International journal for parasitology最新文献

{"title":"German Ixodes inopinatus samples may not actually represent this tick species","authors":"Robert E. Rollins ,&nbsp;Gabriele Margos ,&nbsp;Andreas Brachmann ,&nbsp;Stefan Krebs ,&nbsp;Alexia Mouchet ,&nbsp;Niels J. Dingemanse ,&nbsp;AbdElkarim Laatamna ,&nbsp;Nassiba Reghaissia ,&nbsp;Volker Fingerle ,&nbsp;Dirk Metzler ,&nbsp;Noémie S. Becker ,&nbsp;Lidia Chitimia-Dobler","doi":"10.1016/j.ijpara.2023.06.007","DOIUrl":"10.1016/j.ijpara.2023.06.007","url":null,"abstract":"<div><p>Ticks are important vectors of human and animal pathogens, but many questions remain unanswered regarding their taxonomy. Molecular sequencing methods have allowed research to start understanding the evolutionary history of even closely related tick species. <em>Ixodes inopinatus</em> is considered a sister species and highly similar to <em>Ixodes ricinus</em>, an important vector of many tick-borne pathogens in Europe, but identification between these species remains ambiguous with disagreement on the geographic extent of <em>I. inopinatus</em>. In 2018–2019, 1583 ticks were collected from breeding great tits (<em>Parus major</em>) in southern Germany, of which 45 were later morphologically identified as <em>I. inopinatus.</em> We aimed to confirm morphological identification using molecular tools. Utilizing two genetic markers (16S rRNA, TROSPA) and whole genome sequencing of specific ticks (<em>n</em> = 8), we were able to determine that German samples, morphologically identified as <em>I. inopinatus</em>, genetically represent <em>I. ricinus</em> regardless of previous morphological identification, and most likely are not <em>I. ricinus</em>/<em>I. inopinatus</em> hybrids. Further, our results showed that the entire mitochondrial genome, let alone singular mitochondrial genes (i.e., 16S), is unable to distinguish between <em>I. ricinus</em> and <em>I. inopinatus</em>. Our results suggest that <em>I. inopinatus</em> is geographically isolated as a species (northern Africa and potentially southern Spain and Portugal) and brings into question whether <em>I. inopinatus</em> exists in central Europe. Our results highlight the probable existence of <em>I. inopinatus</em> and the power of utilizing genomic data in answering questions regarding tick taxonomy.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 13","pages":"Pages 751-761"},"PeriodicalIF":4.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9937478","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":"Host specificity of coral-associated fauna and its relevance for coral reef biodiversity","authors":"Roeland J. van der Schoot ,&nbsp;Bert W. Hoeksema","doi":"10.1016/j.ijpara.2023.09.002","DOIUrl":"10.1016/j.ijpara.2023.09.002","url":null,"abstract":"<div><p>Coral-associated fauna predominantly consists of invertebrates and constitutes an important component of coral reef biodiversity. The symbionts depend on their hosts for food, shelter and substrate. They may act as parasites by feeding on their hosts, by overgowing their polyps, or by excavating their skeletons. Because some of these species partly reside inside their hosts, they may be cryptic and can easily be overlooked in biodiversity surveys. Since no quantitative overview is available about these inter-specific relationships, this present study adresses variation in host ranges and specificity across four large coral-associated taxa and between the Atlantic and Indo-Pacific oceans. These taxa are: coral barnacles (Pyrgomatidae, <em>n</em> = 95), coral gall crabs (Cryptochiridae, <em>n</em> = 54), tubeworms (Serpulidae, <em>n</em> = 31), and date mussels (Lithophaginae, <em>n</em> = 23). A total of 335 host coral species was recorded. An index of host specificity (<em>S</em>_TD) was calculated per symbiont species, based on distinctness in taxonomic host range levels (species, genus, family, etc.). Mean indices were statistically compared among the four associated taxa and the two oceanic coral reef regions. Barnacles were the most host-specific, tubeworms the least. Indo-Pacific associates were approximately 10 times richer in species and two times more host-specific than their Atlantic counterparts. Coral families varied in the number of associates, with some hosting none. This variation could be linked to host traits (coral growth form, maximum host size) and is most probably also a result of the evolutionary history of the interspecific relationships.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 2","pages":"Pages 65-88"},"PeriodicalIF":4.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S002075192300190X/pdfft?md5=3d9c7590cd71d15a64bb82d9d17d22ec&pid=1-s2.0-S002075192300190X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41199877","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":"A newly characterized dense granule protein (GRA76) is important for the growth and virulence of Toxoplasma gondii","authors":"Xiao-Nan Zheng ,&nbsp;Li-Xiu Sun ,&nbsp;Hany M. Elsheikha ,&nbsp;Ting-Ting Li ,&nbsp;Jin Gao ,&nbsp;Xiao-Jing Wu ,&nbsp;Zhi-Wei Zhang ,&nbsp;Meng Wang ,&nbsp;Bao-Quan Fu ,&nbsp;Xing-Quan Zhu ,&nbsp;Jin-Lei Wang","doi":"10.1016/j.ijpara.2023.09.001","DOIUrl":"10.1016/j.ijpara.2023.09.001","url":null,"abstract":"<div><p>Pathogenicity of the zoonotic pathogen <em>Toxoplasma gondii</em> largely depends on the secretion of effector proteins into the extracellular milieu and host cell cytosol, including the dense granule proteins (GRAs). The protein-encoding gene TGME49_299780 was previously identified as a contributor to parasite fitness. However, its involvement in parasite growth, virulence and infectivity in vitro and in vivo remains unknown. Here, we comprehensively examined the role of this new protein, termed GRA76, in parasite pathogenicity. Subcellular localization revealed high expression of GRA76 in tachyzoites inside the parasitophorous vacuole (PV). However, its expression was significantly decreased in bradyzoites. A CRISPR-Cas9 approach was used to knock out the <em>gra76</em> gene in the <em>T. gondii</em> type I RH strain and type II Pru strain. The in vitro plaque assays and intracellular replication showed the involvement of GRA76 in replication of RH and Pru strains. Deletion of the <em>gra76</em> gene significantly decreased parasite virulence, and reduced the brain cyst burden in mice. Using RNA sequencing, we detected a significant increase in the expression of bradyzoite-associated genes such as BAG1 and LDH2 in the PruΔ<em>gra76</em><span> strain compared with the wild-type Pru strain. Using an in vitro bradyzoite differentiation assay, we showed that loss of GRA76 significantly increased the propensity for parasites to form bradyzoites. Immunization with PruΔ</span><em>gra76</em> conferred partial protection against acute and chronic infection in mice. These findings show the important role of GRA76 in the pathogenesis of <em>T. gondii</em> and highlight the potential of PruΔ<em>gra76</em> as a candidate for a live-attenuated vaccine.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 2","pages":"Pages 109-121"},"PeriodicalIF":4.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41199876","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":"Compositional and phylogenetic nestedness of host assemblages exploited by generalist ectoparasites across their geographic ranges: drivers and associations with ectoparasite traits","authors":"Boris R. Krasnov ,&nbsp;Georgy I. Shenbrot ,&nbsp;Irina S. Khokhlova","doi":"10.1016/j.ijpara.2023.04.003","DOIUrl":"10.1016/j.ijpara.2023.04.003","url":null,"abstract":"<div><p>We investigated compositional and phylogenetic nestedness in the host assemblages of 26 host-generalist fleas across regions within the Palearctic. We asked the following questions: (i) are host assemblages exploited by a flea species compositionally or phylogenetically nested (=C-nested and P-nested, respectively) across regions?; (ii) if yes, what are the processes that generate nestedness, and does phylogenetic nestedness follow the same processes as compositional nestedness?; and (iii) are the biological traits of a flea species associated with its host assemblages’ degree of nestedness? Nestedness was calculated for matrices with rows ordered either by decreasing region area (=a-matrices) or increasing distance from the centre of a flea’s geographic range (d-matrices). Significant C-nestedness was found in either a- (three fleas) or d-matrices (three fleas) or both (10 fleas). Significant P-nestedness was detected in either a- (three fleas) or d-matrices (four fleas) or both (two fleas). In some but not other species, P-nestedness followed C-nestedness. The probability of C-nestedness to be significant, as well as its degree for d-matrices, was associated with a flea’s morphoecological traits, whereas this was not the case for either a-matrices or the P-nestedness for either type of ordered matrices. We conclude that compositional, but not phylogenetic, nestedness is (i) generated by similar mechanisms in many flea species and (ii) may be simultaneously driven by different mechanisms in the same flea. In contrast, mechanisms promoting phylogenetic nestedness differ between flea species and seem to act separately.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 663-672"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10261970","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":"Longitudinal follow-up reveals occurrence of successive Cryptosporidium bovis and Cryptosporidium ryanae infections by different subtype families in dairy cattle","authors":"Kangli Feng ,&nbsp;Na Li ,&nbsp;Yujin Huang ,&nbsp;Chengyi Chen ,&nbsp;Luxing Wen ,&nbsp;Weijian Wang ,&nbsp;Una M. Ryan ,&nbsp;Lihua Xiao ,&nbsp;Yaoyu Feng ,&nbsp;Yaqiong Guo","doi":"10.1016/j.ijpara.2023.04.005","DOIUrl":"10.1016/j.ijpara.2023.04.005","url":null,"abstract":"<div><p><em>Cryptosporidium bovis</em> and <em>Cryptosporidium ryanae</em> are common species causing cryptosporidiosis in cattle. Data accumulated thus far indicate that the infection patterns of the two species could be different between areas with and without <em>Cryptosporidium parvum</em>. To better understand the infection dynamics of these two species, cross-sectional and longitudinal studies of <em>Cryptosporidium</em> spp. were conducted using genotyping and subtyping tools. In the cross-sectional survey, analysis of 634 faecal samples from two farms identified only <em>C. bovis</em> and <em>C. ryanae</em> in pre-weaned calves. Two birth cohorts of 61 and 78 calves were followed longitudinally over a 12 month period, which revealed the shedding of <em>C. bovis</em> oocysts started at 1–2 weeks of age and peaked initially at 6–8 weeks of age. Altogether calves experienced four infections by six subtype families of <em>C. bovis</em>, with each infection caused by different subtype families. In contrast, the shedding of <em>C. ryanae</em> oocysts started at 2–4 weeks of age, and the two infections were caused by different subtype families. The cumulative incidence of <em>C. bovis</em> infection was 100% (58/58, 32/32) on both farms, compared with 84.4–98.3% (27/32 and 57/58) for <em>C. ryanae</em> infection. Overall, the mean duration of oocyst shedding in the cohort studies was 3.8–4.0 weeks for <em>C. bovis</em> compared with 2.1 weeks for <em>C. ryanae</em>. The oocyst shedding intensity was high (mean oocysts per gram of faeces was over 10⁵) during the first infection with each species but became significantly lower in the later infections. <em>Cryptosporidium ryanae</em> was associated with the occurrence of diarrhea on one farm, while <em>C. bovis</em> was not. The data indicate that there is an early occurrence of <em>C. bovis</em> and <em>C. ryanae</em> in pre-weaned calves with high infection intensity in the absence of <em>C. parvum.</em> Calves infected with the same <em>Cryptosporidium</em> sp. multiple times could be associated with the presence of subtype-specific immunity.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 651-661"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10206312","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":"MicroRNA-1 targets ribosomal protein genes to regulate the growth, development and reproduction of Schistosoma japonicum","authors":"Chengsong Sun ,&nbsp;Fang Luo ,&nbsp;Yanmin You ,&nbsp;Mengjie Gu ,&nbsp;Wenbin Yang ,&nbsp;Cun Yi ,&nbsp;Wei Zhang ,&nbsp;Zheng Feng ,&nbsp;Jipeng Wang ,&nbsp;Wei Hu","doi":"10.1016/j.ijpara.2023.03.007","DOIUrl":"10.1016/j.ijpara.2023.03.007","url":null,"abstract":"<div><p>Eggs laid by mature female schistosomes are primarily responsible for the pathogenesis of schistosomiasis and critical for transmission. Consequently, elucidating the mechanism of sexual maturation as well as egg production may lead to new strategies for the control of schistosomiasis. MicroRNAs (miRNAs) are involved in multiple biological processes including reproduction in many organisms, yet their roles have not been well characterized in schistosomes. Here, we investigated microRNA-1 (<em>miR-1</em>), which was downregulated gradually in both male and female <em>Schistosoma japonicum</em> after they reached sexually maturity. The expression of <em>miR-1</em>, as shown with quantitative reverse transcription PCR (qRT-PCR), was lower in the reproductive organs of adult females compared with the somatic tissues. Overexpression of <em>miR-1</em> in adult worms destroyed the morphological architecture of reproductive organs and reduced the subsequent oviposition, which may be due to the activation of apoptosis pathways. Through in silico analysis, 34 potential target genes of <em>miR-1</em> were identified, including five ribosomal protein genes, called <em>rp-s13</em>, <em>rp-l7ae</em>, <em>rp-l14</em>, <em>rp-l11</em> and <em>rp-s24e</em>. In vitro dual-luciferase reporter gene assays and miRNA overexpression experiments further validated that these ribosomal protein genes were directly regulated by <em>miR-1</em>. In contrast to the gene expression of <em>miR-1</em>, qRT-PCR and in situ hybridization experiments demonstrated these ribosomal protein genes were enriched in the sexual organs of adult females. Using RNA interference to silence the ribosomal protein genes in different developmental stages in a mouse model system, we demonstrated that these <em>miR-1</em> target genes not only participated in the reproductive development of <em>S. japonicum</em>, but also were required for the growth and survival of the parasite in the early developmental stages. Taken together, our data suggested that <em>miR-1</em> may affect the growth, reproduction and oviposition of <em>S. japonicum</em> by targeting the ribosomal protein genes, which provides insights for exploration of new anti-schistosome strategies.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 637-649"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10198091","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":"Molecular characterization of Blastocystis and Entamoeba of muskoxen and sheep in Greenland","authors":"Christen Rune Stensvold ,&nbsp;Rebecca P.K.D. Berg ,&nbsp;Jenny G. Maloney ,&nbsp;Aleksey Molokin ,&nbsp;Monica Santin","doi":"10.1016/j.ijpara.2023.05.005","DOIUrl":"10.1016/j.ijpara.2023.05.005","url":null,"abstract":"<div><p>Molecular characterisation of endobionts that are shared among human and non-human hosts can help shed light on the epidemiology and inform studies that aim to unravel the role of these organisms in health and disease. Two of the most common of shared endobionts include the single-celled intestinal protists <em>Blastocystis</em> and <em>Entamoeba</em>. Here, we present the first known data on genetic diversity and host specificity of these two genera in Greenland. Faecal DNA samples from 243 muskoxen and 44 sheep were submitted to metabarcoding of nuclear small subunit ribosomal DNA. <em>Entamoeba-</em> and <em>Blastocystis</em>-specific sequences were clustered, and consensus sequences were subjected to taxonomic query. Using MinION-based sequencing, near-complete nuclear small subunit ribosomal DNA sequences were obtained from four faecal samples. Of the 243 muskox samples, 180 (74%) and 19 (8%) were positive for <em>Blastocystis</em> and <em>Entamoeba</em>, respectively. Forty (91%) and six (14%) of the 44 sheep samples were positive for <em>Blastocystis</em> and <em>Entamoeba</em>, respectively. <em>Blastocystis</em> subtypes (ST) 10, 14, 21, 24–26, and a novel subtype (ST40) were identified. Colonisation by more than one subtype was common. ST40 was common in muskoxen but limited to Northeast Greenland. <em>Entamoeba bovis</em> and the <em>E. bovis</em><span>-associated ribosomal lineages (RL) 1 and 8 were found, and three conditional lineages (CL) 3, 4, and 10 were confirmed; CL10 was promoted to RL12. Several novel lineages were identified, all of which were linked to the </span><em>E. bovis</em> complex. In conclusion, <em>Blastocystis</em> was far more common than <em>Entamoeba</em> and found in approximately three of every four animals; both can be considered common colonisers of large herbivorous mammals in Greenland. Multiple subtypes/lineages of both genera were commonly observed, some of which were novel, but most of which are seen in many other parts of the world.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 673-685"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10204818","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":"Morphological constraint obscures richness: a mitochondrial exploration of cryptic richness in Transversotrema (Trematoda: Transversotrematidae)","authors":"Scott C. Cutmore ,&nbsp;Richard D. Corner ,&nbsp;Thomas H. Cribb","doi":"10.1016/j.ijpara.2023.06.006","DOIUrl":"10.1016/j.ijpara.2023.06.006","url":null,"abstract":"<div><p>Species of <em>Transversotrema</em> Witenberg, 1944 (Transversotrematidae) occupy a unique ecological niche for the Trematoda, living externally under the scales of their teleost hosts. Previous studies of the genus have been impeded partly by limited variation in ribosomal DNA sequence data between closely related species and partly by a lack of morphometrically informative characters. Here, we assess richness of the tropical Indo-west Pacific species through parallel phylogenetic and morphometric analyses, generating cytochrome c oxidase subunit 1 mitochondrial sequence data and morphometric data for hologenophore specimens from Australia, French Polynesia, Japan and Palau. These analyses demonstrate that molecular data provide the only reliable basis for species identification; host distribution, and to a lesser extent morphology, are useful for identifying just a few species of <em>Transversotrema</em>. We infer that a combination of morphological simplicity and infection site constraint has led to the group displaying exceptionally low morphological diversification. Phylogenetic analyses of the mitochondrial data broadly support previous systematic interpretations based on ribosomal data, but also demonstrate the presence of several morphologically and ecologically cryptic species. Ten new species are described, eight from the Great Barrier Reef, Australia (<em>Transversotrema chrysallis</em> n. sp., <em>Transversotrema daphnidis</em> n. sp., <em>Transversotrema enceladi</em> n. sp., <em>Transversotrema hyperionis</em> n. sp., <em>Transversotrema iapeti</em> n. sp., <em>Transversotrema rheae</em> n. sp., <em>Transversotrema tethyos</em> n. sp., and <em>Transversotrema titanis</em> n. sp.) and two from off Japan (<em>Transversotrema methones</em> n. sp. and <em>Transversotrema panos</em> n. sp.). There are now 26 <em>Transversotrema</em> species known from Australian marine fishes, making it the richest trematode genus for the fauna.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 595-635"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10205850","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":"Multinomial logistic regression based on neural networks reveals inherent differences among dairy farms depending on the differential exposure to Fasciola hepatica and Ostertagia ostertagi","authors":"Andreas W. Oehm ,&nbsp;Markus Leinmueller ,&nbsp;Yury Zablotski ,&nbsp;Amely Campe ,&nbsp;Martina Hoedemaker ,&nbsp;Andrea Springer ,&nbsp;Daniela Jordan ,&nbsp;Christina Strube ,&nbsp;Gabriela Knubben-Schweizer","doi":"10.1016/j.ijpara.2023.05.006","DOIUrl":"10.1016/j.ijpara.2023.05.006","url":null,"abstract":"<div><p><em>Fasciola hepatica</em> and <em>Ostertagia ostertagi</em> are cattle parasites with worldwide relevance for economic outcome as well as animal health and welfare. The on-farm exposure of cattle to both parasites is a function of host-associated, intrinsic, as well as environmental and farm-specific, extrinsic, factors. Even though knowledge on the biology of both parasites exists, sophisticated and innovative modelling approaches can help to deepen our understanding of key aspects fostering the exposure of dairy cows to these pathogens. In the present study, multiple multinomial logistic regression models were fitted via neural networks to describe the differences among farms where cattle were not exposed to either <em>F. hepatica</em> or <em>O. ostertagi</em>, to one parasite, or to both, respectively. Farm-specific production and management characteristics were used as covariates to portray these differences. This elucidated inherent farm characteristics associated with parasite exposure. In both studied regions, pasture access for cows, farm-level milk yield, and lameness prevalence were identified as relevant factors. In region ‘South’, adherence to organic farming principles was a further covariate of importance. In region ‘North’, the prevalence of cows with a low body condition score, herd size, hock lesion prevalence, farm-level somatic cell count, and study year appeared to be of relevance. The present study broadens our understanding of the complex epidemiological scenarios that could predict differential farm-level parasite status. The analyses have revealed the importance of awareness of dissimilarities between farms in regard to the differential exposure to <em>F. hepatica</em> and <em>O. ostertagi</em>. This provides solid evidence that dynamics and relevant factors differ depending on whether or not cows are exposed to <em>F. hepatica, O. ostertagi</em>, or to both.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"53 11","pages":"Pages 687-697"},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10198095","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":"Functional characterization of a conserved membrane protein, Pbs54, involved in gamete fertilization in Plasmodium berghei","authors":"Wei Pang ,&nbsp;Jie Bai ,&nbsp;Liying Zhu ,&nbsp;Fei Liu ,&nbsp;Yudi Wu ,&nbsp;Fan Yang ,&nbsp;Li Zheng ,&nbsp;Pengbo Liu ,&nbsp;Yaowen Zhang ,&nbsp;Meilian Wang ,&nbsp;Jun Li ,&nbsp;Xiaotong Zhu ,&nbsp;Liwang Cui ,&nbsp;Yaming Cao","doi":"10.1016/j.ijpara.2023.08.003","DOIUrl":"10.1016/j.ijpara.2023.08.003","url":null,"abstract":"<div><p>The successful completion of gamete fertilization is essential for malaria parasite transmission, and this process can be targeted by intervention strategies. In this study, we identified a conserved gene (PBANKA_0813300) in the rodent malaria parasite <em>Plasmodium berghei</em>, which encodes a protein of 54 kDa (designated as Pbs54). Localization studies indicated that Pbs54 is associated with the plasma membranes of gametes and ookinetes. Functional studies by gene disruption showed that the <em>Δpbs54</em> parasites had no defect in asexual proliferation, gametocyte development, or gametogenesis. However, the interactions between male and female gametes were significantly decreased compared with wild-type parasites. The <em>Δpbs54</em> lines did not show a further reduction in zygote and ookinete numbers during in vitro culture, indicating that the defects were probably restricted to gamete fertilization. Consistent with this finding, mosquitoes fed on <em>Δpbs54</em>-infected mice showed a 30.1% reduction in infection prevalence and a 74.7% reduction in oocyst intensity. Cross-fertilization assay indicated that both male and female gametes were impaired in the <em>Δpbs54</em> parasites. To evaluate its transmission-blocking potential, we obtained polyclonal antibodies from mice immunized with the recombinant Pbs54 (rPbs54) protein. In vitro assays showed that anti-rPbs54 sera inhibited ookinete formation by 42.7%. Our experiments identified Pbs54 as a fertility factor required for mosquito transmission and a novel candidate for a malaria transmission-blocking vaccine.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 2","pages":"Pages 99-107"},"PeriodicalIF":4.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41123160","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}