International journal for parasitology最新文献

{"title":"HpBoRB, a helminth-derived CCP domain protein which binds RELMβ.","authors":"Vivien Shek, Abhishek Jamwal, Danielle J Smyth, Tania Frangova, Alice R Savage, Sarah Kelly, Gavin J Wright, Rachel Toth, Erich M Schwarz, Rick M Maizels, Matthew K Higgins, Alasdair C Ivens, Hermelijn H Smits, Henry J McSorley","doi":"10.1016/j.ijpara.2025.09.006","DOIUrl":"10.1016/j.ijpara.2025.09.006","url":null,"abstract":"<p><p>Helminth infections persist by influencing host immunity through the release of immunomodulatory proteins which prevent immune ejection. The intestinal nematode Heligmosomoides polygyrus bakeri (Hpb) secretes multiple families of immunomodulatory proteins, many of which are composed of consecutive Complement Control Protein (CCP) domains. We hypothesised that further CCP domain proteins are secreted by the parasite to interact with the host. We identified an unusually large number of CCP domain-containing proteins in the genome of Hpb, and cloned a range of these for screening in an Avidity-based Extracellular Interaction Screening (AVEXIS) assay, focussing on interactions with host immune proteins. This screen confirmed the binding of known immunomodulators (HpBARI, TGM1) for their targets (ST2, TGFBR2) and identified a new interaction between a 2 CCP domain Hpb protein and mouse resistin-like molecule beta (RELMβ), a host protein demonstrated to have anti-helminth properties. This protein was named Binder of RELMβ (HpBoRB). This interaction was specific and heat-labile, and was confirmed in ELISA, competition assays, size exclusion chromatography and surface plasmon resonance experiments, identifying a subnanomolar affinity interaction between HpBoRB and RELMβ. These data may indicate that Hpb interferes with the potent anti-helminth host protein RELMβ and adds to our knowledge of the host-parasite interactions mediated by Hpb secreted proteins.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145174182","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":"Climate driven patterns shape clusters of co-occurring ticks and vertebrates in the Western Palearctic-Tropics.","authors":"Agustín Estrada-Peña, Sara R Wijburg, Hein Sprong","doi":"10.1016/j.ijpara.2025.09.005","DOIUrl":"10.1016/j.ijpara.2025.09.005","url":null,"abstract":"<p><p>The assembly of parasite communities is driven by the intricate interplay between geography, climate and host communities, all of which define the range of tick species. Understanding these processes is necessary for uncovering the dynamics behind the circulation of tick-borne pathogens. In this study, we identify traits that define endemicity and ß-diversity patterns in interacting vertebrate and tick communities, based on the distributions of 82 species of ticks and 121 genera of vertebrates across a region that spans the Western Palearctic and the Tropics. Both ß-diversity and endemism exhibit considerable variation between climate regions, with maxima in the Rift Valley, South Africa, and a narrow oceanic band in Namibia. ß-diversity is high in sub-Saharan Africa, and lower in the Western Palearctic. Four chorotypes of co-occurring ticks were identified. Environmental and spatial niche sharing among chorotypes is high, except for certain tick species distributed over the Western Palearctic. Chorotypes display low values of hosts phylogenetic diversity, denoting a low impact of the occurrence of vertebrates on the delineation of chorotypes. Of importance, some ticks that overlap their environmental niche use phylogenetically distant hosts. Chorotypes aid in understanding biodiversity patterns and interactions among hosts and ticks. They are proposed as a framework for investigating the occurrence and spread of tick-borne pathogens. This framework allows a consistent structure for mapping and exploring critical vector-hosts associations in large areas, that could drive key epidemiological patterns of tick-borne diseases.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145124689","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":"A study of the epidemiology of Anoplocephala perfoliata infection in horses and the oribatid mite vector in southern England.","authors":"Hannah Wickenden, Kirsty L Lightbody, Natalia Peczak, Kim B Stevens, Danica Pollard, Damer P Blake, Corrine J Austin, Jacqueline B Matthews, Mark T Fox","doi":"10.1016/j.ijpara.2025.09.003","DOIUrl":"10.1016/j.ijpara.2025.09.003","url":null,"abstract":"<p><p>Anoplocephala perfoliata is the most common equine tapeworm infection. This parasite is found at the small/large intestinal junction and has been associated with colic. The cestode has an indirect lifecycle involving oribatid mite intermediate hosts, though little is known of its epidemiology. This study aimed to monitor seasonal fluctuations in pasture oribatid mite numbers and the presence of Anoplocephala spp. DNA in mite samples collected from three equine premises in the UK. Exposure to infection in resident horses was assessed by measuring tapeworm-specific salivary antibodies. The data were analysed with management information to identify factors associated with the occurrence of (i) pasture samples containing different oribatid families, (ii) mite samples containing Anoplocephala spp. DNA, and (iii) a borderline or moderate high saliva score in the ELISA. Each yard was visited every four weeks (June 2016-August 2017) when three pastures were vacuum-sampled for mites. Three, one metre-square tetrads and grass surrounding 10 faecal pats were sampled per pasture. Mites collected were counted, identified to family level and pooled by family for Anoplocephala spp. DNA screening by polymerase chain reaction (PCR). Saliva samples were screened for A. perfoliata antibodies using the EquiSal® Tapeworm test in 10-23 horses at each yard every 2-3 weeks. Mixed-effects regression models were used to identify risk factors for each of the three outcomes. The results indicated that oribatid mite families not identified previously could act as intermediate hosts for Anoplocephala spp., and established that whilst oribatid mites might be found on pasture year-round, Damaeolidae and Oribatidae were 81 % (p = 0.005) and 64 % (p = 0.004) less likely to be detected in winter than in summer. Tapeworm-infected mites were more likely to be detected from March to September when more mites were recovered from paddocks, whilst saliva antibody test-positive horses were least likely to occur in autumn. Horses that grazed for half a day compared to those that grazed for full days were less likely to be positive in the saliva test. The findings yielded new insights into the epidemiology of equine tapeworm and its intermediate host in the UK, and contribute valuable information to support evidence-based control programmes for this parasite.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145124730","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":"Ecological drivers of parasite genetic diversity: evidence for dilution effects in a single strongylid species infecting sympatric Bornean primates.","authors":"Kenneth Keuk, Symphorosa Sipangkui, Noor Haliza Hasan, Benoit Goossens, Munehiro Okamoto, Takashi Matsumoto, Andrew James Johnathan MacIntosh","doi":"10.1016/j.ijpara.2025.09.004","DOIUrl":"10.1016/j.ijpara.2025.09.004","url":null,"abstract":"<p><p>Biodiversity loss and emerging diseases threaten ecosystem and human health. Identifying ecological drivers of host-parasite dynamics in human-altered landscapes is crucial, including at the scale of parasite genetic diversity. We investigated genetic diversity and ecological drivers of gastrointestinal strongylid nematodes infecting a primate community in Sabah, Malaysian Borneo. We surveyed primates in the Lower Kinabatangan Wildlife Sanctuary, and used high-throughput sequencing (HTS) of ITS2 rDNA from 250 fecal samples (five out of ten sympatric primates). Through boat-surveys and remote sensing, we assessed habitat quality, host diversity, and density effects on parasite genetic alpha and beta diversity-i.e., sample amplicon sequence variant (ASV) richness, evenness and composition. Matching previous reports, HTS confirmed Oesophagostomum aculeatum as the sole strongylid species, exhibiting variable ASV diversity. Primate host diversity exerted a negative effect-a.k.a. a dilution effect-on O. aculeatum ASV richness during the wet season, controlling for strong seasonality. Effects of habitat quality and host density were inconsistent on ASV richness. No effect was found on ASV evenness. ASV composition varied by host species, season, and habitat quality, but not primate diversity or density. By demonstrating a local dilution effect at a small spatial and phylogenetic scale, our findings emphasize the importance of integrating ecological and molecular approaches. This study provides a baseline for future research on host-parasite co-evolution in Southeast Asian primates, ecological drivers of parasite genetic diversity, and insights into how phenomena like the diversity-disease relationship can operate across nested scales, with implications for disease emergence risks.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145124701","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":"Updates on subgenus Ixodes in the Mediterranean region: validity of Ixodes festai Rondelli, 1926, reinstatement of Ixodes tatei Arthur, 1959, and a new species closely related to Ixodes gibbosus Nuttall, 1916.","authors":"Sándor Hornok, Adem Keskin, Igor Uspensky, Jenő Kontschán, Nóra Takács, Paulina Lesiczka, Tim Warbroek, Tijs J M van den Bosch, Gergő Keve, Andor Pitó, Attila D Sándor","doi":"10.1016/j.ijpara.2025.09.002","DOIUrl":"10.1016/j.ijpara.2025.09.002","url":null,"abstract":"<p><p>The southern part of Europe is one of the most species-rich regions from the point of view of the genus and subgenus Ixodes. However, numerous unresolved or questionably interpreted issues exist in the context of tick species indigenous to Mediterranean countries, such as the validity of Ixodes festai, synonymy of Ixodes tatei with Ixodes eldaricus (never tested molecularly) or the haplotype heterogeneity of Ixodes gibbosus. In this study, 21 specimens of six tick species from the subgenus Ixodes were compared morphologically with high resolution digital microscopy and also analyzed with molecular-phylogenetic methods based on two mitochondrial genetic markers. The nymphs of I. eldaricus and I. tatei showed differences in the morphology of the scutum and basis capituli. Both the nymph and the females of I. festai could be distinguished from those of I. eldaricus, I. ventalloi and I. acuminatus. A female tick resembled I. gibbosus but was also different from this species, based on its descriptions. Analysis of phylogenetic relationships confirmed with moderate to strong support that all six species examined in this study represent different taxa of the subgenus Ixodes, including a previously unknown sister species to I. gibbosus. The latter is recognized and described here as a new species, Ixodes paragibbosus Hornok and Kontschán, sp. nov. Based on findings of this study, the tick species I. tatei Arthur, 1959 should be resurrected and reestablished. Morphological and phylogenetic comparisons performed here (including the first barcoding sequences of I. eldaricus and I. festai) confirm that the latter is a valid species, distinct from both I. eldaricus and I. ventalloi. For the differential diagnosis of the above species, the results highlight the importance of observing (among other structures) the auriculae, the internal spur of coxa I and the hypostome.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145113039","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":"Broad host specificity of Trichinella chanchalensis and minimal interspecific competition with T. nativa and T6 in naturally co-infected hosts.","authors":"Cody J Malone, N Jane Harms, Vladislav A Lobanov, W Brad Scandrett, Camila A Queiroz, Maarten J Voordouw, Thomas S Jung, Sarah E Parker, Emily J Jenkins","doi":"10.1016/j.ijpara.2025.09.001","DOIUrl":"10.1016/j.ijpara.2025.09.001","url":null,"abstract":"<p><p>Trichinella are muscle-dwelling parasitic nematodes that infect a wide range of vertebrate hosts, including humans. Trichinella chanchalensis is a newly recognized species that has been reported in wolverine (Gulo gulo). To investigate the host range of T. chanchalensis we examined the tongue and/or diaphragm from 125 wolverines, 34 red foxes (Vulpes vulpes), 23 Canada lynx (Lynx canadensis), 13 grey wolves (Canis lupus), 10 coyotes (Canis latrans), six black bears (Ursus americanus), one grizzly bear (Ursus arctos), and one polar bear (Ursus maritimus), from Yukon, Canada. Larvae were recovered from tissues by artificial digestion, quantified as larvae per gram (LPG), and genotyped using next-generation sequencing (NGS) on pools of larvae. The parasite intensity of three Trichinella species/genotypes (T. nativa, Trichinella T6, T. chanchalensis) in each sample was estimated by multiplying LPG and relative abundance. Trichinella larvae were detected in 74 % (158/213) of animals and prevalence ranged from 16.7 % in black bears to 86.4 % in wolverines. Median infection intensity was highest in wolverines (13.5 LPG) and lowest in lynx (1.2 LPG), and 92 % of hosts were co-infected with ≥ 2 Trichinella species/genotypes. The parasite intensity of Trichinella T6 was two times greater than T. nativa, and 17 times greater than T. chanchalensis. Trichinella chanchalensis was detected in three new host species including lynx, wolves, and a coyote. There was no significant interaction between Trichinella species/genotype and host species which suggests minimal host specificity. The parasite intensities of T. nativa and T6 were highly positively correlated, which suggests no competition and that infection with one species does not preclude infection by the other species. Our study demonstrates low host specificity and minimal interspecific competition among Trichinella larvae within muscles of naturally co-infected carnivore hosts.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145064613","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 transcriptomic analysis of the Whirling disease-resistant Gunnison River Rainbow Trout.","authors":"Abdullah A Gharamah, Renald J Legaspi, Elisabeth H Richardson, Eric R Fetherman, Katharine E Magor, Patrick C Hanington","doi":"10.1016/j.ijpara.2025.08.016","DOIUrl":"10.1016/j.ijpara.2025.08.016","url":null,"abstract":"<p><p>Whirling disease is a debilitating disease of Rainbow Trout caused by Myxobolus cerebralis. The parasite invasion leads to skeletal deformities, neurological impairment, and high mortality. Since its introduction to North America, M. cerebralis has severely impacted wild trout populations in several regions. In this study, we focus on a promising Whirling disease-resistant Rainbow Trout strain developed in the Gunnison River, Colorado. We analyzed the genomes and transcriptomes of this resistant strain at different time points after challenge with M. cerebralis. Signature selection analysis revealed several regions across the genome under selection, with the highest density found on chromosome 23. Several genes found in areas under selection are associated with neuron differentiation and nervous system development. Also, several immuno-genes were under selection, including several with relevance to the innate and adaptive immune response. The transcriptomic analysis revealed that the Gunnison River Rainbow Trout develops a comprehensive immune response after exposure to M. cerebralis. This is supported by the significant enrichment of specific immune response pathways, including differentiation and activation of B-cells and T-cells. These results suggest that certain immune pathways are likely to participate in building the Gunnison River Rainbow Trout's early, mid, and long-term immune response against M. cerebralis, while other pathways related to nervous system development may help juvenile fish survive the effects of Whirling disease. The transcriptomic analysis also reveals that more than half of the top 20 upregulated immune genes are components of the complement pathway. Notably, CD209 (DC-SIGN), a critical gene involved in antigen recognition and dendritic cell function, is among the most highly upregulated genes. The results also indicate the presence of a specific region on chromosome 9 in this strain, previously linked to resistance to this disease. This may explain this strain's strong disease resistance and survival capacity in natural environments.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145008206","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":"Sporogonic development of Hepatozoon felis in naturally infected Rhipicephalus turanicus and Rhipicephalus rutilus ticks and induction of sporocyst excystation by duodenal fluid.","authors":"Gad Baneth, Yaarit Nachum-Biala, Omer Revah, Harold Salant","doi":"10.1016/j.ijpara.2025.08.017","DOIUrl":"10.1016/j.ijpara.2025.08.017","url":null,"abstract":"<p><p>Hepatozoon felis is a protozoan parasite reported in Europe, Africa, Asia and the Americas with infection rates ranging from 4 % to 30 % in domestic cats in Mediterranean countries. Although the parasite was described in 1908, its arthropod vector has not been reported to date. Ticks removed from cats were dissected to prepare hemocoel smears with the aim of identifying the sporogonic life stages of H. felis. Light and live video microscopy were used to visualize these stages and PCR followed by DNA sequencing served to verify the Hepatozoon sp. found and to morphologically and molecularly define the tick species examined. Of 42 adult ticks, 30 were Rhipicephalus turanicus, eight Haemaphysalis adleri, three Rhipicephalus rutilus and one was Rhipicephalus secundus. Sporocysts and oocysts of H. felis verified by PCR were present in eleven R. turanicus and two R. rutilus ticks (31 %). The sporocysts of H. felis were round and each sporocyst harbored 9-11 sporozoites. Developing and mature H. felis oocysts, sporocysts and sporozoites were measured and described morphologically. Experiments to study the excystation of sporocysts and release of infectious sporozoites indicated that combined body temperature of 38.5 ℃ and contact with duodenal fluids are required for activation of sporozoites and excystation as viewed by live imaging. Sporocysts excysted within 250 s of exposure to duodenal fluid and excystation occurred significantly more frequently in the sporocysts that were incubated at 38.5 °C and exposed to duodenal fluid compared to those only incubated at 38.5 °C (P = 0.0001). In conclusion, sporogony of H. felis was described in R. turanicus and R. rutilus filling a gap in knowledge on the life cycle of this parasite whose arthropod vectors were unknown. Induction of H. felis sporocyst excystation required both body temperature and contact with duodenal fluid, simulating conditions met when the parasite reaches the vertebrate host's small intestine.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000419","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":"When can multiple parasites with complex life cycles coexist under conflicts of host manipulation?","authors":"Chih-Wei Wang, Hsuan-Wien Chen, Takuya Sato, Takefumi Nakazawa","doi":"10.1016/j.ijpara.2025.08.012","DOIUrl":"10.1016/j.ijpara.2025.08.012","url":null,"abstract":"<p><p>Parasites are diverse and play crucial roles in ecosystems, yet mechanisms underlying their diversity remain poorly understood. Many parasites have complex life cycles, manipulating their hosts to facilitate transition through inter-host trophic interactions. When multiple parasites share a common intermediate host but transition to different definitive hosts, they face two conflicts in host manipulation strategies. First, host manipulation may increase predation by non-host predators, leading to \"dead-ends.\" Second, interactions among parasites may complicate host manipulation in a co-infected intermediate host. To explore how host-manipulating parasites compete and coexist under these conflicts, we developed a mathematical model describing population dynamics of two parasites, one intermediate host (prey), and two definitive hosts (predators). The competitive exclusion principle predicts that the two definitive hosts (and thus their parasites) cannot coexist due to competition for the intermediate host. However, our results show that host-manipulating parasites can alter this outcome. We identified three conditions that promote parasite coexistence: (i) the parasite infecting the competitively inferior predator is more prone to dead-ends as a result of adopting a target-generic host manipulation strategy, (ii) co-infected intermediate hosts are manipulated so that predation by the competitively superior predator decreases, whereas predation by the competitively inferior predator increases, and (iii) host-parasite community dynamics exhibit limited fluctuations. Future studies are encouraged to evaluate the likelihood that these conditions are met. Furthermore, we found that alternative states can emerge across a broad parameter space, suggesting potential regime shifts in their community composition. These findings provide novel insights into the mechanisms underlying parasite diversity and its fragility, laying the groundwork for future research on more complex scenarios.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000459","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":"Are there 16 species of brown dog ticks? Phylogenies from 60 entire mitochondrial genomes and 162 cox1 sequences reveal 16 species-level clades in the Rhipicephalus (Rhipicephalus) sanguineus group☆☆","authors":"Samuel Kelava ,&nbsp;Ryo Nakao ,&nbsp;Ben J. Mans ,&nbsp;Mingeun Cho ,&nbsp;Kynan B.T. Mateo ,&nbsp;Dmitry A. Apanaskevich ,&nbsp;Renfu Shao ,&nbsp;Alexander W. Gofton ,&nbsp;Ernest J.M. Teo ,&nbsp;Takuya Ito ,&nbsp;Dayana Barker ,&nbsp;Stephen C. Barker","doi":"10.1016/j.ijpara.2025.04.016","DOIUrl":"10.1016/j.ijpara.2025.04.016","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The &lt;em&gt;Rhipicephalus sanguineus&lt;/em&gt; group, the brown dog ticks, are cosmopolitan and doubtless the most important ticks of domestic dogs, clinically and economically. Despite four decades of taxonomic enquiry with nucleotide sequences and morphology, the taxonomy of the &lt;em&gt;R. sanguineus&lt;/em&gt; group is confused, even chaotic. We provide 13 new mitochondrial (mt) genomes and internal transcribed spacer 2 (&lt;em&gt;ITS2&lt;/em&gt;) sequences from nine localities in Australia, Israel and Japan. We inferred phylogenetic trees from 10 mt protein-coding genes (9,514 bp), as well as partial &lt;em&gt;cox1&lt;/em&gt;, &lt;em&gt;ITS2,&lt;/em&gt; 12S, and 16S rRNA genes, to resolve to common clades the &gt;2,000 nucleotide sequences in GenBank from the &lt;em&gt;R. sanguineus&lt;/em&gt; group. Then we applied three species delimitation protocols to 60 entire mt genomes (ca. 15,000 bp) and 162 partial &lt;em&gt;cox1&lt;/em&gt; sequences (472 bp): Automatic Barcode Gap discovery, Assemble Species by Automatic Partitioning, and Poisson Tree Process. We considered pairwise genetic differences and Tamura-Nei genetic distances among 60 entire mt genomes and 162 partial &lt;em&gt;cox1&lt;/em&gt; sequences. We found 16 species-level clades (clades A to P) that we hypothesise represent at least 16 species in the &lt;em&gt;R. sanguineus&lt;/em&gt; group. These clades had intra-clade differences of &lt;3.8% (entire mt genomes) and &lt;5.1% (partial &lt;em&gt;cox1&lt;/em&gt;) whereas the inter-clade differences were &gt;7.7% (entire mt genomes) and &gt;4.5% (partial &lt;em&gt;cox1&lt;/em&gt;). We assigned the species names &lt;em&gt;Rhipicephalus linnaei&lt;/em&gt; (Audouin, 1826), &lt;em&gt;Rhipicephalus rutilus&lt;/em&gt; (Koch, 1844), &lt;em&gt;Rhipicephalus secundus&lt;/em&gt; (Feldman-Muhsam, 1952) and &lt;em&gt;R. sanguineus&lt;/em&gt; (Latreille, 1806) to clades A, C, D, and K, respectively. And we hypothesise that the names &lt;em&gt;Rhipicephalus camicasi&lt;/em&gt; (Morel, Mouchet &amp; Rodhain, 1976), &lt;em&gt;Rhipicephalus turanicus&lt;/em&gt; (Pomerantsev, 1940), &lt;em&gt;Rhipicephalus guilhoni&lt;/em&gt; (Morel &amp; Vassilades, 1963), &lt;em&gt;Rhipicephalus sulcatus&lt;/em&gt; (Neumann, 1908), &lt;em&gt;Rhipicephalus rossicus&lt;/em&gt; (Yakimov &amp; Kol-Yakimova, 1911), &lt;em&gt;Rhipicephalus pumilio&lt;/em&gt; (Schulze, 1935) and &lt;em&gt;Rhipicephalus pusillus&lt;/em&gt; (Gil Collado, 1936) apply to clades B, E, H, J, M, N and O, respectively. The newly described &lt;em&gt;Rhipicephalus hibericus&lt;/em&gt; (Millán, Rodriguez-Pastor &amp; Estrada-Peña, 2024) was genetically indistinguishable from &lt;em&gt;R. sanguineus&lt;/em&gt; in clade K and thus is a synonym of &lt;em&gt;R. sanguineus&lt;/em&gt;. We could not assign names to clades F (USA, Hungary), I (India, Pakistan), L (Nigeria), G (China, Kazakhstan), and P (Cameroon): some or all of these five clades may be new species in the &lt;em&gt;R. sanguineus&lt;/em&gt; group. Our haplotype network of partial mt genes (&lt;em&gt;cox1, cytb&lt;/em&gt; and &lt;em&gt;nad2&lt;/em&gt;) revealed much genetic similarity among geographically distant populations of &lt;em&gt;R. linnaei&lt;/em&gt;. This indicates recent dispersal, likely originating in Africa or the Middle East, since African populations were ","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"55 11","pages":"Pages 581-594"},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143982241","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}