International journal for parasitology最新文献

{"title":"What shapes a microbiome? Differences in bacterial communities associated with helminth-amphipod interactions","authors":"Célia Koellsch,&nbsp;Robert Poulin,&nbsp;Priscila M. Salloum","doi":"10.1016/j.ijpara.2024.08.005","DOIUrl":"10.1016/j.ijpara.2024.08.005","url":null,"abstract":"<div><div>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 <em>Plagiorhynchus allisonae</em> and a dilepidid cestode, both infecting <em>Transorchestia serrulata</em> 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.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 14","pages":"Pages 733-742"},"PeriodicalIF":3.7,"publicationDate":"2024-12-01","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterisation of Australasian Ixodiphagus (Hymenoptera; Encyrtidae; Encyrtinae) reveals unexpected diversity and a potential novel host switch","authors":"Madalene M. Giannotta ,&nbsp;Ina Smith ,&nbsp;Michelle Michie ,&nbsp;Kim Blasdell ,&nbsp;Mike Dunn ,&nbsp;James Nicholls ,&nbsp;Allen C.G. Heath ,&nbsp;Juanita Rodriguez ,&nbsp;Alexander W. Gofton","doi":"10.1016/j.ijpara.2024.09.001","DOIUrl":"10.1016/j.ijpara.2024.09.001","url":null,"abstract":"<div><div>Ticks are important medical and veterinary parasites that represent a substantial health threat to humans, companion animals, and livestock. <em>Ixodiphagus</em> wasps (Hymenoptera; Encyrtidae) are known endoparasitoids of ixodid (hard) and argasid (soft) ticks, with potential utility as natural biocontrol agents. Two species, <em>Ixodiphagus brunneus</em> and <em>Ixodiphagus mysorensis,</em> 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 <em>Ixodiphagus</em> in Australasia and provide a molecular data resource for future work on these understudied endoparasitoids. We extracted DNA from archival <em>Ixodiphagus</em> 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 <em>I. brunneus, Ixodiphagus taiaroaensis</em>, and a novel <em>Ixodiphagus</em> sp. reared from <em>Rhipicephalus linnaei</em> from Townsville, Australia. In addition, approximately 70% of the genome of the <em>Wolbachia</em> endosymbiont of <em>I. brunneus</em> was recovered<em>.</em> Finally, we screened 178 recently collected pooled tick samples from southern New South Wales, Australia, for <em>Ixodiphagus</em> spp. using 28S rRNA and cytochrome <em>c</em> oxidase subunit 1(<em>COI</em>) gene PCR, and recovered 14 positive samples. Phylogenetic analysis of Australasian <em>Ixodiphagus</em> spp. based on 28S rRNA and complete mitochondrial genome sequences determined that members of the Australasian fauna are distinct from <em>Ixodiphagus hookeri</em> (the only other <em>Ixodiphagus</em> species for which genetic data exists), and that at least two distinct species are present in Australia; <em>I. brunneus</em> identified from <em>Ixodes holocyclus</em> and <em>Haemaphysalis bancrofti</em> ticks, and an uncharacterised <em>Ixodiphagus</em> sp. found in <em>Rhipicephalus linnaei</em> ticks from northern Queensland. Furthermore, there was substantial genetic diversity at the 28S rRNA loci among <em>I. brunneus</em> samples, which may represent normal genetic variability or a secondary cryptic species. The molecular data generated here represents the first known for the genus <em>Ixodiphagus</em> in Australasia, doubling that of the world fauna, and provides the first known complete mitochondrial genomes for these important tick parasitoids.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 14","pages":"Pages 743-753"},"PeriodicalIF":3.7,"publicationDate":"2024-12-01","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"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 ,&nbsp;Xavier Matthey ,&nbsp;Didier Marcon ,&nbsp;Camille Coffre-Thomain ,&nbsp;Lucie Estivalet ,&nbsp;Delphine Serreau ,&nbsp;Fabrice Guégnard ,&nbsp;Guillaume Sallé ,&nbsp;Papa Moussa Drame ,&nbsp;Frédéric Elleboudt ,&nbsp;François Lecompte ,&nbsp;Hans Adriaensen","doi":"10.1016/j.ijpara.2024.09.004","DOIUrl":"10.1016/j.ijpara.2024.09.004","url":null,"abstract":"<div><div>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 <em>Haemonchus contortus</em> that we experimentally infected (<em>n</em> = 60) or not (<em>n</em> = 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.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 14","pages":"Pages 767-777"},"PeriodicalIF":3.7,"publicationDate":"2024-12-01","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":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The invasive acanthocephalan parasite Pachysentis canicola is associated with a declining endemic island fox population on San Miguel Island","authors":"O. Alejandro Aleuy ,&nbsp;Leslie W. Woods ,&nbsp;Benjamin J. Padilla ,&nbsp;Dennis Richardson ,&nbsp;Juliann T. Schamel ,&nbsp;Stacy Baker ,&nbsp;Martín García-Varela ,&nbsp;Charlotte Hammond ,&nbsp;Sarah P. Lawson ,&nbsp;Jasmine N. Childress ,&nbsp;Jason Rohr ,&nbsp;Kevin D. Lafferty","doi":"10.1016/j.ijpara.2024.09.003","DOIUrl":"10.1016/j.ijpara.2024.09.003","url":null,"abstract":"<div><div>In the late 1990s, the San Miguel Island fox (<em>Urocyon littoralis littoralis</em>) 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 <em>Pachysentis canicola,</em> 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.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 14","pages":"Pages 723-732"},"PeriodicalIF":3.7,"publicationDate":"2024-12-01","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}

{"title":"Genomic and metagenomic analyses of the domestic mite Tyrophagus putrescentiae identify it as a widespread environmental contaminant and a host of a basal, mite-specific Wolbachia lineage (supergroup Q)","authors":"Pavel B. Klimov ,&nbsp;Jan Hubert ,&nbsp;Tomas Erban ,&nbsp;M. Alejandra Perotti ,&nbsp;Henk R. Braig ,&nbsp;Alex Flynt ,&nbsp;Qixin He ,&nbsp;Yubao Cui","doi":"10.1016/j.ijpara.2024.07.001","DOIUrl":"10.1016/j.ijpara.2024.07.001","url":null,"abstract":"<div><div><em>Tyrophagus putrescentiae</em> (mould mite) is a global, microscopic trophic generalist that commonly occurs in various human-created habitats, causing allergies and damaging stored food. Its ubiquity and extraordinary ability to penetrate research samples or cultures through air currents or by active walking through tights spaces (such as treads of screw caps) may lead to sample contamination and introduction of its DNA to research materials in the laboratory. This prompts a thorough investigation into potential sequence contamination in public genomic databases. The trophic success of <em>T. putrescentiae</em> is primarily attributed to the symbiotic bacteria housed in specialized internal mite structures, facilitating adaptation to varied nutritional niches. However, recent work suggests that horizontal transfer of bacterial/fungal genes related to nutritional functionality may also contribute to the mite’s trophic versatility. This aspect requires independent confirmation. Additionally, <em>T. putrescentiae</em> harbors an uncharacterized and genetically divergent bacterium, <em>Wolbachia</em>, displaying blocking and microbiome-modifying effects. The phylogenomic position and supergroup assignment of this bacterium are unknown. Here, we sequenced and assembled the <em>T. putrescentiae</em> genome, analyzed its microbiome, and performed detailed phylogenomic analyses of the mite-specific <em>Wolbachia</em>. We show that <em>T. putrescentiae</em> DNA is a substantial source of contamination of research samples. Its DNA may inadvertently be co-extracted with the DNA of the target organism, eventually leading to sequence contamination in public databases. We identified a diversity of bacterial species associated with <em>T. putrescentiae</em>, including those capable of rapidly developing antibiotic resistance, such as <em>Escherichia coli</em>. Despite the presence of diverse bacterial communities in <em>T. putrescentiae</em>, we did not detect any recent horizontal gene transfers in this mite species and/or in astigmatid (domestic) mites in general. Our phylogenomic analysis of <em>Wolbachia</em> recovered a basal, mite-specific lineage (supergroup Q) represented by two <em>Wolbachia</em> spp. from the mould mite and a gall-inducing plant mite. Fluorescence in situ hybridization confirmed the presence of <em>Wolbachia</em> inside the mould mite<em>.</em> The discovery of an early derivative <em>Wolbachia</em> lineage (supergroup Q) in two phylogenetically unrelated and ecologically dissimilar mites suggests that this endosymbiotic bacterial lineage formed a long-term association with mites. This finding provides a unique insight into the early evolution and host associations of <em>Wolbachia</em>. Further discoveries of <em>Wolbachia</em> diversity in acariform mites are anticipated.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 661-674"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141590232","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}

{"title":"Chromosome-contiguous genome for the Haecon-5 strain of Haemonchus contortus reveals marked genetic variability and enables the discovery of essential gene candidates","authors":"Yuanting Zheng ,&nbsp;Neil D. Young ,&nbsp;Tulio L. Campos ,&nbsp;Pasi K. Korhonen ,&nbsp;Tao Wang ,&nbsp;Sunita B. Sumanam ,&nbsp;Aya C. Taki ,&nbsp;Joseph J. Byrne ,&nbsp;Bill C.H. Chang ,&nbsp;Jiangning Song ,&nbsp;Robin B. Gasser","doi":"10.1016/j.ijpara.2024.08.003","DOIUrl":"10.1016/j.ijpara.2024.08.003","url":null,"abstract":"<div><div>Millions of livestock animals worldwide are infected with the haematophagous barber’s pole worm, <em>Haemonchus contortus</em>, the aetiological agent of haemonchosis. Despite the major significance of this parasite worldwide and its widespread resistance to current treatments, the lack of a high-quality genome for the well-defined strain of this parasite from Australia, called Haecon-5, has constrained research in a number of areas including host-parasite interactions, drug discovery and population genetics. To enable research in these areas, we report here a chromosome-contiguous genome (∼280 Mb) for Haecon-5 with high-quality models for 19,234 protein-coding genes. Comparative genomic analyses show significant genomic similarity (synteny) with a UK strain of <em>H. contortus</em>, called MHco3(ISE).N1 (abbreviated as “ISE”), but we also discover marked differences in genomic structure/gene arrangements, distribution of nucleotide variability (single nucleotide polymorphisms (SNPs) and indels) and orthology between Haecon-5 and ISE. We used the genome and extensive transcriptomic resources for Haecon-5 to predict a subset of essential single-copy genes employing a “cross-species” machine learning (ML) approach using a range of features from nucleotide/protein sequences, protein orthology, subcellular localisation, single-cell RNA-seq and/or histone methylation data available for the model organisms <em>Caenorhabditis elegans</em> and <em>Drosophila melanogaster</em>. From a set of 1,464 conserved single copy genes, transcribed in key life-cycle stages of <em>H. contortus</em>, we identified 232 genes whose homologs have critical functions in <em>C. elegans</em> and/or <em>D. melanogaster</em>, and prioritised 10 of them for further characterisation; nine of the 10 genes likely play roles in neurophysiological processes, germline, hypodermis and/or respiration, and one is an unknown (orphan) gene for which no detailed functional information exists. Future studies of these genes/gene products are warranted to elucidate their roles in parasite biology, host-parasite interplay and/or disease. Clearly, the present Haecon-5 reference genome and associated resources now underpin a broad range of fundamental investigations of <em>H. contortus</em> and could assist in accelerating the discovery of novel intervention targets and drug candidates to combat haemonchosis.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 705-715"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017329","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}

{"title":"Micro RNA profiles of host extracellular vesicles are modulated by Ascaris suum infection but parasite extracellular vesicle miRNAs are systemically undetectable using in-depth miRNA sequencing","authors":"Bradley Whitehead ,&nbsp;Litten Sørensen Rossen ,&nbsp;Mads Zippor ,&nbsp;Anders T. Boysen ,&nbsp;Vineesh Indira Chandran ,&nbsp;Per Skallerup ,&nbsp;Stig M. Thamsborg ,&nbsp;Peter Nejsum","doi":"10.1016/j.ijpara.2024.08.001","DOIUrl":"10.1016/j.ijpara.2024.08.001","url":null,"abstract":"<div><div>The intestinal helminth <em>Ascaris lumbricoides</em> infects over 800 million people. Infections are often chronic and immunity is not sterilizing due to host-immune modulation, therefore reinfection is common after antihelmintic treatment. We have previously demonstrated a role for <em>Ascaris</em> spp. extracellular vesicles (EVs) in host immune modulation but whether EVs are recognized by the adaptive immune system and are present systemically in the host remains unknown. Therefore, we employed a well-established trickle infection model in pigs to mimic natural <em>Ascaris</em> infection in humans. EVs were isolated from adult <em>Ascaris suum</em> followed by immunoblotting of EV and EV-depleted secretory fractions using plasma from infected and uninfected pigs. Next, EVs were isolated from pig plasma at day 56 post first infection and subjected to deep small RNAseq analysis. RNAs were aligned to <em>A. suum</em> and <em>Sus scrofa</em> miRNA complements to detect <em>A. suum</em> EVs and elucidate the host EV micro RNA (miRNA) response to infection, respectively. Infection generates robust antibody responses against <em>A. suum</em> EVs that is distinct from EV-depleted fractions. However, <em>A. suum</em> miRNAs were not detectable in EVs from the peripheral blood. Notably, host plasma-derived EV miRNA profiles showed significant changes between infected and uninfected pigs, indicating that <em>Ascaris</em> infection drives systemic changes in host EV composition.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 691-696"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141906580","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}

{"title":"DNA N-glycosylases Ogg1 and EndoIII as components of base excision repair in Plasmodium falciparum organelles","authors":"Anupama Tiwari ,&nbsp;Neetu Verma ,&nbsp;Himadri Shukla ,&nbsp;Shivani Mishra ,&nbsp;Kit Kennedy ,&nbsp;Tribeni Chatterjee ,&nbsp;Jitendra Kuldeep ,&nbsp;Shahid Parwez ,&nbsp;MI Siddiqi ,&nbsp;Stuart A. Ralph ,&nbsp;Satish Mishra ,&nbsp;Saman Habib","doi":"10.1016/j.ijpara.2024.06.005","DOIUrl":"10.1016/j.ijpara.2024.06.005","url":null,"abstract":"<div><div>The integrity of genomes of the two crucial organelles of the malaria parasite — an apicoplast and mitochondrion in each cell − must be maintained by DNA repair mediated by proteins targeted to these compartments. We explored the localisation and function of <em>Plasmodium falciparum</em><span> base excision repair (BER) DNA N-glycosylase homologs </span><em>Pf</em>EndoIII and <em>Pf</em>Ogg1. These N-glycosylases would putatively recognise DNA lesions prior to the action of apurinic/apyrimidinic (AP)-endonucleases. Both Ape1 and Apn1 endonucleases have earlier been shown to function solely in the parasite mitochondrion. Immunofluorescence localisation showed that <em>Pf</em>EndoIII was exclusively mitochondrial. <em>Pf</em>Ogg1 was not seen clearly in mitochondria when expressed as a <em>Pf</em>Ogg1_leader-GFP fusion, although chromatin immunoprecipitation assays showed that it could interact with both mitochondrial and apicoplast DNA. Recombinant <em>Pf</em>EndoIII functioned as a DNA N-glycosylase as well as an AP-lyase on thymine glycol (Tg) lesions. We further studied the importance of Ogg1 in the malaria life cycle using reverse genetic approaches in <em>Plasmodium berghei</em>. Targeted disruption of <em>Pb</em>Ogg1 resulted in loss of 8-oxo-G specific DNA glycosylase/lyase activity. <em>Pb</em>Ogg1 knockout did not affect blood, mosquito or liver stage development but caused reduced blood stage infection after inoculation of sporozoites in mice. A significant reduction in erythrocyte infectivity by <em>Pb</em>Ogg1 knockout hepatic merozoites was also observed, thus showing that <em>Pb</em>Ogg1 ensures smooth transition from liver to blood stage infection. Our results strengthen the view that the <em>Plasmodium</em><span> mitochondrial genome is an important site for DNA repair by the BER pathway.</span></div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 675-689"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141534413","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}

{"title":"The concentration McMaster method for diagnosis of patent Ascaris and Trichuris infections in humans","authors":"Sozan Kader ,&nbsp;Christine E. Helmersen ,&nbsp;Stig M. Thamsborg ,&nbsp;Lise T. Erikstrup ,&nbsp;Peter Nejsum","doi":"10.1016/j.ijpara.2024.08.004","DOIUrl":"10.1016/j.ijpara.2024.08.004","url":null,"abstract":"<div><div>In tropical and subtropical regions, soil-transmitted helminth (STH) infections such as <em>Ascaris lumbricoides</em>, <em>Trichuris trichiura</em>, and hookworms have a significant impact on public health. Globally, <em>A. lumbricoides</em> infects approximately 0.8 billion people, while <em>T. trichiura</em> infects around 500 million. This study involved a comparison of three diagnostic methods, Kato-Katz and two flotation methods (concentration McMaster, and simple McMaster), for the detection of <em>Ascaris</em> and <em>Trichuris</em> in human faeces. We conducted a comparison of the number of eggs in faeces (or faecal egg counts (FECs)) obtained with these methods using freshly collected samples that were positive for <em>T. trichiura</em> and spiked with a known quantity of <em>Ascaris</em> sp. eggs. Additionally, for the concentration McMaster method we assessed FECs after storing the samples at 5 °C for up to 21 days. The concentration McMaster method demonstrated superiority over the simple McMaster method in terms of higher detection levels for both helminths, while the Kato-Katz method yielded FEC values very close to the ’true’ spiking values. Importantly, the concentration McMaster method was considerably easier to read compared with the Kato-Katz method, and it allowed for sample storage at 5 °C for up to 14 days without affecting FEC results. Consequently, we conclude that the concentration McMaster method is an effective and user-friendly alternative for diagnosis of <em>Ascaris</em> and <em>Trichuris</em> infections in humans. Furthermore, it offers the advantage of sample storage before analysis, enhancing flexibility in the workflow.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 717-722"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142107085","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}

{"title":"Potential effects of host competence and schooling behavior on parasite transmission in a host-pathogen system: a test of the dilution effect","authors":"Shun Zhou ,&nbsp;Xiao Jin ,&nbsp;Ming Duan ,&nbsp;Hong Zou ,&nbsp;Ming Li ,&nbsp;David J. Marcogliese ,&nbsp;Guitang Wang ,&nbsp;Wenxiang Li","doi":"10.1016/j.ijpara.2024.08.002","DOIUrl":"10.1016/j.ijpara.2024.08.002","url":null,"abstract":"<div><div>High species diversity in a community may reduce the risk of infectious disease, termed the dilution effect. However, the generality of the dilution effect in different disease systems remains controversial as both host competence and behaviors of hosts may play roles in dilution or amplification of disease. Using the goldfish (<em>Carassius auratus</em>)-monogenean ectoparasite (<em>Gyrodactylus kobayashii</em>) system, effects of host competence and schooling behavior on parasite transmission were investigated while holding focal host density constant. Following competency tests of 12 fish species as potential hosts for the parasite, infection by <em>G. kobayashii</em> was determined on fins of goldfish mixed with each of three different species based on their level of host competence, including Prussian carp, <em>Carassius gibelio</em> (low competence), grass carp, <em>Ctenopharyngodon idellus</em> (non-competent), swordtail, <em>Xiphophorus helleri</em> (non-competent), and the four species combined. Compared with mean abundance (85.8 ± 25.1) on goldfish in the control group, the mean abundance on goldfish decreased significantly when paired with 10 Prussian carp (30.0 ± 16.5), but did not differ significantly when paired with 10 swordtail (70.0 ± 22.2), 10 grass carp (116.1 ± 33.2), or the multi-species of three Prussian carp, four grass carp and three swordtail (75.9 ± 30.8) during the 11-day experiment. The parasite was also found on the Prussian carp in the Prussian carp group and the multi-species group at a mean abundance of 7.1 and 10.9, respectively. Video recording showed that the school of goldfish mixed well with the Prussian carp, while they maintained separation from the grass carp and swordtail when mixed together. The distance between goldfish increased, and swimming speed and contact time decreased with the additional of other fish species for all groups. The results suggested that the presence of a low-competence host in sufficient numbers was a necessary condition for a dilution effect due to encounter reduction, and the dilution effect may also be enhanced by changes in schooling behavior of goldfish in the presence of low competence hosts. However, the presence of non-competent hosts did not result in any dilution effect owing to the specialist nature of the parasites and the lack of mixing with schools of goldfish.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 697-703"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141987900","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}