clustered samples from Alaska (including Saint-Lawrence Island), Yakutia (Russia) and Svalbard; HG2, with samples from Asia, North America and Europe; and HG3, subdivided into three micro-haplogroups. HG3a included samples from North America and Europe, whereas HG3b and HG3c only include samples from Europe. In France, HG3a included samples from patients more recently diagnosed in a region outside the historical endemic area. A fourth putative haplogroup, HG4, was represented by only one isolate from Olkhon Island (Russia). The increased discriminatory power of the complete sequencing of the E. multilocularis mitogenome has made it possible to highlight four distinct geographical clusters, one being divided into three micro-haplogroups in France.
{"title":"Challenging the phylogenetic relationships among Echinococcus multilocularis isolates from main endemic areas","authors":"","doi":"10.1016/j.ijpara.2024.05.004","DOIUrl":"10.1016/j.ijpara.2024.05.004","url":null,"abstract":"<div><p>Alveolar echinococcosis (AE) is a rare but severe disease that affects more than 18,000 people worldwide per year. The complete sequencing of the mitochondrial genome of <em>Echinococcus multilocularis</em> has made it possible to study the genetic diversity of the parasite and its spatial and temporal evolution. We amplified the whole mitochondrial genome by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, and then sequenced the amplicons with Illumina technology. In total, 113 samples from Europe, Asia, the Arctic and North America were analyzed. Three major haplogroups were found: HG1, which clustered samples from Alaska (including Saint-Lawrence Island), Yakutia (Russia) and Svalbard; HG2, with samples from Asia, North America and Europe; and HG3, subdivided into three micro-haplogroups. HG3a included samples from North America and Europe, whereas HG3b and HG3c only include samples from Europe. In France, HG3a included samples from patients more recently diagnosed in a region outside the historical endemic area. A fourth putative haplogroup, HG4, was represented by only one isolate from Olkhon Island (Russia). The increased discriminatory power of the complete sequencing of the <em>E. multilocularis</em> mitogenome has made it possible to highlight four distinct geographical clusters, one being divided into three micro-haplogroups in France.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 11","pages":"Pages 569-582"},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001103/pdfft?md5=c44d4ca1242fced2990e0efdff091bef&pid=1-s2.0-S0020751924001103-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141179468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.04.008
Parasites can indirectly impact hosts through non-consumptive effects (NCEs) via changes in behaviour, morphology, and/or physiology. These responses can be understood in terms of the ecology of fear (ectoparasites) or the ecology of disgust (endoparasites) framework. We tested the hypothesis that NCEs of parasite exposure (e.g., parasite avoidance and defense) trade off with other important behaviours such as feeding and resting. We predicted that when exposed to parasites (without infection), hosts will increase their defensive behaviors at the expense of feeding. We also posited that history of exposure (without infection), or previous infection would impact the expression of these NCEs. The study system involves a cactophilic fruit fly (Drosophila nigrospiracula) and a naturally occurring parasitic mite (Macrocheles subbadius). First, we assessed how prior mite exposure affected fly behaviour in response to current parasite exposure. Mite presence resulted in increased grooming and movement, but exposure history did not affect these behaviours. However, the interaction between previous and current exposure influenced host feeding and resting behaviours. We found that previously exposed flies increased feeding and decreased resting upon a secondary mite exposure. In a second experiment, we tested the role of infection history on current parasite exposure. Compared with naïve flies, previously infected flies were expected to increase defensive behaviours upon secondary exposure. Flies increased defensive and ambulatory behaviour in the presence of mites, and consequently less time was spent resting but feeding was unaffected. None of the behaviours measured were affected by previous infection status. In general, current parasite exposure resulted in NCEs. Moreover, our results showed that previous exposure (without infection) to parasites may have an even stronger effect upon secondary exposure than infection history. Our study highlights the importance of the ecology of fear and the role that exposure and infection history plays in generating NCEs of parasitism.
{"title":"Ghosts of parasites past influence current non-consumptive effects in Drosophila nigrospiracula","authors":"","doi":"10.1016/j.ijpara.2024.04.008","DOIUrl":"10.1016/j.ijpara.2024.04.008","url":null,"abstract":"<div><p>Parasites can indirectly impact hosts through non-consumptive effects (NCEs) via changes in behaviour, morphology, and/or physiology. These responses can be understood in terms of the ecology of fear (ectoparasites) or the ecology of disgust (endoparasites) framework. We tested the hypothesis that NCEs of parasite exposure (e.g., parasite avoidance and defense) trade off with other important behaviours such as feeding and resting. We predicted that when exposed to parasites (without infection), hosts will increase their defensive behaviors at the expense of feeding. We also posited that history of exposure (without infection), or previous infection would impact the expression of these NCEs. The study system involves a cactophilic fruit fly (<em>Drosophila nigrospiracula</em>) and a naturally occurring parasitic mite (<em>Macrocheles subbadius</em>). First, we assessed how prior mite exposure affected fly behaviour in response to current parasite exposure. Mite presence resulted in increased grooming and movement, but exposure history did not affect these behaviours. However, the interaction between previous and current exposure influenced host feeding and resting behaviours. We found that previously exposed flies increased feeding and decreased resting upon a secondary mite exposure. In a second experiment, we tested the role of infection history on current parasite exposure. Compared with naïve flies, previously infected flies were expected to increase defensive behaviours upon secondary exposure. Flies increased defensive and ambulatory behaviour in the presence of mites, and consequently less time was spent resting but feeding was unaffected. None of the behaviours measured were affected by previous infection status. In general, current parasite exposure resulted in NCEs. Moreover, our results showed that previous exposure (without infection) to parasites may have an even stronger effect upon secondary exposure than infection history. Our study highlights the importance of the ecology of fear and the role that exposure and infection history plays in generating NCEs of parasitism.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 11","pages":"Pages 551-558"},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S002075192400078X/pdfft?md5=071607e5ac2bf5976c8f7eeb0ce9c541&pid=1-s2.0-S002075192400078X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140793131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.05.003
Xenobiotic biotransformation is an important modulator of anthelmintic drug potency and a potential mechanism of anthelmintic resistance. Both the free-living nematode Caenorhabditis elegans and the ruminant parasite Haemonchus contortus biotransform benzimidazole drugs by glucose conjugation, likely catalysed by UDP-glycosyltransferase (UGT) enzymes. To identify C. elegans genes involved in benzimidazole drug detoxification, we first used a comparative phylogenetic analysis of UGTs from humans, C. elegans and H. contortus, combined with available RNAseq datasets to identify which of the 63 C. elegans ugt genes are most likely to be involved in benzimidazole drug biotransformation. RNA interference knockdown of 15 prioritized C. elegans genes identified those that sensitized animals to the benzimidazole derivative albendazole (ABZ). Genetic mutations subsequently revealed that loss of ugt-9 and ugt-11 had the strongest effects. The “ugt-9 cluster” includes these genes, together with six other closely related ugts. A CRISPR-Cas-9 deletion that removed seven of the eight ugt-9 cluster genes had greater ABZ sensitivity than the single largest-effect mutation. Furthermore, a double mutant of ugt-22 (which is not a member of the ugt-9 cluster) with the ugt-9 cluster deletion further increased ABZ sensitivity. This additivity of mutant phenotypes suggest that ugt genes act in parallel, which could have several, not mutually exclusive, explanations. ugt mutations have different effects with different benzimidazole derivatives, suggesting that enzymes with different specificities could together more efficiently detoxify drugs. Expression patterns of ugt-9, ugt-11 and ugt-22 gfp reporters differ and so likely act in different tissues which may, at least in part, explain their additive effects on drug potency. Overexpression of ugt-9 alone was sufficient to confer partial ABZ resistance, indicating increasing total UGT activity protects animals. In summary, our results suggest that the multiple UGT enzymes have overlapping but not completely redundant functions in benzimidazole drug detoxification and may represent “druggable” targets to improve benzimidazole drug potency.
{"title":"Multiple UDP glycosyltransferases modulate benzimidazole drug sensitivity in the nematode Caenorhabditis elegans in an additive manner","authors":"","doi":"10.1016/j.ijpara.2024.05.003","DOIUrl":"10.1016/j.ijpara.2024.05.003","url":null,"abstract":"<div><p>Xenobiotic biotransformation is an important modulator of anthelmintic drug potency and a potential mechanism of anthelmintic resistance. Both the free-living nematode <em>Caenorhabditis elegans</em> and the ruminant parasite <em>Haemonchus contortus</em> biotransform benzimidazole drugs by glucose conjugation, likely catalysed by UDP-glycosyltransferase (UGT) enzymes. To identify <em>C. elegans</em> genes involved in benzimidazole drug detoxification, we first used a comparative phylogenetic analysis of UGTs from humans<em>, C. elegans</em> and <em>H. contortus,</em> combined with available RNAseq datasets to identify which of the 63 <em>C. elegans ugt</em> genes are most likely to be involved in benzimidazole drug biotransformation<em>.</em> RNA interference knockdown of 15 prioritized <em>C. elegans</em> genes identified those that sensitized animals to the benzimidazole derivative albendazole (ABZ). Genetic mutations subsequently revealed that loss of <em>ugt-9</em> and <em>ugt-11</em> had the strongest effects. The “<em>ugt-9 cluster</em>” includes these genes, together with six other closely related <em>ugt</em>s. A CRISPR-Cas-9 deletion that removed seven of the eight <em>ugt-9 cluster</em> genes had greater ABZ sensitivity than the single largest-effect mutation. Furthermore, a double mutant of <em>ugt-22</em> (which is not a member of the <em>ugt-9 cluster)</em> with the <em>ugt-9 cluster</em> deletion further increased ABZ sensitivity. This additivity of mutant phenotypes suggest that <em>ugt</em> genes act in parallel, which could have several, not mutually exclusive, explanations. <em>ugt</em> mutations have different effects with different benzimidazole derivatives, suggesting that enzymes with different specificities could together more efficiently detoxify drugs. Expression patterns of <em>ugt-9, ugt-11</em> and <em>ugt-22 gfp</em> reporters differ and so likely act in different tissues which may, at least in part, explain their additive effects on drug potency. Overexpression of <em>ugt-9</em> alone was sufficient to confer partial ABZ resistance, indicating increasing total UGT activity protects animals. In summary, our results suggest that the multiple UGT enzymes have overlapping but not completely redundant functions in benzimidazole drug detoxification and may represent “druggable” targets to improve benzimidazole drug potency.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 11","pages":"Pages 535-549"},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001097/pdfft?md5=1b485fbd725694b19b4f5bc56ae0cd6f&pid=1-s2.0-S0020751924001097-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141161331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.06.003
Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of Toxoplasma gondii. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which T. gondii acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in T. gondii. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δgra23Δgra72 was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δgra23 strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δgra47, Δgra72 and Δgra17, while the expression of the Plasmodium falciparum PVM protein PfExp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δgra strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in T. gondii, which may contribute to the parasite’s remarkable ability to grow in different cellular niches in a very broad range of hosts.
{"title":"GRA47 is important for the morphology and permeability of the parasitophorous vacuole in Toxoplasma gondii","authors":"","doi":"10.1016/j.ijpara.2024.06.003","DOIUrl":"10.1016/j.ijpara.2024.06.003","url":null,"abstract":"<div><p>Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of <span><em>Toxoplasma gondii</em></span><span>. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which </span><em>T. gondii</em> acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in <em>T. gondii</em>. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δ<em>gra</em>23Δ<em>gra72</em> was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δ<em>gra23</em> strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δ<em>gra47</em>, Δ<em>gra72</em> and Δ<em>gra17</em>, while the expression of the <em>Plasmodium falciparum</em> PVM protein <em>Pf</em>Exp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δ<em>gra</em> strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in <em>T. gondii</em>, which may contribute to the parasite’s remarkable ability to grow in different cellular niches in a very broad range of hosts.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 11","pages":"Pages 583-596"},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141467798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-30DOI: 10.1016/j.ijpara.2024.08.005
Célia Koellsch, Robert Poulin, Priscila M Salloum
The fast technological advances of molecular tools have enabled us to uncover a new dimension hidden within parasites and their hosts: their microbiomes. Increasingly, parasitologists characterise host microbiome changes in the face of parasitic infections, revealing the potential of these microscopic fast-evolving entities to influence host-parasite interactions. However, most of the changes in host microbiomes seem to depend on the host and parasite species in question. Furthermore, we should understand the relative role of parasitic infections as microbiome modulators when compared with other microbiome-impacting factors (e.g., host size, age, sex). Here, we characterised the microbiome of a single intermediate host species infected by two parasites belonging to different phyla: the acanthocephalan Plagiorhynchus allisonae and a dilepidid cestode, both infecting Transorchestia serrulata amphipods collected simultaneously from the same locality. We used the v4 hypervariable region of the 16S rRNA prokaryotic gene to identify the hemolymph bacterial community of uninfected, acanthocephalan-infected, and cestode-infected amphipods, as well as the bacteria in the amphipods' immediate environment and in the parasites infecting them. Our results show that parasitic infections were more strongly associated with differences in host bacterial community richness than amphipod size, presence of amphipod eggs in female amphipods, and even parasite load. Amphipods infected by acanthocephalans had the most divergent bacterial community, with a marked decrease in alpha diversity compared with cestode-infected and uninfected hosts. In accordance with the species-specific nature of microbiome changes in parasitic infections, we found unique microbial taxa associating with hosts infected by each parasite species, as well as taxa only shared between a parasite species and their infected hosts. However, there were some bacterial taxa detected in all parasitised amphipods (regardless of the parasite species), but not in uninfected amphipods or the environment. We propose that shared bacteria associated with all hosts parasitised by distantly related helminths may be important either in helping host defences or parasites' success, and could thus interact with host-parasite evolution.
{"title":"What shapes a microbiome? Differences in bacterial communities associated with helminth-amphipod interactions.","authors":"Célia Koellsch, Robert Poulin, Priscila M Salloum","doi":"10.1016/j.ijpara.2024.08.005","DOIUrl":"10.1016/j.ijpara.2024.08.005","url":null,"abstract":"<p><p>The fast technological advances of molecular tools have enabled us to uncover a new dimension hidden within parasites and their hosts: their microbiomes. Increasingly, parasitologists characterise host microbiome changes in the face of parasitic infections, revealing the potential of these microscopic fast-evolving entities to influence host-parasite interactions. However, most of the changes in host microbiomes seem to depend on the host and parasite species in question. Furthermore, we should understand the relative role of parasitic infections as microbiome modulators when compared with other microbiome-impacting factors (e.g., host size, age, sex). Here, we characterised the microbiome of a single intermediate host species infected by two parasites belonging to different phyla: the acanthocephalan Plagiorhynchus allisonae and a dilepidid cestode, both infecting Transorchestia serrulata amphipods collected simultaneously from the same locality. We used the v4 hypervariable region of the 16S rRNA prokaryotic gene to identify the hemolymph bacterial community of uninfected, acanthocephalan-infected, and cestode-infected amphipods, as well as the bacteria in the amphipods' immediate environment and in the parasites infecting them. Our results show that parasitic infections were more strongly associated with differences in host bacterial community richness than amphipod size, presence of amphipod eggs in female amphipods, and even parasite load. Amphipods infected by acanthocephalans had the most divergent bacterial community, with a marked decrease in alpha diversity compared with cestode-infected and uninfected hosts. In accordance with the species-specific nature of microbiome changes in parasitic infections, we found unique microbial taxa associating with hosts infected by each parasite species, as well as taxa only shared between a parasite species and their infected hosts. However, there were some bacterial taxa detected in all parasitised amphipods (regardless of the parasite species), but not in uninfected amphipods or the environment. We propose that shared bacteria associated with all hosts parasitised by distantly related helminths may be important either in helping host defences or parasites' success, and could thus interact with host-parasite evolution.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142107086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}