Parasitology International最新文献

{"title":"In vivo efficacy of novel phosphoethanolamine methyltransferase inhibitors against Haemonchus contortus in a jird (Meriones unguiculatus) model","authors":"Leonor Sicalo Gianechini ,&nbsp;Xuejin Zhang ,&nbsp;Kun Li ,&nbsp;William H. Witola ,&nbsp;Ray M. Kaplan","doi":"10.1016/j.parint.2025.103054","DOIUrl":"10.1016/j.parint.2025.103054","url":null,"abstract":"<div><div>Anthelmintic resistance (AR) presents a significant challenge to the treatment of parasites in veterinary medicine, and is emerging as a growing concern in human medicine. Despite the pressing demand for compounds with novel mechanisms of action, the introduction of new anthelmintics to the market has been scarce. In this study, we investigated the <em>in vivo</em> efficacy of compounds previously demonstrated to be inhibitors of phosphoethanolamine methyltransferases (PMTs), enzymes that are highly conserved among parasitic nematodes and represent a novel drug target. Inhibition of PMT enzymes disrupts phosphocholine biosynthesis, which is crucial for parasite viability. This pathway is essential to nematodes and is not present in mammals, making it an attractive and highly selective drug target. Based on previous results obtained from <em>in vitro</em> screenings against both drug-susceptible and multidrug-resistant (MDR) <em>Haemonchus contortus</em>, three candidate compounds with potent <em>in vitro</em> activity were selected for use in a pilot <em>in vivo</em> study. Here, we employed the jird (<em>Meriones unguiculatus</em>) – <em>H. contortus</em> model. The dosing regimens used were selected based on available toxicological data, but since pharmacokinetic-pharmacodynamic (PKPD) profiles of these compounds are not known, dosing regimens were not optimized. As this was a pilot study, small groups of animals were used. Relatively high reductions in worm counts were achieved, ranging from 53.5 to 72.6 %, and for two of the three compounds this reduction was statistically significant (<em>P</em> = 0.008, <em>P</em> = 0.025). These findings further support PMT enzymes as viable drug targets in parasitic nematodes and highlight the need for PKPD studies. Optimizing dosing regimens and exploring synergistic activity could enhance efficacy, advancing the development of novel anthelmintics.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103054"},"PeriodicalIF":1.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the vector potential of deer keds Lipoptena fortisetosa for selected pathogens in Hokkaido sika deer (Cervus nippon yesoensis)","authors":"Kotaro Shimizu ,&nbsp;Michito Shimozuru ,&nbsp;Masami Yamanaka ,&nbsp;Genta Ito ,&nbsp;Ryo Nakao ,&nbsp;Toshio Tsubota","doi":"10.1016/j.parint.2025.103053","DOIUrl":"10.1016/j.parint.2025.103053","url":null,"abstract":"<div><div>Deer keds (<em>Lipoptena fortisetosa</em>) are hematophagous insects that parasitize various ungulates, including Hokkaido sika deer (<em>Cervus nippon yesoensis</em>). Although deer keds are potential vectors for several pathogens, their role in disease transmission in Japan remains unclear. This study aimed to evaluate the potential of L. <em>fortisetosa</em> as a vector for selected pathogens in sika deer. Blood samples were collected from 32 sika deer and 149 deer keds (64 from deer and 85 from the environment) from the Rusha area of the Shiretoko Peninsula, Hokkaido, Japan. Nested PCRs and sequencing were performed to detect 18S rRNA gene of <em>Theileria</em> sp. Thrivae, 16S rRNA gene of <em>Anaplasma</em> sp. AP-sd (AP-sd), and flagellin B gene of <em>Borrelia</em> sp. in deer and deer keds. In sika deer, the infection rate was 84 % for <em>Theileria</em> sp. Thrivae, 75 % of AP-sd, and 3 % of <em>Borrelia</em> sp. The prevalence in deer keds collected from deer was 62 % for <em>Theileria</em> sp. Thrivae, 2 % AP-sd, and 1 % <em>Borrelia</em> sp. No pathogens were detected in nonparasitic deer keds captured from the environment. Notably, <em>Theileria</em> sp. Thrivae and AP-sd were detected in deer keds collected from PCR-negative sika deer, suggesting that deer keds acquired pathogens from a previously infested host. The absence of pathogens in non-parasitized deer keds suggests that they do not play as a biological vector for the tested pathogens. This study suggests a potential role for L. <em>fortisetosa</em> as a mechanical vector, emphasizing the need for additional experiments, including infection studies.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103053"},"PeriodicalIF":1.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143483881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-density Plasmodium falciparum infection: “Even a parasite will turn”","authors":"Wataru Kagaya","doi":"10.1016/j.parint.2025.103052","DOIUrl":"10.1016/j.parint.2025.103052","url":null,"abstract":"<div><div>As global malaria control and elimination efforts have resulted in the suppression of <em>Plasmodium falciparum</em> infections, low-density <em>Plasmodium falciparum</em> infections present a significant challenge. These infections, frequently characterized as “submicroscopic” or “asymptomatic”, contribute to the persistent transmission in endemic regions. Recent advancements in molecular diagnostic methodologies have enhanced the detection of these infections and elucidated the nature of previously unrecognized infections. These infections harbor smaller populations of parasites; however, the risk of disease progression and transmission remains substantial. The observed infections could be an alternative survival mechanism of this parasite. Thus, control measures should be redesigned to address these infections, rather than merely expanding the current tools. This review provides an overview of the issues surrounding the detection and monitoring of these infections and their importance for infected individuals and populations, with further emphasis on control measures for malaria elimination.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103052"},"PeriodicalIF":1.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple calcified neurocysticercosis with several and repetitive episodes of perilesional edema: A case report","authors":"Carlos Alejandro Tellez-Arellano ,&nbsp;Polet Juárez-Ortiz ,&nbsp;Roger Carrillo-Mezo ,&nbsp;Agnès Fleury","doi":"10.1016/j.parint.2025.103048","DOIUrl":"10.1016/j.parint.2025.103048","url":null,"abstract":"<div><div>Calcified neurocysticercosis, the final stage of the disease, was until recently regarded as residual inactive scarring, with no clinical relevance in most cases. However, episodes of inflammatory reaction around calcifications associated with clinical symptoms have recently been described. We report here the 20-year radiological follow-up of a patient presenting 16 calcifications with multiple episodes of asynchronous inflammatory phenomena around several of them, not always associated with clinical symptomatology. This case is unique, showing the possibility of chronicity of this phenomenon, and the need to better understand the factors involved in determining the best management.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103048"},"PeriodicalIF":1.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular phylogeny by Bayesian analysis and description of a new species of Henneguya, a parasitic cnidarian from Astyanax bimaculatus (Linnaeus, 1758) (Characiformes: Acestrorhamphidae) in Caatinga: A biome with neglected biodiversity data","authors":"Maurício Jorge,&nbsp;Patrick Delgado Mathews,&nbsp;Diego Henrique Mirandola Dias Vieira,&nbsp;Reinaldo José da Silva","doi":"10.1016/j.parint.2025.103049","DOIUrl":"10.1016/j.parint.2025.103049","url":null,"abstract":"<div><div>Myxozoans are cnidarian parasites with a worldwide distribution and represent some of the most spectacular examples of parasite radiation. Based on an integrative taxonomic approach that includes spore morphology and molecular data, as well as other phenotypic characters such as host specificity, a new myxozoan, <strong><em>Henneguya caraubensis</em> n. sp.</strong>, is described from the gills of <em>Astyanax bimaculatus</em> (Linnaeus, 1758). Plasmodia were located within the gill lamellar epithelium, without connective tissue surrounding them. Mature myxospores were ellipsoidal in the frontal view, measuring 27.2 ± 2.6 μm in total length, 10.3 ± 0.7 μm in body length of spore, and 3.9 ± 0.2 μm in width. Two polar capsules elongated pyriform in shape, equal in size, measuring 3.4 ± 0.3 μm in length and 1.2 ± 0.1 μm in width. Polar tubules had 5 to 6 coils. Histopathological analysis showed large intralamellar polysporic plasmodia associated with displacement, deformation, and fusion of the nearest gill lamellae and with the adjacent lamellae being pushed laterally. Bayesian inference SSU rDNA-based phylogenetic analyses showed a strong tendency of <em>Henneguya</em>/<em>Myxobolus</em> species to form clusters mainly based on the order and/or family of the host, despite having different geographic origins. Phylogenetically, the novel species grouped within a clade containing <em>Henneguya</em>/<em>Myxobolus</em> spp. and appears in a well-supported subclade of <em>Henneguya</em> species parasites of <em>Astyanax</em> fishes. Our study reinforces highly endemic diversity still hidden that inhabits the Caatinga biome and points out the need to improve the strategies of protection and conservation of this threatened ecoregion with neglected biodiversity data.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103049"},"PeriodicalIF":1.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zinc pyrithione inhibits blood-stage parasites of Plasmodium falciparum and its combinatorial effect with dihydro-artemisinin and chloroquine in culture","authors":"Vinoth Rajendran ,&nbsp;Yuvan Raja Sivaraja","doi":"10.1016/j.parint.2025.103041","DOIUrl":"10.1016/j.parint.2025.103041","url":null,"abstract":"<div><div>The malarial parasite <em>Plasmodium falciparum</em> has evolved resistance to several antimalarial drugs, posing a significant challenge to the effective management and treatment of malaria in endemic areas. Drug repurposing has emerged as a potential alternative strategy for addressing this issue. This study aimed to identify an FDA-approved microbicidal agent, zinc pyrithione (ZPT), against mixed blood-stage parasites of <em>P. falciparum</em> chloroquine-sensitive (<em>Pf</em>3D7) and resistant strains (<em>Pf</em>INDO). Based on the time-inhibition kinetics assay, the parasite viability was significantly inhibited by ZPT treatment for 96 h (0.77 μM and 0.37 μM) and 72 h (0.63 μM and 0.61 μM), followed by 48 h (0.76 μM and 1.32 μM) and moderate inhibitory effects for 12 and 24 h in both <em>Pf</em>3D7 and <em>Pf</em>INDO culture. Stage-specific treatment revealed that trophozoites and schizonts exposed to ZPT were more susceptible than ring-stage parasites. Phenotypic assays revealed that trophozoites and schizonts failed to mature and exhibited aberrant morphologies such as condensed nuclei, as determined by Giemsa staining. Furthermore, ZPT in combination with dihydro-artemisinin and chloroquine demonstrated additive interactions in both <em>Pf</em>3D7 and <em>Pf</em>INDO parasites. At therapeutic dosages, ZPT failed to cause hemolysis in human erythrocytes. Overall, this study demonstrated a time-dependent effect of ZPT on the blood stages of human <em>P. falciparum</em> in culture, suggesting its utility in clinical settings.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103041"},"PeriodicalIF":1.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology, genetic characterization and molecular phylogeny of Xystrognathus priscus (Nematoda: Rhigonematomorpha)","authors":"Hong-Ru Xu ,&nbsp;Liang Li","doi":"10.1016/j.parint.2025.103040","DOIUrl":"10.1016/j.parint.2025.103040","url":null,"abstract":"<div><div>The infraorder Rhigonematomorpha is a unique group of zooparasitic nematodes commonly occurring in the hindgut of millipedes. Our present knowledge of the composition of the Rhigonematomorpha nematode fauna in China is far from complete. The current genetic data base for Rhigonematomorpha remains very limited, and the molecular phylogeny of Rhigonematomorpha is still in its beginning phase. In the present study, <em>Xystrognathus priscus</em> was redescribed using light microscopy and, for the first time, scanning electron microscopy based on the freshly collected specimens from <em>Litostrophus scaber</em> (Spirobolida: Pachybolidae) in China. SEM observations showed the detailed morphology of some structures for the first time, including cephalic structures bearing 1 pair of peg-like submedian cephalic papillae and 1 pair of amphidial apertures in ventral jaw, cuticular spines (microtrichs) varied from saw-tooth blade-like at anterior of body to tooth-like at posterior of body, excretory pore without cuticular spines surrounded, caudal papillae nipple-shaped, vulva without anterior vulval flap, egg with smooth surface and oval phasmid. The present study is only the second record of <em>X. priscus</em>, and also represents the first record of the species of the genus <em>Xystrognathus</em> and family Ichthyocephalidae in China. The partial 18S, 28S, ITS, <em>cox1</em> and <em>cox2</em> sequences of <em>X. priscus</em> were provided for the first time to enrich the genetic data of Rhigonematomorpha, and enabled the molecular identification of <em>Xystrognathus</em> nematodes. Additionally, phylogenetic results based on the partial 18S + 28S sequence data indicated that the families Ichthyocephalidae, Carnoyidae, Rhigonematidae and Xustromatidae in Rhigonematomorpha are all non-monophyletic, but strongly supported the monophyly of the genus <em>Xystrognathus</em>, and suggested a close affinity between <em>Xystrognathus</em> and the genus <em>Obainia</em> belonging to the Xustrostomatidae.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"107 ","pages":"Article 103040"},"PeriodicalIF":1.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological and molecular characterization of Myxobolus aculeatus n. sp. (Myxozoa: Myxosporea) from the ovary of Macrognathus aculeatus, Bloch, 1786 (Synbranchiformes: Mastacembelidae) in China","authors":"Liwen Xu ,&nbsp;Xiaojing Zhao ,&nbsp;Yu Huang ,&nbsp;Zhaozhe Xin ,&nbsp;Jinyong Zhang","doi":"10.1016/j.parint.2025.103039","DOIUrl":"10.1016/j.parint.2025.103039","url":null,"abstract":"<div><div><em>Macrognathus aculeatus</em> is a commercially significant cultured fish in China. However, prior to this study, there had been minimal attention directed towards its myxosporean infection. The present study has identified a previously unrecorded species of <em>Myxobolus</em> found in the ovary of <em>M. aculeatus</em>. The mature spores were elliptical in the frontal view, and fusiform in the sutural view, measuring 13.0 ± 0.2 (11.5–14) μm in length, 6.4 ± 0.3 (6.0–7.2) μm in width, and 5.3 ± 0.2 (4.9–5.6) μm in thickness. The two equal polar capsules were pyriform, with a length of 4.5 ± 0.2 (3.5–4.7) μm and a width of 2.4 ± 0.1 (2.3–2.6) μm, and contained 5–6 polar filament coils. A rigorous morphological comparison revealed that the current species exhibited notable distinctions from the previously documented congeners. Histopathological analysis indicated that the parasite resided between oocytes, yet no discernible host inflammatory response was observed. A comparison of the SSU rDNA gene sequences revealed that the present species exhibited the highest degree of similarity to <em>Myxobolus</em> parasites found in the gills of <em>Tachysurus fulvidraco</em>, with a sequence similarity of 86.54 %. Further phylogenetic analysis demonstrated that the current species exhibited a clustering pattern with several myxobolids infecting <em>Tachysurus</em> (Siluriformes), yet displayed a distinct positioning. The <em>Myxobolus</em> species in question represents a new scientific discovery and has been designated as <em>Myxobolus aculeatus</em> n. sp. on the basis of an integrated analysis of morphological, histopathological and molecular data.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"106 ","pages":"Article 103039"},"PeriodicalIF":1.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Blastocystis in humans and domestic animals: Risk factors assessment and potential zoonotic transmission in a periurban and rural region of Northeastern Argentina","authors":"Rumesilda Eliana Alegre ,&nbsp;Paula Josefina Vaschalde ,&nbsp;Francisca Milano ,&nbsp;Lucas Daniel Monje","doi":"10.1016/j.parint.2025.103035","DOIUrl":"10.1016/j.parint.2025.103035","url":null,"abstract":"<div><div><em>Blastocystis</em> is a protist that infects both human and animal hosts worldwide. This study aimed to investigate the presence of <em>Blastocystis</em> in humans and domestic animals living in a periurban (PZ) and rural zone (RZ) in Northeastern Argentina and to assess their relation to socio-environmental conditions and hygiene practices as risk factors for human infection. In addition, we identified <em>Blastocystis</em> subtypes to evaluate the risk of zoonotic transmission. A total of 563 fecal specimens were collected from 289 humans, principally children, and 274 animals. Samples were examined by coprological examination and further analysis by real-time PCR and sequencing were performed. A semi-structured questionnaire was applied to obtain socio-environmental and hygiene practices data. The results showed an overall prevalence of 41.6 % in children and 10.2 % in animals. Non-schooled children (OR = 0.54) and children from urban area (OR = 0.55) showed a lower risk of infection. Molecular analyses revealed five subtypes (ST1, ST2, ST3, ST5, and ST7) present in humans and four subtypes (ST1, ST5, ST7 and ST10) in animals. The overlap of STs between humans and domestic animals in the same household (STs 1, 5 and 7) suggests potential zoonotic transmission, underscoring the role of infected animals as a potential risk factor for human infections. Our results can inform local health authorities to promote policies aimed at reducing transmission, emphasizing the need for direct molecular-level assessments of other common environmental sources, such as water and soil, highlighting the importance of adopting a One Health approach to better understand <em>Blastocystis</em> circulation.</div></div>","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"106 ","pages":"Article 103035"},"PeriodicalIF":1.5,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143060016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic diversity and phylogeography of the global Theileria orientalis isolates inferred from MPSP gene sequences","authors":"El-Sayed El-Alfy ,&nbsp;Rana Elseadawy ,&nbsp;Somaya Saleh ,&nbsp;Bassem Elmishmishy ,&nbsp;Yara Al-Kappany ,&nbsp;Ibrahim Abbas","doi":"10.1016/j.parint.2025.103038","DOIUrl":"10.1016/j.parint.2025.103038","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Background/objective&lt;/h3&gt;&lt;div&gt;&lt;em&gt;Theileria orientalis&lt;/em&gt; is a non-transforming &lt;em&gt;Theileria&lt;/em&gt; species infecting cattle and water buffaloes. Several outbreaks of oriental theileriosis accompanied by considerable economic loss were documented in Asia, Australia, and New Zealand. The major piroplasm surface protein (MPSP) gene has frequently been used to molecularly characterize &lt;em&gt;T. orientalis&lt;/em&gt; isolates worldwide. Various MPSP genotypes were detected with significant virulence variations. The present study provides the first in silico analysis for all globally published &lt;em&gt;T. orientalis&lt;/em&gt; MPSP isolates to evaluate their phylogeny, diversity, and population structure.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Methods&lt;/h3&gt;&lt;div&gt;All studies that tested &lt;em&gt;T. orientalis&lt;/em&gt; isolates using PCR-MPSP protocols were systematically collected from various databases. &lt;em&gt;Theileria orientalis&lt;/em&gt; MPSP-sequenced isolates on the GenBank were collected and the sequences were tested for their phylogenetic relatedness, genetic diversity, recombination, natural selection, and population structure using various software.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;The collected &lt;em&gt;T. orientalis&lt;/em&gt;-MPSP isolates (&lt;em&gt;n&lt;/em&gt; = 795) were clustered into 12 genotypes, including types 1 (Chitose), 2 (Ikeda), 3 (Buffeli), 4, 5, 7, 8, and N1-N5. The previously identified type 6 belonged to a separate species (&lt;em&gt;Theileria sinensis&lt;/em&gt;). The previously identified type 9 was transferred to type 4. Two unidentified isolates from water buffaloes in India were clustered into a new suggested genotype “type N5”. Of the 12 genotypes, Ikeda (type 2) is the most virulent in cattle. However, a few clinical cases have also been linked to types 1 (Chitose) and 7. In water buffaloes, &lt;em&gt;T. orientalis&lt;/em&gt; outbreaks have been linked to genotypes N2 and N5. Geographic mapping of various genotypes revealed the dispersal of types 1 and 3 worldwide. Overall, the 795 isolates comprised 532 haplotypes and displayed very high nucleotide (π = 0.14) and haplotype (Hd = 0.995) diversities. As a result, a very low sequence conservation value (C = 0.207) was determined. The twelve genotypes displayed comparable haplotype diversities accompanied by statistically significant negative Tajima's D and Fu's Fs values suggesting population expansion. A high value for the minimum number of recombination events (Rm = 65) was estimated for the 795 isolates, and this value varied from 0 to 23 at the genotype level. Most types also displayed significant positive selection (dn/ds ratio &gt; 1). This suggests that both recombination and positive selection occur in &lt;em&gt;T. orientalis&lt;/em&gt; MPSP gene, which could explain the very high genetic diversity among various &lt;em&gt;T. orientalis&lt;/em&gt; types. Different patterns were detected for the gene flow among &lt;em&gt;T. orientalis&lt;/em&gt; populations from various hosts and geographies; however, there is evidence for the genetic relatedness between populations from neighbouring c","PeriodicalId":19983,"journal":{"name":"Parasitology International","volume":"106 ","pages":"Article 103038"},"PeriodicalIF":1.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143041028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}