International journal for parasitology最新文献

{"title":"Immunity against reinfection in pigs following Taenia solium infection and a quantitative dose-response model.","authors":"Eloy Gonzales-Gustavson, Francesco Pizzitutti, Gabrielle Bonnet, Claudio Muro, Ricardo Gamboa, Javier A Bustos, Sarah Gabriël, William K Pan, Héctor H Garcia, Seth O'Neal","doi":"10.1016/j.ijpara.2025.08.010","DOIUrl":"10.1016/j.ijpara.2025.08.010","url":null,"abstract":"<p><p>Taenia solium is a zoonotic parasite causing significant health and economic burdens, with complex transmission dynamics that demand improved control strategies. This study examines how infection and reinfection affect cyst development in pigs and how acquired immunity constrains parasite burden. A total of 116 pigs were purchased from commercial farms in northern Peru and housed under controlled conditions. Of these, 110 pigs were allocated to 18 experimental groups to evaluate the impact of single and repeated infections with varying doses of T. solium eggs and to model the number of live cysts produced based on dose and age at infection. Gravid proglottids collected from human cases were used to prepare viable egg pools. Infections were administered orally via esophageal catheterization, and pigs were necropsied 10 weeks after the final infection to quantify cyst burden. A negative binomial regression model assessed the influence of infection dose, prior infection, age, and other factors. No significant differences in cyst counts were found between singly infected and reinfected pigs, regardless of initial or reinfection doses, highlighting that infection induces strong acquired immunity that prevents subsequent infections. A dose-response analysis indicated that cyst burden follows a power relationship with egg dose. Integrating data from both single and reinfected pigs into a unified model improved prediction precision. Furthermore, incorporating age at infection allowed us to model the combined effects of acquired and innate immunity, reflecting changes in susceptibility over time. These findings demonstrate that a single exposure to T. solium eggs can generate robust protective immunity in pigs. The resulting quantitative model, predicting viable cyst counts based on dose and age, offers valuable insights for integrating immunity dynamics into transmission models, supporting the development of more effective strategies for controlling T. solium.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953021","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":"Wildlife fleas and ticks in Wisconsin, USA: unrecognized vectors of bacterial pathogens.","authors":"Charlotte O Moore, Caroline V Andrews, Erin M Lemley, Michelli Inacio Gonçalves Funnicelli, Marcos Rogério André, Edward B Breitschwerdt, Erin Lashnits","doi":"10.1016/j.ijpara.2025.08.004","DOIUrl":"https://doi.org/10.1016/j.ijpara.2025.08.004","url":null,"abstract":"<p><p>Small wildlife species host flea and tick species that can also infest or transmit pathogens to domestic animals and humans, including Anaplasma, Babesia, Bartonella, Borrelia, Ehrlichia, and Rickettsia species. Despite their zoonotic potential, little is known regarding the prevalence, diversity, and epidemiology of these pathogens. Therefore, we aimed to survey the ectoparasites found on Eastern Cottontail Rabbits (rabbits), Eastern Grey Squirrels (squirrels), and Virginia Opossums (opossums) in south-central Wisconsin, and describe the prevalence of select pathogens. Ectoparasites were opportunistically collected from small mammals, then identified to the species level, pooled, washed, and DNA extracted for quantitative PCR (qPCR) to detect Anaplasmataceae, Apicomplexa, Bartonella, hemotropic Mycoplasma, and Rickettsia. To analyze the genomic diversity of uncharacterized Bartonella, three flea pools were subject to metagenomic sequencing. Cediopsylla simplex and Haemaphysalis leporispalustris were the most common ectoparasites on rabbits, while Orchopeas howardi was most common on squirrels and opossums. Bartonella species were detected in C. simplex pools (n = 52), most commonly two distinct Bartonella alsatica-like bacteria (38 %; 20/52). Bartonella durdenii, definitively identified by metagenomic sequencing, was detected in 42 % (13/31) of O. howardi pools from squirrels. From metagenomic sequencing, B. alsatica-like species displayed a 4.8 % dissimilarity rate while B. durdenii displayed a 0.4 % dissimilarity rate. Sequencing of one B. alsatica-like flea pool also identified phage-associated genes not found in the B. alsatica genome. Rickettsia felis (n = 1) and opossum-associated hemotropic Mycoplasma sp. (n = 2) were detected in O. howardi from opossums. Rickettsia bellii and Anaplasma sp. were detected in Haemaphysalis leporispalustris from rabbits. These findings reinforce the value of metagenomic sequencing, facilitating the correct identification of B. durdenii and identifying genes not found in the type strain, specifically phage related genes. Due to the known zoonotic potential of B. alsatica, further examination of B. alsatica-like and B. durdenii pathogenicity is warranted.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953024","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":"Indigenous Plasmodium vivax upsurge in the Eastern Mediterranean, Western Pacific, and South East Asia regions - beyond the constant culpability of climate change, COVID-19, and armed conflicts.","authors":"Loick P Kojom Foko, Amit Sharma","doi":"10.1016/j.ijpara.2025.08.009","DOIUrl":"10.1016/j.ijpara.2025.08.009","url":null,"abstract":"<p><p>Controlling Plasmodium vivax presents greater challenges compared to Plasmodium falciparum. Here, we analyzed epidemiological data on indigenous P. vivax cases from the Eastern Mediterranean, Southeast Asia, and Western Pacific regions in recent years. Significant upsurges are observed in more than half of the countries within these regions. In Papua New Guinea and Yemen, the increase has been consistent since 2015, while others, including Indonesia and Pakistan, have experienced sharp rises between 2020 and 2023 (e.g., +100 % and +83.4 %). Notably, in countries like Thailand, initially targeted by the WHO E-2025 elimination initiative, achieving elimination by 2025 appears unlikely. Factors like the COVID-19 pandemic, armed conflicts, and, more recently, climate change, do not fully resolve the reasons for resurgence in countries like Papua New Guinea, where additional issues such as chloroquine resistance must also be addressed. A compartmentalized approach is essential to tackle the P. vivax resurgence and achieve meaningful progress effectively.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953029","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":"Reclaimed wetlands support rich trematode and host diversity: findings from a four-year survey.","authors":"Brooke A McPhail, Sara Tomusiak, Hannah Veinot, Neill Dodds, Patrick C Hanington","doi":"10.1016/j.ijpara.2025.08.006","DOIUrl":"https://doi.org/10.1016/j.ijpara.2025.08.006","url":null,"abstract":"<p><p>Snail hosts play a central role in structuring trematode communities. To test how snail hosts shape parasite diversity in central Alberta, we built upon a previous snail-trematode survey conducted at six lakes in central Alberta from 2013 to 2015 that uncovered 79 trematode species. However, analyses suggested that additional species remained to be uncovered. To build on this baseline, we conducted further snail-trematode collections from 2019 to 2022 at eight reclaimed wetland sites in various stages of reclamation, along with one established lake in Alberta. Across the nine sites, we collected 22,397 snails, of which 1981 were infected with digenetic trematodes. We also documented broader biodiversity at these sites using traditional survey techniques. Through DNA barcoding, we identified 74 trematode species infecting five snail species. Among these were 23 trematode species not previously reported in central Alberta and nine provisionally-named lineages with no matches to species in publicly available databases. In addition, we observed several previously unreported snail-trematode interactions. While trematode richness did not vary significantly with the wetland reclamation stage, host identity did influence richness: Physa gyrina hosted significantly more trematode species than Planorbella trivolvis. When combined with data from the earlier survey, sample completeness analyses indicate that we captured 100 % of the dominant species and 99 % of the typical species, but only 63 % of the overall species diversity in central Alberta. These findings underscore that trematode diversity in central Alberta remains incompletely characterized and highlight the continued value of long-term and host-inclusive sampling efforts.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The key glycolytic enzyme phosphofructokinase is involved in Eimeria tenella resistance to maduramycin.","authors":"Huanzhi Zhao, Qiping Zhao, Shunhai Zhu, Liushu Jia, Yu Yu, Jinwen Wang, Sishi Zhang, Qian Feng, Jia Yang, Bing Huang, Hui Dong, Hongyu Han","doi":"10.1016/j.ijpara.2025.08.008","DOIUrl":"https://doi.org/10.1016/j.ijpara.2025.08.008","url":null,"abstract":"<p><p>The protozoan parasite Eimeria tenella causes coccidiosis in poultry, which results in substantial economic losses to the global poultry industry. Understanding the molecular mechanisms of drug resistance in E. tenella is essential for developing effective control strategies. The goal of this study was to investigate the role of E. tenella phosphofructokinase (EtPFK1) in mediating resistance to maduramycin, a widely used anticoccidial drug. Characterization of EtPFK1 expression across developmental stages and under drug treatment revealed elevated mRNA and protein levels in sporulated oocysts and maduramycin-resistant strains. Immunofluorescence assays showed its localization in the cytoplasm and on the surface of sporozoites. To elucidate the role of EtPFK1 in maduramycin-resistant strains, an EtPFK1-overexpressing strain was generated using the drug-sensitive strain of E. tenella. Overexpression of EtPFK1 reduced the sensitivity of E. tenella to maduramycin, as demonstrated by both in vitro and in vivo assays. Specifically, the EtPFK1-overexpressing strain exhibited complete resistance to 2 ppm maduramycin and light resistance to 5 ppm, indicating that EtPFK1 contributes to the development of drug resistance in E. tenella. Additionally, EtPFK1 overexpression reduced the pathogenicity of E. tenella, as demonstrated by fewer cecal lesions and lower oocyst output in infected chickens. EtPFK1 overexpression enhanced adaptation to high-glucose environments, potentially facilitating drug resistance. These findings highlight the multifaceted role of EtPFK1 in mediating drug resistance in E. tenella and provide insight into the development of novel therapeutic interventions against coccidiosis.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953008","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":"Comparative population genetics of the Antarctic grenadier fish (Macrourus whitsoni) and its parasitic copepod (Lophoura szidati).","authors":"Vahid Sepahvand, Miles D Lamare, Ceridwen I Fraser","doi":"10.1016/j.ijpara.2025.08.005","DOIUrl":"https://doi.org/10.1016/j.ijpara.2025.08.005","url":null,"abstract":"<p><p>Large ectoparasitic copepods, nearly as long as the length of their host, are often found on Antarctic fish, yet little is known about their biology. In this study, we investigated the genetic structure and host-parasite relationships in Macrourus whitsoni, a deep-sea fish, and its copepod ectoparasite, Lophoura szidati, using 10,569 biallelic SNPs collected from 38 copepods and 5,009 biallelic SNPs from 35 fish individuals across three populations in the Ross Sea, Antarctica. The Fst, DAPC, and admixture analyses revealed distinct genetic patterns between the two species. For M. whitsoni, our results demonstrated low to moderate genetic differentiation among populations, while L. szidati exhibited strong population structure. Nucleotide diversity (π) differed significantly among both fish host and copepod parasite populations, reflecting contrasting patterns of genetic variation. Tajima's D values were consistently negative in both hosts and parasites, indicating an excess of rare alleles, which suggests recent population expansion or purifying selection. Analysis of host-parasite coevolution revealed both congruent and discordant patterns. While some host-parasite pairs showed strong congruence, suggesting possible specialized coevolutionary relationships, other associations showed signs of discordance, suggesting host-switching events or ecological divergence. The contrasting genetic patterns and coevolutionary dynamics in our study open new directions for future research to show how life history traits, dispersal capacity, and environmental factors influence the biology and evolution of host-parasite species in the unique and extreme Ross Sea.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144953026","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":"Genetically tractable rodent models for Cryptosporidium hominis and C. parvum infections: identifying differences in infection sites between host species.","authors":"Lianbei Sun, Wei He, Zuwei Yang, Yilin Wu, Jing Wang, Na Li, Yaqiong Guo, Rui Xu, Jiayu Li, Yaoyu Feng, Lihua Xiao","doi":"10.1016/j.ijpara.2025.08.003","DOIUrl":"10.1016/j.ijpara.2025.08.003","url":null,"abstract":"<p><p>Cryptosporidiosis causes severe diarrhea in children and livestock. However, the absence of suitable rodent models has led to a lack of effective drugs and vaccines. In this study, genetically tractable rat and mouse models were developed for the two main causes of human cryptosporidiosis: Cryptosporidium hominis and C. parvum. Neonatal mice and rats were successfully infected with two nonhuman primate-adapted C. hominis isolates and one C. parvum IId isolate, resulting in high oocyst shedding. Using isolates tagged with fluorescent proteins and luciferases enabled the easy detection and quantification of oocyst shedding. Both Cryptosporidium species primarily infected the ileum, cecum, and colon of neonatal mice. In contrast, the parasites primarily colonized the duodenum and jejunum of neonatal rats. Both species responded to treatment with a lysyl-tRNA synthetase inhibitor in the rat model. Developing tractable animal models with different infection sites will allow for comparative studies of the biology and immunity of major human-pathogenic Cryptosporidium species, as well as the evaluation of potential drugs and vaccines.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144862146","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":"Testing the host specificity hypothesis: delimitation of Gyrodactylus species infecting fishes of the family Profundulidae across their distribution range.","authors":"Miguel Calixto-Rojas, Miguel Rubio-Godoy, Ismael Guzmán-Valdivieso, Juan J Barrios-Gutiérrez, Carlos D Pinacho-Pinacho","doi":"10.1016/j.ijpara.2025.08.001","DOIUrl":"10.1016/j.ijpara.2025.08.001","url":null,"abstract":"<p><p>Host specificity, a trait describing how many different hosts a parasite can infect, ranges from strict specialists for parasites associated to a single host species, to generalists for those able to infect several host species, which may even be phylogenetically unrelated. Monogenea are generally considered to be specialist parasites, but this appreciation may be an artifact arising from biased or limited sampling. Here, we evaluate host specificity of species of Gyrodactylus infecting fishes of the family Profundulidae collected in southern Mexico and, crucially, encompassing the whole distribution range of seven profundulid species. We used several molecular species delimitation methods to identify parasite lineages, which consistently recovered six species, four previously known and two new species, which we describe here. Gyrodactylid species infected from one to seven profundulid fish species, spanning the whole range of recognized host specificity associations, from strict specialists to generalists. No clear pattern could be discerned in the host-parasite associations we analysed (phylogenetic, host, geographical), suggesting that the ecological and evolutionary history of Gyrodactylus transcends that of their hosts - and one can envisage that with progressively more in-depth studies, it will be increasingly more difficult to speak of \"general\" patterns within large and complex groups of parasites, like the genus Gyrodactylus (Monogenea).</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144845893","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":"Live-attenuated Toxoplasma gondii PruΔpp2a-c mutant elicits protective immunity against toxoplasmosis in mice and cats.","authors":"Shi-Chen Xie, Yi-Han Lv, Meng Wang, Xiao-Nan Zheng, Jin-Lei Wang, Bao-Quan Fu, Xing-Quan Zhu","doi":"10.1016/j.ijpara.2025.08.002","DOIUrl":"10.1016/j.ijpara.2025.08.002","url":null,"abstract":"<p><p>Toxoplasma gondii is a zoonotic protozoan pathogen capable of infecting humans and nearly all warm-blooded animals, and causing substantial economic losses to the livestock industry. Developing an effective vaccine against T. gondii remains an urgent priority for controlling the spread of this zoonotic parasite. In this study, we evaluated the protective efficacy of a live-attenuated T. gondii PruΔpp2a-c mutant in both mice and cats. Immunization with PruΔpp2a-c elicited strong cellular (IL-2, IL-4, IL-10, IL-12, and IFN-γ) and humoral (IgG, IgG1, and IgG2a) immune responses in mice, conferring protection against lethal challenge with various T. gondii strains, including highly virulent Type I (RH), mildly virulent ToxoDB#9 (PYS), and less virulent Type II (Pru) strains. While partial protection was observed against virulent strains, almost complete immune protection was achieved against both acute and chronic infections by the less virulent Pru strain, along with a significant reduction in brain cyst burden (P < 0.001). Notably, vaccination of cats with PruΔpp2a-c induced high antibody titers and led to a 94.5 % reduction in fecal oocyst shedding (P < 0.001) following homologous challenge, thereby significantly decreasing the potential for environmental transmission. These findings demonstrate that PruΔpp2a-c provides strong cross-protection against various T. gondii strains and substantially limits oocyst shedding. The dual efficacy observed in both intermediate and definitive hosts highlights PruΔpp2a-c as a promising live-attenuated vaccine candidate for preventing transmission of T. gondii by cats.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144812013","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":"One of us survived: persistence of a syringophilid mite after Passenger Pigeon extinction.","authors":"Maciej Skoracki, Markus Unsoeld, Milena Patan, Bozena Sikora","doi":"10.1016/j.ijpara.2025.07.005","DOIUrl":"10.1016/j.ijpara.2025.07.005","url":null,"abstract":"<p><p>The current global biodiversity loss crisis affects not only avifauna but also associated parasites. Studies on museum specimens of extinct birds provide valuable insights into the species diversity, ecology, and evolution of parasitofauna, as well as determining whether specific parasite species have survived or become extinct alongside their hosts. In this study, we present the results of the examination of museum dry skins of the Passenger Pigeon Ectopistes migratorius (Linnaeus) (Columbiformes: Columbidae), which had been extremely common in North America until its extinction at the beginning of the 20th century. Studies revealed the presence of the representative of the family Syringophilidae, Meitingsunes zenadourae Clark (Prostigmata: Cheyletoidea), within the quill feathers of this host. This quill mite is a well-known parasite of multiple pigeon species across different genera of the order Columbiformes. The stenoxenic nature of M. zenadourae has likely contributed to its survival despite the extinction of E. migratorius.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144798994","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}