International journal for parasitology最新文献

{"title":"The effect of gregarine (Apicomplexa) colonisation on the functional response of the amphipod host","authors":"Heather J. Knight ,&nbsp;Kevin O. McKinley ,&nbsp;Anastasios D. Tsaousis ,&nbsp;Jennifer A. Dodd ,&nbsp;Sonja Rückert","doi":"10.1016/j.ijpara.2025.10.002","DOIUrl":"10.1016/j.ijpara.2025.10.002","url":null,"abstract":"<div><div>Gregarines are a notably understudied but widespread group of protists that colonise aquatic and terrestrial invertebrates. This limited understanding of gregarines and their interactions with their hosts results partly from the absence of established culturing techniques and our understanding therefore has heavily relied on field collections. This study utilised for the first time cultured <em>Gammarus pulex</em> populations and comparative functional response models to explore the effects of gregarine colonisation on the host’s consumption of Chironomid prey. This study shows that both positive and negative <em>G. pulex</em> displayed a Type II functional response. There were no statistical differences in the functional response parameters between the two groups. These results suggest that, under the study conditions, gregarines may function as commensal symbionts within their <em>G. pulex</em> host. This is consistent with growing evidence for gregarines acting across a range of symbiotic roles within their hosts. These findings provide insight into the role of gregarines in <em>G. pulex</em>, an invertebrate species frequently used for field- and lab-based experiments, contributing to the evidence of the complex and varied gregarine host-symbiont interactions.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104742"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312814","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":"Anisakid nematodes in skates (Chondrichthyes: Rajiformes) along a depth gradient: do bathymetry and host size influence the presence of zoonotic parasites?","authors":"Manuel M. Irigoitia ,&nbsp;Marialetizia Palomba ,&nbsp;Paola E. Braicovich ,&nbsp;María Paz Gutiérrez ,&nbsp;Delfina Canel ,&nbsp;Simonetta Mattiucci ,&nbsp;Juan T. Timi","doi":"10.1016/j.ijpara.2025.10.007","DOIUrl":"10.1016/j.ijpara.2025.10.007","url":null,"abstract":"<div><div>Some species of Anisakidae are known to cause human anisakidosis due to ingestion of seafood containing larvae L3. Although cartilaginous fishes are infrequently reported as hosts for anisakids, they could play a role in their transmission to definitive hosts. The occurrence and level of infestation by anisakids on 18 species of skates were analysed, based on a sample of 676 specimens. A total of 1692 worms were recorded; the morphologic and genetic analysis of mDNA cox2 gene, confirmed the presence of <em>Anisakis pegreffii</em>, <em>A. berlandi</em> and <em>Phocanema cattani</em>, whose presence and burdens varied among the species of skates examined. The models generated from prevalence and mean abundance data showed that both bathymetric distribution and length of skates influence the anisakid load in the host species studied. <em>Phocanema cattani</em> prevailed in coastal skates, whereas <em>Anisakis</em> spp. were more common at greater depths. Indeed, the molecular analysis showed that <em>A. pegreffii</em> was most frequent in skates species inhabiting coastal to middle shelf waters, while <em>A. berlandi</em> was relatively more common in skate species living in deeper waters. The knowledge of the epidemiology of anisakids in the Southwestern Atlantic is still incipient, particularly those studies employing molecular approaches. Despite this study being geographically limited and restricted to a closely related group of hosts, the observed patterns would be extensive to other latitudes and species. This would contribute to a more comprehensive understanding of the ecology of an emerging zoonoses, which have implications for human health and international trade; even more under a global warming scenario.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104747"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145431482","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":"Glycan remodelling of live adult Schistosoma mansoni worms by chemical inhibition of α-mannosidases","authors":"Eleonore B. Kuhlemaijer ,&nbsp;Tom Veldhuizen ,&nbsp;Isabella A. van Hulst ,&nbsp;Tessa Liesker ,&nbsp;Benjamin J. Hulme ,&nbsp;Josephine E. Forde-Thomas ,&nbsp;Gabriel Rinaldi ,&nbsp;Karl F. Hoffmann ,&nbsp;Angela van Diepen ,&nbsp;Cornelis H. Hokke","doi":"10.1016/j.ijpara.2025.11.002","DOIUrl":"10.1016/j.ijpara.2025.11.002","url":null,"abstract":"<div><div>Schistosomiasis is a neglected tropical disease affecting over 250 million people worldwide. <em>Schistosoma</em> parasites can survive in the human host for years due to their capability to evade and modulate host immune responses. Glycans and glycoproteins produced by schistosomes are thought to play an important role in shaping parasite-host interactions. In addition, N-linked glycans are vital post-translational protein modifications involved in fundamental cellular and developmental processes like protein folding and cell–cell interactions. In this study, we generated live <em>Schistosoma mansoni</em> adult worms with altered N-glycosylation using the α-mannosidase inhibitors kifunensine and swainsonine, compounds which restrict complex N-glycan processing thereby preventing complex N-glycan formation. We show that <em>ex vivo</em> cultured adult schistosomes display a stable N-glycosylation profile during two weeks of culture characterised by roughly one-third mannose and two-third complex glycans. Inhibition of α-mannosidases during culture resulted in a modified N-glycan profile over time: kifunensine-treated parasites were found to contain 76% mannose N-glycans, while swainsonine-treated parasites showed a strongly increased abundance of hybrid glycans and (fucosylated) mannose glycans. These observations are in line with the expected effect of the inhibitors on endoplasmic reticulum and Golgi α-mannosidases, respectively. Additionally, we examined the N-glycan composition of the worm tegument, a major parasitic structure found at the parasite-host interface. The tegument contained mainly complex N-glycans, often carrying the GalNAcβ1-4GlcNAc (LacdiNAc, LDN) motif, different from the rest of the schistosome body. Again, α-mannosidase inhibition changed the N-glycosylation profile of the tegument, similarly as observed for whole worms. No negative effects of any of the treatments on parasite motility or morphology were observed, indicating that the basic biology of the worms in culture was not affected by these N-glycosylation changes. Our results demonstrate the feasibility of creating a live glyco-remodelled parasite, setting the scene for studying functional parasite glycobiology and glycan-mediated effects in host-parasite interaction.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104750"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145573884","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":"Analysis of Oesophagostomum dentatum excretory-secretory molecules and extracellular vesicles uncovers a repertoire of microRNAs shared with A. Suum and T. Suis and ES containing Paz and Piwi domain proteins implicated in RNAi signaling","authors":"Maibritt Mardahl ,&nbsp;Eline P. Hansen ,&nbsp;Bastian Fromm ,&nbsp;Anne Borup ,&nbsp;Bradley Whitehead ,&nbsp;Anders T. Boysen ,&nbsp;Allan Stensballe ,&nbsp;Kasper L. Andersen ,&nbsp;Andrew R. Williams ,&nbsp;Aaron R. Jex ,&nbsp;Robin B. Gasser ,&nbsp;Merete Fredholm ,&nbsp;Stig Milan Thamsborg ,&nbsp;Peter Nejsum","doi":"10.1016/j.ijpara.2025.10.006","DOIUrl":"10.1016/j.ijpara.2025.10.006","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Soil-transmitted helminths (STH) are prevalent in pigs, with the nodular worm, &lt;em&gt;Oesophagostomum dentatum,&lt;/em&gt; causing a chronic infection that affects animal welfare and productivity. Unlike the two other dominant soil-transmitted helminths of pigs, &lt;em&gt;Ascaris suum&lt;/em&gt; and &lt;em&gt;Trichuris suis&lt;/em&gt;, &lt;em&gt;O. dentatum&lt;/em&gt; promotes immune responses that deviate from the normal parasite-induced type 2 helper (Th2) response causing long-term infection with minimally acquired immunity. &lt;em&gt;O. dentatum&lt;/em&gt; induces a proinflammatory Type 1 helper(Th1)-like response followed by a delayed non-protective Th2 response. The mechanism underlying this disparate response is unclear. Intestinal parasites interact with the host via excreted-secreted molecules and here we investigate the protein and microRNA content of the infectious L3 and adult stage of &lt;em&gt;O. dentatum&lt;/em&gt; focusing particularly on identifying the content of extracellular vesicles (EVs). Using Cryo-EM, nanoparticle tracking analysis and silver staining, we confirmed the presence of EVs in adult worm ES. Proteomic analysis revealed prototypical ES proteins, including SCP-like proteins, transthyretin-like proteins, and peptidases, proteases and hydrolases. Interestingly, a DEAD-Box RNA helicase was found unique to EVs, while a Paz domain protein and a Piwi domain protein was found in the adult worm ES that shows sequence similarity to these domains in the exWAGO protein found in &lt;em&gt;H. bakeri&lt;/em&gt; EVs. Pathway enrichment analyses revealed proteins involved in nutrient metabolism, and the proteasome. To understand which microRNAs &lt;em&gt;O. dentatum&lt;/em&gt; parasites secrete, we annotated the microRNA complement from small RNA-seq libraries from the ES, EVs and EV-depleted SN using microRNA prediction tools (MirMachine and MirMiner). We identified 44 precursor microRNAs and 88 mature microRNAs in the &lt;em&gt;O. dentatum&lt;/em&gt; ES microRNA complement. Quantification revealed 22, 44, and 48 mature microRNAs in L3 EVs, adult EVs and adult SN, respectively, with substantial overlap between L3 and adult EVs (n = 22, 37 % of shared set) and between adult EVs and SN (n = 58, 75 % of shared set). Differential analysis identified 11 microRNAs significantly differentially abundant between sample types. To explore potential conservation of EV microRNAs across nematode species, we here, for the first time, compare the microRNA family profiles of &lt;em&gt;O. dentatum&lt;/em&gt; adult EVs with those of &lt;em&gt;A. suum&lt;/em&gt; and &lt;em&gt;T. suis&lt;/em&gt;. We found eight shared microRNA families that are known to be highly abundant in the worms themselves: LET-7, MIR-10, MIR-34, MIR-9, MIR-305, MIR-54, MIR-216, and MIR-750. Their diverging microRNA profiles might underlie their species-specific differences in parasitism. Taken together, this study expands the current knowledge of excretory-secretory molecules in non-model parasitic nematodes and confirms the presence of proteins involved in RNAi processing in the ES of the clade V nemato","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104746"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145421788","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":"Evaluation of a lateral flow test to diagnose liver fluke in cattle and sheep","authors":"Tessa R. Walsh ,&nbsp;Joseph W. Angell ,&nbsp;Andrew Bentham ,&nbsp;Eleanor Bentley ,&nbsp;Helen Clough ,&nbsp;John Graham-Brown ,&nbsp;Alison Howell ,&nbsp;Sonja Steinke ,&nbsp;Alison Wakeham ,&nbsp;Diana J.L. Williams","doi":"10.1016/j.ijpara.2025.11.004","DOIUrl":"10.1016/j.ijpara.2025.11.004","url":null,"abstract":"<div><div><em>Fasciola hepatica</em> (the liver fluke) is an important parasite of cattle and sheep globally. Current diagnostic tests are laboratory based, which involve costs for sample collection and time taken for results to be returned. This can discourage farmers from engaging with the industry message to test before treating. Treatment in the absence of a diagnosis can contribute to the development of resistance to anthelmintics. We have developed a lateral flow test (LFT) to detect antibodies to fluke in whole blood, which can be used on-farm to detect exposure in cattle and sheep within 10 min. LFT performance was evaluated though on-farm trials sampling 10 sheep on 24 farms, and where possible, up to 10 cattle. Results were compared to those obtained with an in-house antibody detection ELISA. Linear regression analysis showed a positive correlation between LFT and ELISA results. Bayesian analysis assuming no gold standard indicated that the LFT had a sensitivity (Se) of 77 % (95 % Credible Interval [CI] 61–91 %) and specificity (Sp) of 80 % (CI 70–89 %) in cattle and 67 % Se (CI 47–94 %) and 71 % Sp (CI 62–82 %) for sheep. Sub-setting for first season lambs gave 96 % Se (CI 85–100 %) and 74 % Sp (CI 65–84 %). A group interview with the farmers who participated in on-farm trials indicated they found the LFT easy to use and thought it would be a useful tool to guide treatment decisions. The LFT will enable farmers to better engage with fluke management on their farms and encourage appropriate use of anthelmintics.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104752"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145581651","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":"Ambient temperature storage in DESS supports molecular studies of benzimidazole resistance from canine hookworm eggs","authors":"Yi-Jou Chen ,&nbsp;Vanessa Li ,&nbsp;Michelle Suwandy ,&nbsp;Ioana Bianca Mitrea ,&nbsp;Douglas Hayward ,&nbsp;Susan Jaensch ,&nbsp;Emily Kate Francis ,&nbsp;Jan Šlapeta","doi":"10.1016/j.ijpara.2025.10.005","DOIUrl":"10.1016/j.ijpara.2025.10.005","url":null,"abstract":"<div><div>Emerging benzimidazole resistance in canine hookworms poses a growing concern for veterinary and public health. Molecular diagnostics targeting β-tubulin gene mutations are essential for resistance surveillance but traditionally rely on refrigerated faecal samples. This study evaluates dimethyl sulfoxide, EDTA, and saturated NaCl (DESS) as a room-temperature preservation medium for canine faeces. Using ITS-2 rDNA and isotype-1 β-tubulin gene (<em>tubb-1</em>) amplicon metabarcoding, we compared DNA integrity and diagnostic performance of DESS-preserved samples (4, 28, and 106 days) to refrigerated controls. No significant differences in PCR amplification or sequencing outcomes were observed. DESS enabled reliable detection of hookworm species and resistance-associated SNPs, including F167Y in <em>tubb-1</em>, with mutation frequencies consistent across treatments. Therefore, DESS can preserve samples from remote settings without cold chain logistics. Our findings validate DESS as a robust alternative for sample collection for molecular parasitology, facilitating expanded surveillance of anthelmintic resistance in field conditions.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104745"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145367910","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":"Unveiling hidden parasite diversity: Long-read mitogenomics in Eimeriidae and Haemosporida (Eukaryota: Apicomplexa)","authors":"Peihang Hong ,&nbsp;Sijia Yu ,&nbsp;Hau-You Tzeng ,&nbsp;Tzu-Chun Chou ,&nbsp;Hsin-Yu Lin ,&nbsp;Tung Yee Shiu ,&nbsp;Yu-Hsuan Lin ,&nbsp;Cheng-You Lu ,&nbsp;Chao-Min Wang ,&nbsp;Cheng-Hung Lai ,&nbsp;Shyun Chou ,&nbsp;Toshihiro Tokiwa","doi":"10.1016/j.ijpara.2025.104764","DOIUrl":"10.1016/j.ijpara.2025.104764","url":null,"abstract":"<div><div>Mitochondrial genomes of apicomplexan parasites exhibit remarkable structural diversity, ranging from highly reduced linear molecules to circular-mapping concatemers, yet their full characterization has been hindered by technical limitations in resolving complex infections. This study establishes a novel integrated workflow combining one-step PCR amplification with Oxford Nanopore Technologies (ONT) to sequence complete mitochondrial genomes from Eimeriidae and Haemosporida parasites. Successful assembly of 29 high-quality mitogenomes (12 Eimeriidae, 17 Haemosporida) from 15 samples, demonstrating the method’s sensitivity. Comparative analyses revealed cryptic mixed/co-infections in 11 samples that were undetectable by Sanger sequencing, highlighting ONT’s superior resolution for uncovering true parasite diversity. Phylogenomic reconstruction using the largest Eimeriidae dataset to date confirmed the monophyly of passeriform <em>Isospora</em> and identified a basal position for a novel <em>Caryospora</em> lineage from <em>Ptyas major</em>. In Haemosporida, analysis of 202 mitogenomes revealed non-monophyletic familial relationships. Selection analyses indicated predominant purifying selection in mitochondrial protein-coding genes of Eimeriidae. Our findings underscore the utility of long-read mitogenomics in elucidating complex infection dynamics and provide a scalable framework for biodiversity surveys of understudied apicomplexans parasites, with implications for understanding their evolutionary ecology and host-parasite interactions.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 5","pages":"Article 104764"},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145878267","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 novel Toxoplasma gondii thioredoxin (TgTrx1) is important for parasite fitness and virulence","authors":"Zhi-Wei Zhang ,&nbsp;Meng Wang ,&nbsp;Ting-Ting Li ,&nbsp;Hany M. Elsheikha ,&nbsp;Xiao-Jing Wu ,&nbsp;Li-Xiu Sun ,&nbsp;Bao-Quan Fu ,&nbsp;Xing-Quan Zhu ,&nbsp;Jin-Lei Wang","doi":"10.1016/j.ijpara.2025.08.015","DOIUrl":"10.1016/j.ijpara.2025.08.015","url":null,"abstract":"<div><div>The protozoan parasite <em>Toxoplasma gondii</em> relies on antioxidant proteins and systems to protect against the host′s immune responses and to neutralize free radicals produced by its own metabolism. In this study, we identified and characterized a new thioredoxin protein, TgTrx1, which is mainly found in the cytoplasm of <em>T. gondii</em> tachyzoites and contains a conserved -CXXC- catalytic motif. Using CRISPR-Cas9 gene editing, we disrupted the Tg<em>Trx1</em> gene to generate a knockout strain (RHΔ<em>trx1</em>) and studied the effect of gene loss on various aspects of the infection process. RHΔ<em>trx1</em> parasites showed a marked reduction in their ability to invade host cells, secrete microneme proteins, replicate intracellularly, egress from host cells, and tolerate oxidative stress. They also displayed abnormal mitochondrial morphology and asynchronous cell division. Transcriptomic analysis revealed significant changes in the expression of genes involved in oxidative stress response and bradyzoite differentiation. Mice injected intraperitoneally with 10⁶ RHΔ<em>trx1</em> tachyzoites showed no clinical symptoms. However, the immunity induced by these attenuated tachyzoites conferred only partial protection against subsequent acute and chronic <em>T. gondii</em> infections. This limited protective effect is likely related to the parasite′s impaired replication, which may lead to rapid clearance by the host immune system and insufficient antigenic stimulation to elicit a fully protective immune response. These findings establish TgTrx1 as a multifunctional redox protein important for <em>T. gondii</em> survival, redox balance, synchronous cell division, and virulence.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 3","pages":"Article 104727"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953043","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,&nbsp;Yaarit Nachum-Biala,&nbsp;Omer Revah,&nbsp;Harold Salant","doi":"10.1016/j.ijpara.2025.08.017","DOIUrl":"10.1016/j.ijpara.2025.08.017","url":null,"abstract":"<div><div><em>Hepatozoon felis</em> 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 <em>H. felis</em>. Light and live video microscopy were used to visualize these stages and PCR followed by DNA sequencing served to verify the <em>Hepatozoon</em> sp. found and to morphologically and molecularly define the tick species examined. Of 42 adult ticks, 30 were <em>Rhipicephalus turanicus</em>, eight <em>Haemaphysalis adleri</em>, three <em>Rhipicephalus rutilus</em> and one was <em>Rhipicephalus secundus</em>. Sporocysts and oocysts of <em>H. felis</em> verified by PCR were present in eleven <em>R. turanicus</em> and two <em>R. rutilus</em> ticks (31 %). The sporocysts of <em>H. felis</em> were round and each sporocyst harbored 9–11 sporozoites. Developing and mature <em>H. felis</em> 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 (<em>P</em> = 0.0001). In conclusion, sporogony of <em>H. felis</em> was described in <em>R. turanicus</em> and <em>R. rutilus</em> filling a gap in knowledge on the life cycle of this parasite whose arthropod vectors were unknown. Induction of <em>H. felis</em> sporocyst excystation required both body temperature and contact with duodenal fluid, simulating conditions met when the parasite reaches the vertebrate host’s small intestine.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 3","pages":"Article 104729"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","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":"Unexpected intron plasticity and trans-splicing capability suggest spliceosome diversification in the evolutionarily divergent protozoan parasite Trichomonas vaginalis","authors":"Khatima Mohammadi,&nbsp;Kim Ciennis Houang,&nbsp;Shuqi Edward Wang,&nbsp;John Hunt,&nbsp;Carol Wang,&nbsp;Augusto Simoes-Barbosa","doi":"10.1016/j.ijpara.2025.08.011","DOIUrl":"10.1016/j.ijpara.2025.08.011","url":null,"abstract":"<div><div>Spliceosomal introns, distinctive features of eukaryotic genomes, are non-coding sequences excised from pre-mRNAs by the spliceosome, contributing to genome evolution and protein diversity. Although spliceosomal introns have been characterised in several eukaryotic lineages, their origin and evolution remain unresolved. The protozoan parasite <em>Trichomonas vaginalis</em> is a highly divergent eukaryote with a large genome and a rich gene repertoire, but apparently few spliceosomal introns. Following from the discovery of a group of unusually short introns in this organism, we developed here a fluorescent reporter system and combined with extensive mutagenesis to dissect the splicing requirements of these short introns, comparing them to conventional long introns. We found that short introns have reasonable but limited flexibility in their length, including extreme juxtaposition of the branch site and the 3′ splice site, which, to our knowledge, is an unprecedented feature among eukaryotic introns. Additionally, they clearly exhibit splice signal features that distinguish them from long introns, including a highly degenerate 5′ splice site. Remarkably, we found that <em>T. vaginalis</em> is capable of <em>trans</em>-splicing an endogenous intron that was deliberately split and a naturally split intron from <em>Giardia lamblia</em>, a more distant diplomonad within the same Metamonada supergroup. Collectively, our findings highlight the evolutionary plasticity of RNA splicing systems in divergent eukaryotes, offering new perspectives on splicing mechanisms by the spliceosome.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"56 3","pages":"Article 104723"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953048","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}