International Journal for Parasitology: Drugs and Drug Resistance最新文献

{"title":"Faecal egg count reduction test, deep amplicon sequencing of isotype-1 β-tubulin gene and in ovo larval development assay reveal susceptibility to benzimidazoles of porcine nematodes Oesophagostomum spp. and Ascaris suum in outdoor-reared pigs in Germany","authors":"Hannah RM. Fischer ,&nbsp;Jürgen Krücken ,&nbsp;Stefan Fiedler ,&nbsp;Stig M. Thamsborg ,&nbsp;Hendrik Nienhoff ,&nbsp;Stephan Steuber ,&nbsp;Ricarda Daher ,&nbsp;Georg von Samson-Himmelstjerna","doi":"10.1016/j.ijpddr.2025.100612","DOIUrl":"10.1016/j.ijpddr.2025.100612","url":null,"abstract":"<div><div><em>Oesophagostomum</em> spp. and <em>Ascaris suum</em> represent the most common porcine nematodes and anthelmintic resistance (AR) to various anthelmintics has been reported for <em>Oesophagostomum</em>. However, the current AR status for worm populations on German farms and practical methods facilitating reliable AR detection are missing. Herein, the efficacy of benzimidazoles (BZ) (fenbendazole, 5 mg/kg body weight, single dose) was analysed on 13 farms with outdoor access. The Faecal Egg Count Reduction Test (FECRT) estimates for strongyles on the farms (range 99.8–100 %) exceeded the target efficacy (99 %) of the new W.A.A.V.P. guideline for <em>Oesophagostomum dentatum.</em> Deep amplicon sequencing was used for the first time for porcine nematodes and revealed no polymorphisms associated with BZ-resistance in codons 134, 167, 198 and 200 of the isotype-1 β-tubulin gene. Nemabiome analysis using ITS-2 deep amplicon sequencing, based on two pre- and post-treatment samples, showed a significant increase (p &lt; 0.001) of <em>Oesophagostomum quadrispinulatum</em> after BZ treatment. For <em>A. suum,</em> the interpretation of FECRT estimates can be hindered due to coprophagy-associated false-positive egg counts in pigs. Therefore, two FECRT analysis for <em>A. suum</em> were pursued, the first analyses included all EPG data, the second considered EPGs &lt;200 pre- and post-treatment as negative. An <em>in ovo</em> larval development assay (LDA) was developed for the <em>in vitro</em> analysis of BZ-susceptibility in <em>A. suum</em>. Computed EC₅₀ values ranged from 1.50 to 3.36 μM thiabendazole (mean 2.24 μM). An EC₅₀ of 3.90 μM thiabendazole (mean EC₅₀ + 3 × SD) as provisional cut-off for detection of resistant populations is suggested. In conclusion, no AR was detected in <em>Oesophagostomum</em> using the FECRT and β-tubulin deep amplicon sequencing. For <em>A. suum</em> the FECRT results were ambiguous<em>,</em> in some cases even when excluding the low egg counts from calculations. With the <em>in ovo</em> LDA all investigated <em>A. suum</em> populations were identified as susceptible to BZ.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100612"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932528","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":"CRISPR-Cas13b mediated gene knockdowns in Leishmania infantum","authors":"Marine Queffeulou,&nbsp;Raouia Fakhfakh ,&nbsp;Fereshteh Fani ,&nbsp;Alex Dos Santos,&nbsp;Gabriel Reis Ferreira,&nbsp;Sophia Bigot,&nbsp;Chantal Godin,&nbsp;Philippe Leprohon,&nbsp;Barbara Papadopoulou,&nbsp;Marc Ouellette","doi":"10.1016/j.ijpddr.2025.100629","DOIUrl":"10.1016/j.ijpddr.2025.100629","url":null,"abstract":"<div><div>Chemotherapy is an effective means to control infections caused by the protozoan parasite <em>Leishmania</em>. However, available treatments are limited, expensive, and associated with considerable toxicity. Genomic strategies have contributed to a better understanding of <em>Leishmania</em>'s response to drugs and in the characterization of drug targets. Nonetheless, there is no knockdown system operational for <em>Leishmania</em>. In this study, we show that the CRISPR-Cas13 system can be an effective strategy to knockdown expression levels of both exogenous and endogenous transcripts. We succeeded in effectively knocking down the expression of the firefly luciferase gene integrated in the genome of <em>L. infantum</em>. This Cas13-mediated decrease in mRNA was paralleled with a significant reduction in both the luciferase protein level and its activity. Furthermore, we tested the effectiveness of the Cas13 system to target the endogenous miltefosine transporter (<em>MT</em>) and the aquaglyceroporin 1 (<em>AQP1</em>) genes. Knockdown was effective and parasites with less <em>MT</em> or <em>AQP1</em> mRNA levels exhibited reduced susceptibility to miltefosine or antimonials, respectively. While further optimization is warranted, this knockdown system has the potential to facilitate numerous studies related to various aspects of <em>Leishmania</em> biology.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100629"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145714255","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":"Evaluating the efficacy of different praziquantel treatment regimens using egg and circulating anodic antigen (CAA) detection methods in a Schistosoma mansoni endemic area in northeastern Brazil","authors":"Rosangela Lima de Freitas Galvão ,&nbsp;Pytsje T. Hoekstra ,&nbsp;Paul L.A.M. Corstjens ,&nbsp;Marta Cristhiany Cunha Pinheiro ,&nbsp;Angela Maria da Silva ,&nbsp;Luciene Barbosa ,&nbsp;Sidney Lourdes César Souza Sá ,&nbsp;Govert J. van Dam ,&nbsp;Fernando Schemelzer de Moraes Bezerra","doi":"10.1016/j.ijpddr.2025.100628","DOIUrl":"10.1016/j.ijpddr.2025.100628","url":null,"abstract":"<div><div>This study evaluated the efficacy of different treatment regimens with PZQ against <em>S</em><em>chistosoma mansoni</em> infection. Residents of the Patioba and Colônia Miranda villages (Sergipe, Brazil) with a confirmed diagnosis of <em>S. mansoni</em> infection were randomized into one of the study groups and treated with a standard dose of PZQ (Group 1); with two doses spaced 24 hours apart (Group 2); or with two doses spaced 30 days apart (Group 3). Efficacy was assessed 30 days after the final treatment, based on the detection of eggs in feces using the Kato-Katz (KK) method and on the detection of CAA in urine using the Up-Converting Particle Lateral Flow (UCP-LF) assay. A total of 88 participants, who tested positive for infection by KK and UCP-LF CAA at baseline, were included in the statistical analysis. Cure rates (CRs) reached 100 % in all three study groups, according to KK. The UCP-LF CAA revealed that not all participants were cured, with the highest cure rate observed in Group 2 (69.6 %%), followed by Group 3 (57.7 %) and Group 1 (43.8 %). An Intensity Reduction Rate (IRR) of 100 % and &gt;97 % was observed in all groups, based on KK and UCP-LF CAA, respectively. Reduction in <em>S. mansoni</em> burden was observed over time, with the IRR in all groups exceeding the efficacy threshold established by the WHO (&gt;90 %). Cure rates varied according to the diagnostic method used, being overestimated when based on egg quantification, highlighting the importance of using more sensitive tools for the detection of active infections and monitoring the efficacy of PZQ.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100628"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145668128","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 the inhibitory effects of emodin on Neospora caninum invasion and proliferation in vitro","authors":"Feixue Liu ,&nbsp;Jianhua Li ,&nbsp;Xin Li,&nbsp;Xu Zhang,&nbsp;Liuzhenxiu Yan,&nbsp;Lanbi Gao,&nbsp;Zhenzhen Liu,&nbsp;Pengtao Gong,&nbsp;Nan Zhang,&nbsp;Xichen Zhang,&nbsp;Xiaocen Wang","doi":"10.1016/j.ijpddr.2025.100624","DOIUrl":"10.1016/j.ijpddr.2025.100624","url":null,"abstract":"<div><div>The impact of neosporosis on the livestock industry has worsening each year. Globally, annual losses were estimated to exceed $2.4 billion, with abortion rates reaching up to 47 % in affected herds. But no effective vaccines or drugs are currently available for prevention and treatment. This study aimed to investigate the inhibitory effects of emodin on <em>Neospora caninum</em> (<em>N</em>. <em>caninum</em>) infection and its potential mechanisms. The appropriates safe concentration of emodin was determined by the Cell Counting Kit-8 (CCK-8) assay. The anti-<em>N. caninum</em> effects of emodin in Vero cells, MDBK cells, macrophages, as well as the combined effects of emodin and niclosamide in Vero cells, were further verified using qPCR or Giemsa staining. Subsequently, the effects of direct incubation of tachyzoites with emodin on <em>N. caninum</em> invasion and proliferation were also examined. The activation of necroptosis by emodin was evaluated by measuring Lactate Dehydrogenase (LDH) levels in the supernatant and assessing cellular pMLKL levels. The CCK-8 results indicated that emodin exhibited low toxicity to Vero cells, MDBK cells, and macrophages. The qPCR results showed that emodin reduced the number of <em>N. caninum</em> in Vero cells, MDBK cells, and macrophages. Giemsa results showed that the number of tachyzoites within the parasitophorous vacuole was decreased accordingly. Notably, emodin directly affected tachyzoites, reducing its invasion capability by 55 %–63 % and its proliferation capacity by 62 %–88 %. Additionally, the combination of emodin with niclosamide significantly enhanced its antiparasitic effects compared with emodin alone. Western blot analysis showed that emodin significantly increased pMLKL levels and enhanced LDH release, assisting <em>N. caninum</em> in activating necroptosis. However, the inhibitory effects of emodin on <em>N. caninum</em> invasion and proliferation were not significantly altered in <em>Mlkl</em>^{<em>−/−</em>} macrophages. In conclusion, emodin inhibited <em>N. caninum</em> infection may through a necroptosis-independent mechanism by directly targeting the parasite, highlighting its potential as a therapeutic candidate for neosporosis.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100624"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145444678","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":"Dual-targeting proteasome inhibitor ONX-0914 demonstrates potent antiplasmodial activity for malaria treatment","authors":"Nguyen Van Truong ,&nbsp;Tuyet-Kha Nguyen ,&nbsp;Nguyen Sy Thau ,&nbsp;Thi-Thanh Hang Chu ,&nbsp;Bazgha Sanaullah ,&nbsp;Ch Venkataramaiah ,&nbsp;Jin-Hee Han ,&nbsp;Sung-Hun Na ,&nbsp;Won-Sun Park ,&nbsp;Wan-Joo Chun ,&nbsp;Joo Hwan No ,&nbsp;Eun-Taek Han","doi":"10.1016/j.ijpddr.2025.100613","DOIUrl":"10.1016/j.ijpddr.2025.100613","url":null,"abstract":"<div><div>There is an urgent need to discover novel antimalarial drugs that are safe and provide effective cures with broad therapeutic potential, novel mechanisms of action, and suitable pharmacokinetic profiles. We studied ONX-0914, which targets the proteolytic system of eukaryotic cells and has been effective against cancer and immune disorders. The antiplasmodial activity and safety of ONX-0914 were investigated both <em>in vitro</em> and <em>in vivo</em>, along with its mechanism of action and potential bioavailability. Notably, ONX-0914 strongly inhibited the proliferation of various <em>Plasmodium falciparum</em> strains, including chloroquine (CQ)- and artesunate (ART)-sensitive and -resistant strains, with a low nanomolar IC₅₀ (&lt;50nM). It also exhibited potent synergistic activity with ART, blocking the proliferation of ART- and CQ-resistant strains, while showing low toxicity to human cells (CC₅₀ &gt; 100 μM). The potent antiplasmodial activity of ONX-0914 is attributed to the dual inhibition of haemoglobin metabolism and the ubiquitin‒proteasome system. <em>In vivo</em> results revealed that ONX-0914 suppressed <em>P. berghei</em> ANKA parasites by &gt; 95 % after 4 days of treatment and increased survival rate and mean survival time following a single dose administered via various routes (effect dose ED₅₀ of 7.62 mg/kg per oral [PO] and 6.52 mg/kg intraperitoneal [IP], and intravenous [IV]). ONX-0914 treatment resulted in a low recrudescence rate after one month (&lt;2 %), reduced organ lesions (brain, heart, lung, liver, spleen, and kidney) compared to untreated controls, and favourable pharmacokinetic parameters (AUC &gt;20,960 h∗μg/ml, T_1/2 = 7.9 h [IV], 0.7 h [PO], C _max = 10708.2 μg/ml [PO], bioavailability = 23.83 %), supporting its antimalarial efficacy. Owing to its low toxicity, robust antiplasmodial activity through a combination mechanism, and supportive pharmacokinetic properties, ONX-0914 is a promising antimalarial agent.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100613"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118501","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 intron variant is associated with emerging pfdhps mutant haplotypes in West and Central African Plasmodium falciparum","authors":"Emma Filtenborg Hocke ,&nbsp;Helle Hansson ,&nbsp;Ana Chopo-Pizarro ,&nbsp;Adebanjo Jonathan Adegbola ,&nbsp;Oluseye Bolaji ,&nbsp;Peter Thelma Ngwa Niba ,&nbsp;Innocent Mbulli Ali ,&nbsp;Akindeh Nji ,&nbsp;Wilfred Mbacham ,&nbsp;Vito Baraka ,&nbsp;Neema B. Kulaya ,&nbsp;Gauthier Mesia Kahunu ,&nbsp;Hypolite Muhindo Mavoko ,&nbsp;Papy Mandoko Nkoli ,&nbsp;Eric Mukomena Sompwe ,&nbsp;Destin Mbongi ,&nbsp;Patrick Mitashi ,&nbsp;Valérie A. Bédia ,&nbsp;Paterne A. Gnagne ,&nbsp;Abibatou Konaté ,&nbsp;Cally Roper","doi":"10.1016/j.ijpddr.2025.100611","DOIUrl":"10.1016/j.ijpddr.2025.100611","url":null,"abstract":"<div><div>Sulfadoxine-pyrimethamine plays a key role in <em>Plasmodium falciparum</em> chemoprevention across Africa, yet the protective efficacy of SP is undermined by mutations conferring resistance in the genes encoding dihydrofolate reductase (<em>pfdhfr</em>) and dihydropteroate synthase (<em>pfdhps</em>). The emergence and spread of the <em>pfdhps</em> 431V mutation suggests that this may confer resistance and be selected by drug use. Here, we report a non-coding mutation a548383t, which expands a di-nucleotide repeat in the first intron of <em>pfpppk-dhps</em>. The first intron and second exon of the <em>pfdhps</em> gene were analysed by target amplicon sequencing of 929 <em>P. falciparum</em>-positive blood samples from Nigeria, Cameroon, Tanzania, The Democratic Republic of Congo, and Côte d’Ivoire. The intron mutation was found in Nigeria, Côte d’Ivoire, and Cameroon in association with the 431V mutation. In particular, the intron mutation was most highly associated with the <strong>VAG</strong>K<strong>GS</strong> haplotype (OR = 211.7, P &lt; 0.001), followed by the <strong>VAG</strong>KA<strong>S</strong> (OR = 39.2, P &lt; 0.001), and <strong>VAG</strong>KAA (OR = 33.6, P &lt; 0.001) haplotypes. Additionally, a reduced di-nucleotide repeat diversity was observed in 431V-positive variants. The intron variant is significantly associated with the 431V mutation which is consistent with previous reports of selective sweeps around <strong>VAG</strong>K<strong>GS.</strong> The association of the 548383t mutation with both <strong>VAG</strong>K<strong>GS, VAG</strong>KA<strong>S</strong> and <strong>VAG</strong>KAA might indicate these lineages either have a common ancestor or that the intron variant 548383t has a functional association with 431V. More research is needed to determine if the association is simply genetic hitchhiking, or if the intron variant confers a phenotypic advantage.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100611"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908311","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":"Challenges in applying W.A.A.V.P. criteria to diagnosing triclabendazole resistance in Fasciola hepatica, an example from the Southern Tablelands of New South Wales, Australia","authors":"Chelsie Uthayakumar ,&nbsp;Hayley Martinez DeCristi ,&nbsp;Emily Kate Francis ,&nbsp;Roger Alan Willoughby ,&nbsp;Shannon Taylor ,&nbsp;Nichola Eliza Davies Calvani","doi":"10.1016/j.ijpddr.2025.100618","DOIUrl":"10.1016/j.ijpddr.2025.100618","url":null,"abstract":"<div><div><em>Fasciola hepatica</em> (liver fluke) is a zoonotic parasite of global concern. In Australia, it is the 13th most important cause of economic loss in the sheep meat industry alone. Resistance to the frontline drug, triclabendazole (TCBZ), was first recorded in Australia in 1995 and has since emerged globally. In 2023, producers from the New South Wales (NSW) Southern Tablelands raised concerns over a reported 230% increase in liver fluke, which they suspected was due to drug resistance. To confirm or deny these suspicions, we co-designed a diagnostic field investigation aligned with guidelines from the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) to evaluate the prevalence and susceptibility of <em>F. hepatica</em> on naturally infected sheep, cattle, and goat properties. Nine mobs (seven sheep, one goat, one cattle) across eight farms were divided into three treatment groups (15 animals/group) and treated with either TCBZ, closantel/abamectin (CLOS/AVM, positive control – sheep), albendazole (ABZ, positive control – goats), or water (H₂O; negative control). Prevalence was determined by sedimentation and faecal egg count (FEC), alongside a commercial coproantigen ELISA (cELISA) and in-house qPCR. Drug efficacy was assessed using faecal egg count reduction tests (FECRT) and coproantigen reduction tests (CRT). Four of the eight farms had a within-herd true prevalence &gt;25%. TCBZ resistance was confirmed on one sheep property (86–89% efficacy). The goat property demonstrated susceptibility to TCBZ (97–98% efficacy), but reduced efficacy of ABZ (79%), representing the first potential report of ABZ resistance in <em>F. hepatica</em> infecting goats. Nemabiome sequencing of co-infecting gastrointestinal nematodes confirmed widespread benzimidazole resistance, underscoring the broader challenges faced by producers. Other potential causes of drug failure included climate variability, pseudo-parasites, and low cELISA diagnostic sensitivity. These results highlight the complexity of diagnosing and managing drug resistance in naturally infected populations and reinforce the need for <em>Fasciola</em>-specific W.A.A.V.P. guidelines.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100618"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145250989","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":"Surveillance of single nucleotide polymorphisms correlated to macrocyclic lactone resistance in Dirofilaria immitis from client-owned dogs across the United States.","authors":"Emily Curry, David Tack, Jessica Rodriguez, Danielle Brehm-Lowe, John Letherer, Megan Lineberry, Roger Prichard, Tobias Clark","doi":"10.1016/j.ijpddr.2025.100604","DOIUrl":"10.1016/j.ijpddr.2025.100604","url":null,"abstract":"<p><p>Dirofilaria immitis is a parasitic filarial nematode and the causative agent of heartworm disease in canids and other species. Heartworm disease is predominantly managed via macrocyclic lactone (ML) - based chemoprophylactics. Through opportunistic sampling, genotypically and phenotypically confirmed ML-resistant D. immitis isolates have been isolated in the Lower Mississippi River Valley region (LMRV); however, the pervasiveness of resistant isolates in the USA has not been evaluated. This study aimed to evaluate the geographic distribution and prevalence of genotypically ML-resistant heartworms in client-owned dogs across the USA over a 3-year period. Owner consent was obtained to collect microfilaremic blood samples from heartworm-positive dogs from participating clinics. Veterinarians completed a questionnaire on the known history of each dog, including treatment and travel history. A total of 310 microfilaremic blood samples were collected from 45 geographically diverse veterinary clinics located in 22 states. Microfilariae were filtered from blood, DNA extracted utilizing the QIAGEN QIAamp DNA Micro Kit and samples sequenced by the Génome Québec Innovation Centre to determine allele frequencies at nine SNP sites previously correlated with ML resistance. The highly predictive 2-SNP model was used to identify genotypically susceptible, mixed, and resistant populations. Computational analysis indicated 111 (35.8 %) were genotypically susceptible, 96 (31.0 %) were genotypically resistant, and 103 (33.2 %) were genotypically mixed. The genotypically mixed and ML-resistant infections were located within and outside of the endemic LMRV, as far north as Michigan, which indicates canine populations outside of the LMRV are at increased risk for transmission of potentially ML-resistant heartworm infections than previously hypothesized. Veterinary practitioners across the USA need to be aware of the potential risks of ML resistance heartworm infections and ensure patient compliance with recommended prevention protocols.</p>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"100604"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12355919/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144804035","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":"Similar patterns of benzimidazole resistance alleles in ovine gastrointestinal nematodes from Western Canada and Eastern United States supports their shared origins and subsequent spread","authors":"Camila Queiroz ,&nbsp;Michel Levy ,&nbsp;Russell Avramenko ,&nbsp;Rebecca Chen ,&nbsp;Michaela Seal ,&nbsp;Elizabeth Redman ,&nbsp;Anne Zajac ,&nbsp;John Stuart Gilleard","doi":"10.1016/j.ijpddr.2025.100620","DOIUrl":"10.1016/j.ijpddr.2025.100620","url":null,"abstract":"<div><div>Livestock movement facilitates translocation of anthelmintic resistant parasites, but the extent to which resistance emergence depends on animal movement is still poorly understood. Benzimidazole resistance is widespread in ovine trichostrongylid nematodes, and our understanding of its molecular basis now allows for molecular epidemiology investigations. This study applies deep amplicon sequencing of the isotype-1 β-tubulin locus to compare the prevalence and frequency of benzimidazole resistance Single Nucleotide Polymorphisms (SNPs), and their alleles, for trichostrongylid populations from 102 Western Canadian and 28 Eastern USA sheep flocks. For <em>H. contortus</em>, benzimidazole resistance SNPs were at fixation tin almost all flocks from both regions; that is, present at, or close to, 100 % frequency. For <em>T. circumcincta</em> and <em>T. colubriformis</em>, although at fixation in most Eastern USA flocks, resistance SNPs they were at a much lower prevalence in Western Canada, consistent with the lower anthelmintic use and selection pressure. The benzimidazole resistance SNP profiles were identical across these regions: F200Y (TTC &gt; TAC) predominated for all three species in both regions, but there were differences between the species at codons 167 and 198. For <em>H. contortus</em>, F167Y (TTC &gt; TAC) was at moderate prevalence but no codon 198 resistance SNPs occurred in either region. For <em>T. circumcincta</em>, E198A (GAA &gt; GCA) was at low prevalence and for <em>T. colubriformis</em>, F200Y (TTC &gt; TAC) was the only resistance SNP detected in both regions. Analysis of diversity and distribution of Amplicon Sequence Variants (ASVs) carrying resistance SNPs revealed that, in all three species, the same major resistance alleles were present in both regions at very similar relative frequencies. These results are consistent with a model of benzimidazole resistant ovine gastrointestinal nematodes (GIN) spreading across North America from common origins facilitated by animal movement. This model emphasizes the importance of biosecurity in limiting the emergence and spread of anthelmintic resistance in ruminant GIN. Keywords: molecular epidemiology, deep amplicon sequencing, anthelmintic resistance, nemabiome, benzimidazoles.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100620"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266501","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":"Validation of solvent proteome profiling for antimalarial drug target deconvolution","authors":"Yijia Ji ,&nbsp;Joshua P. Morrow ,&nbsp;Christopher A. MacRaild ,&nbsp;Haijian Zhang ,&nbsp;Carlo Giannangelo ,&nbsp;Ralf B. Schittenhelm ,&nbsp;Darren J. Creek ,&nbsp;Ghizal Siddiqui","doi":"10.1016/j.ijpddr.2025.100626","DOIUrl":"10.1016/j.ijpddr.2025.100626","url":null,"abstract":"<div><div>Malaria remains a global health threat, with rising drug resistance accelerating the urgent need for new therapeutics. Target elucidation is a critical step in antimalarial drug discovery, enabling a deeper understanding of the molecular mechanisms of action of both existing and novel compounds. This study validates solvent-induced proteome profiling (SPP) as a proteomics-based approach for identifying drug-protein interactions in <em>Plasmodium falciparum</em>. SPP detects shifts in protein stability induced by ligand binding, allowing the identification of drug target/s without the need for compound modifications. Here, we successfully generated solvent denaturation curves for the <em>P. falciparum</em> proteome, and demonstrated the utility of SPP with five antimalarial compounds: pyrimethamine, atovaquone, cipargamin, MMV1557817 and OSM-S-106. In addition to measuring each compound's impact across the full denaturation curve, investigating protein levels at individual solvent percentages preserved specific stability changes that would otherwise be masked in pooled analyses performed by integral SPP. This strategy was critical for the identification of the cipargamin target, non-SERCA-type Ca²⁺-transporting P-ATPase (<em>Pf</em>ATP4). Notably, we propose live-cell treatment SPP as a novel approach, demonstrating its ability to identify the validated target of pyrimethamine, bifunctional dihydrofolate reductase-thymidylate synthase (<em>Pf</em>DHFR), with high specificity. We also introduced the novel one-pot mixed-drug SPP, which enables the evaluation of multiple drugs within a single lysate and experimental setup. This alternative method simplifies the experimental workflow and includes positive controls to affirm the performance of the experiment. Overall, this study demonstrates that SPP can be successfully applied in both lysate and live-cell treatment conditions to elucidate drug targets in <em>P. falciparum,</em> as well as providing additional information regarding the mechanisms of drug action, offering insights for the optimisation of existing antimalarials and the development of novel therapies.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"29 ","pages":"Article 100626"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614201","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}