Journal of invertebrate pathology最新文献

{"title":"Characterization and functional analysis of the small heat shock protein HSP19.5 in Bombyx mori in response to Nosema bombycis infection","authors":"Zhenghao Han ,&nbsp;Shidong Jiang ,&nbsp;Jingxian Xie ,&nbsp;Ibouanga Sama Lucreche Poupina ,&nbsp;Xiaoli Mo ,&nbsp;Li Sui ,&nbsp;Ping Qian ,&nbsp;Xudong Tang","doi":"10.1016/j.jip.2025.108289","DOIUrl":"10.1016/j.jip.2025.108289","url":null,"abstract":"<div><div>Small heat shock proteins (sHSPs) are molecular chaperones known for their role in maintaining cellular homeostasis and protecting cells from various environmental stresses. This study focuses on the silkworm small heat shock protein HSP19.5 and its potential functions in the context of <em>Nosema bombycis</em> infection, a microsporidian pathogen causing severe disease in the sericulture industry. We cloned and characterized <em>HSP19.5</em> and revealed its expression patterns in different silkworm tissues and developmental stages. Our results indicate that <em>HSP19.5</em> expression is significantly up-regulated in response to <em>N. bombycis</em> infection, suggesting a role in the host stress response. Through a series of experiments, including RNA interference and overexpression analyses, we demonstrated that HSP19.5 promotes <em>N. bombycis</em> proliferation, possibly by inhibiting host cell apoptosis and regulating intracellular ROS levels. The cytoplasmic localization of HSP19.5 in silkworm cells is consistent with its function as a molecular chaperone. The results enhance our understanding of the complex host-pathogen interactions between silkworms and <em>N. bombycis</em>, and provides insights that may inform the development of novel strategies to control the pebrine disease.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"210 ","pages":"Article 108289"},"PeriodicalIF":3.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and detection of known and new viruses in larvae of laboratory-reared fall armyworm, Spodoptera frugiperda","authors":"Leonardo A. da Silva ,&nbsp;Brenda R. de Camargo ,&nbsp;Andrews A.F.M.S. Fisch ,&nbsp;Bráulio Santos ,&nbsp;Daniel M.P. Ardisson-Araújo ,&nbsp;Bergmann M. Ribeiro","doi":"10.1016/j.jip.2025.108290","DOIUrl":"10.1016/j.jip.2025.108290","url":null,"abstract":"<div><div>The fall armyworm (FAW), <em>Spodoptera frugiperda</em>, is a significant pest that causes economic losses worldwide. Many companies and research centers rear FAW to produce their microbiological-based products, such as viruses that target FAW. Nevertheless, colonies are vulnerable to collapsing, mainly due to uncontrolled and unexpected viral infections. In this work, dead FAWs exhibiting signs of viral infection were collected from unsuccessful attempts to propagate a baculovirus at a baculovirus production facility in Brazil. Total RNA was extracted and used to construct a cDNA library that was sequenced. The results showed the presence of five viruses, including three RNA viruses (alphanodavirus, rhabdovirus, and iflavirus) and two DNA viruses (densovirus and alphabaculovirus). To confirm the presence of the identified viruses in laboratory-reared FAWs, ten individual larvae from four accredited laboratories in Brazil were analyzed by RT-PCR with specific primers for each virus identified by sequencing, except the alphabaculovirus. Alphanodavirus and rhabdovirus were not detected in any of the four tested colonies, whereas the iflavirus was detected in two laboratories. A putative new densovirus was found in all samples. Accurate identification and timely detection of viruses that could disrupt the health of laboratory-reared insect colonies are crucial to ensure the production of high-quality biological products.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"210 ","pages":"Article 108290"},"PeriodicalIF":3.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of a Snf7-domain-containing protein that exhibits high affinity and synergistic activity for Cry13Aa1 toxin in Bursaphelenchus xylophilus","authors":"Yajie Guo ,&nbsp;Lulu Huang ,&nbsp;Hang Zhang ,&nbsp;Jun Li ,&nbsp;Yanyue Zhou ,&nbsp;Yunzhu Sun ,&nbsp;Mingqing Weng ,&nbsp;Songqing Wu ,&nbsp;Chunlan Lian","doi":"10.1016/j.jip.2025.108279","DOIUrl":"10.1016/j.jip.2025.108279","url":null,"abstract":"<div><div>Pine wilt disease, caused by the pinewood nematode <em>Bursaphelenchus xylophilus</em> (Rhabditida: Aphelenchoididae), results in significant global economic and ecological impacts. Although the Cry13Aa1 toxin from <em>Bacillus thuringiensis</em> shows nematicidal activity, its mechanism of action against <em>B. xylophilus</em> remains unclear. This study aimed to identify and characterize the receptors for Cry13Aa1 in <em>B. xylophilus</em>. We cloned the cDNAs encoding an Snf7 domain-containing protein (<em>Bx</em>Snf7) from <em>B. xylophilus</em>. Far-western blot analysis revealed a specific binding interaction between <em>Bx</em>Snf7 and Cry13Aa1, showing a dissociation constant (<em>K</em>_d) of 20.8 ± 4.2 nM. Interestingly, bioassay results indicated that silencing <em>BxSnf7</em> increased the susceptibility of nematodes to Cry13Aa1 at higher concentrations, although the difference was not statistically significant. Besides, the combined application of <em>Bx</em>Snf7 with Cry13Aa1 significantly enhanced nematicidal mortality (95.9 %) after 24 h of treatment, which higher than the expected mortality (42.8 %) (χ² = 16.118, <em>P</em> = 0.048), indicating that the exogenous <em>Bx</em>Snf7 synergistically enhances the activity of Cry13Aa1 toxin. These findings identify <em>Bx</em>Snf7 as a novel Cry13Aa1 binding protein and reveal a unique mechanism by which <em>Bx</em>Snf7 synergistically enhances the activity of Cry13Aa1. However, <em>Bx</em>Snf7 does not function as the primary receptor, and further research is needed to investigate its role in modulating nematode susceptibility to Cry13Aa1.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"210 ","pages":"Article 108279"},"PeriodicalIF":3.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of insect odor cues and infective juvenile age on the host-seeking behavior of Steinernema siamkayai","authors":"Puping Ta-oun ,&nbsp;Toyoshi Yoshiga","doi":"10.1016/j.jip.2025.108280","DOIUrl":"10.1016/j.jip.2025.108280","url":null,"abstract":"<div><div>Entomopathogenic nematodes (EPNs) are soil-dwelling, insect-parasitic nematodes used in biological control. Infective juveniles (IJs), a third-stage free-living stage, are responsible for foraging and infecting suitable insect hosts, exhibiting cruising, ambushing, or intermediate foraging strategies. <em>Steinernema siamkayai</em>, an ambush forager, is a valuable biological control agent in Thailand, yet little is known about its behavioral response to host cues and insect odors. This study examines the olfactory responses of <em>S. siamkayai</em> IJs to insect odorants, including CO₂, compared to an ambusher, <em>S. carpocapsae</em>, and an intermediate forager, <em>S. monticolum</em>. Using a chemotaxis assay on agar plates, we found <em>S. siamkayai</em> and <em>S. monticolum</em> were attracted to insect odors, but attraction diminished when CO₂ was removed with soda lime, whereas <em>S. carpocapsae</em> showed minimal attraction. <em>S. siamkayai</em> and <em>S. monticolum</em> exhibited a stronger response to CO₂ than <em>S. carpocapsae</em>. Additionally, in a sand column assay assessing vertical movement, all three EPNs responded to insect odors from below, with odor response declining as IJ age increased, indicating age-related changes in host-seeking behavior. These results suggest that although <em>S. siamkayai</em> and <em>S. carpocapsae</em> are ambushers within the same phylogenetic clade, their host detection mechanisms differ.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"210 ","pages":"Article 108280"},"PeriodicalIF":3.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Untangling a web of spider fungi: Gibellula agroflorestalis (Hypocreales, Ascomycota), a new species of spider parasite from Brazil","authors":"Julie Erica da Rocha Alves,&nbsp;Ana Carla da Silva Santos,&nbsp;Sheila Karine Belo Pedroso,&nbsp;Roger Fagner Ribeiro Melo,&nbsp;Patricia Vieira Tiago","doi":"10.1016/j.jip.2025.108278","DOIUrl":"10.1016/j.jip.2025.108278","url":null,"abstract":"<div><div><em>Gibellula</em> (Cordycipitaceae) includes widely distributed spider pathogenic fungi. This study describes a novel species, <em>Gibellula agroflorestalis</em>, recorded in agroforestry systems (AFS) and Atlantic Forest remnants in Pernambuco State, northeastern Brazil. The morphology of synnemata and conidiophores was studied, and phylogenetic analyses used SSU, LSU and <em>TEF1</em> data in order to confirm the distinctiveness of the new species. The new species presents particular morphological characteristics, such as lacrimoid conidia and white synnemata. Comparison with other species in the genus revealed significant differences both in conidial and synnematal morphology. Based on Maximum Likelihood and Bayesian Inference phylogenies, <em>G. agroflorestalis</em> is a sister species to <em>G. pulchra</em>. The variations observed in the samples may be attributed to the microenvironmental conditions of AFS, which can influence phenotypic expression. This research emphasizes the importance of AFS in biodiversity conservation and in the discovery of new species.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108278"},"PeriodicalIF":3.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143229486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanopore reads spanning the whole genome of arthropod-infecting large dsDNA viruses of the class Naldaviricetes enable assembly-free sequence analysis","authors":"Jörg T. Wennmann","doi":"10.1016/j.jip.2025.108277","DOIUrl":"10.1016/j.jip.2025.108277","url":null,"abstract":"<div><div>The nuclear arthropod-specific large DNA viruses comprise different phylogenetically related virus families (<em>Baculoviridae</em>, <em>Nudiviridae</em>, <em>Hytrosaviridae</em> and <em>Nimaviridae</em>) forming the class <em>Naldaviricetes</em>. One common characteristic of their large double-stranded circularly and covalently closed DNA genomes is the size of up to hundreds of kilobase pairs, encoding up to hundreds of open reading frames. Until recently, analyzing such large viral dsDNA genomes was hampered by short read sequencing techniques, requiring bioinformatic assembly strategies to construct a consensus sequence as a descriptor of a population of haplotype sequences. The ideal aim for decoding large dsDNA genomes is an assembly-free method that allows the individual gnomes of a virus population to be sequenced in individual reads without fragmentation. Such full-length genome sequencing of single genome molecules is made possible by Nanopore sequencing, which is increasingly used to decode representatives of the <em>Naldaviricetes</em>. The present study discusses the impact of Nanopore sequencing on the characterization of viral NALDV populations. Full-length genome reads can be found in published sequence data from Bombyx mori nucleopolyhedrovirus (BmNPV; family <em>Baculoviridae</em>) and Oryctes rhinoceros nudivirus (OrNV; family <em>Nudiviridae</em>) isolates, providing insight into the future of deciphering populations of members of the order <em>Lefavirales</em> and class <em>Naldaviricetes</em>. Thirty years after the first sequencing of a baculovirus in 1994, a new era of sequencing of arthropod-infecting large dsDNA viruses has begun, which will allow assembly-free analysis of entire populations of large dsDNA viruses.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108277"},"PeriodicalIF":3.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143122933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the bacterial pathogen Pseudomonas protegens Pf-5 on the immune response of larvae of the black soldier fly, Hermetia illucens L.","authors":"Parth N. Shah ,&nbsp;Sevasti Maistrou ,&nbsp;Joop J.A. van Loon,&nbsp;Marcel Dicke","doi":"10.1016/j.jip.2025.108272","DOIUrl":"10.1016/j.jip.2025.108272","url":null,"abstract":"<div><div>The larvae of the black soldier fly (BSFL), <em>Hermetia illucens</em> L. (Diptera: Stratiomyidae), are exposed to a diverse range of microorganisms within their feeding substrate that is mainly composed of decaying organic matter. In the current study, we evaluated the effect of an interaction with a Gram-negative bacterium, <em>Pseudomonas protegens</em> Pf-5, on the immune responses of the larvae of <em>H. illucens.</em> Five-day-old BSF larvae were injected with one of five doses of bacterial inoculum to assess survival. We observed dose-dependent mortality in BSF larvae to <em>P. protegens</em> infection, with mortality increasing with an increasing pathogen dose. Injection of more than 50 bacterial cells per larva resulted in 100 % larval mortality, while injection of one bacterial cell per larva caused only 20 % mortality. Phenoloxidase activity, an element of the immune response, correlated with the pathogen dose, increasing early for larvae injected with a high pathogen dose (i.e., 5000 bacterial cells per larva) and later for larvae injected with a low bacterial dose (i.e., one cell per larva). The expression of four genes encoding for antimicrobial peptides (AMPs), namely <em>cecropin, defensin-A, defensin-like peptide 4</em>, and <em>attacin-A</em>, displayed a treatment- and dose-specific expression pattern. Injection with either PBS (control) or different bacterial doses initially induced the upregulation of AMP genes; however, expression reduced over time in the control larvae. At high pathogen dose, all tested genes except <em>hsp70</em> were consistently induced. The expression of all genes, except <em>hsp70</em>, was induced by low pathogen dose at 2 h, then reduced gradually and increased significantly at 15 h. These results collectively indicate that BSF larvae temporally modulate their immune responses, such as phenoloxidase activation and AMP gene expression, to combat a pathogen within their hemolymph.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108272"},"PeriodicalIF":3.6,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143080265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Candidate DNA and RNA viruses of Drosophila suzukii from Canada and Germany, and their interactions with Wolbachia","authors":"Jan P. Dudzic ,&nbsp;Audrey E. McPherson ,&nbsp;Keelie E. Taylor ,&nbsp;Astrid Eben ,&nbsp;Paul K. Abram ,&nbsp;Steve J. Perlman","doi":"10.1016/j.jip.2025.108274","DOIUrl":"10.1016/j.jip.2025.108274","url":null,"abstract":"<div><div>Some species of insects harbour strains of the endosymbiotic bacteria <em>Wolbachia</em> that do not cause obvious reproductive manipulations, and so it is unclear why they persist in host populations. There is some evidence that some of these endosymbionts may provide their hosts with protection against viruses, which would help to explain their persistence, but few studies have explored associations between <em>Wolbachia</em> and naturally occurring, common viruses in natural populations. Here, we asked whether individuals of the invasive vinegar fly <em>Drosophila suzukii</em> infected with the <em>wSuz</em> strain of <em>Wolbachia</em> were less likely to be infected by naturally occurring viruses in its invaded range, in western North America and in Europe. First, using next-generation sequencing, we conducted a virome survey of adult and larval <em>D. suzukii</em> in British Columbia, Canada, finding eight candidate RNA viruses and two candidate DNA viruses; all but one have not been reported previously. Only the previously described Teise virus, an RNA virus, was abundant in our virome survey. We then screened individual flies from British Columbia and Germany for Teise virus and <em>Wolbachia</em>. <em>Wolbachia</em>-infected <em>D. suzukii</em> from the field were not less likely to be infected by Teise virus. Overall, our results do not provide conclusive evidence that <em>wSuz</em> provides strong protection for <em>D. suzukii</em> against viruses that are common in natural populations. However, the other viruses that we discovered in this study deserve further characterization in terms of their pathogenicity to <em>D. suzukii</em> and the frequency and dynamics of infection in wild populations.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108274"},"PeriodicalIF":3.6,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143074806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occurrence and allele frequencies of genetic variants associated with Varroa drone brood resistance (DBR) in African Apis mellifera subspecies","authors":"Haftom Gebremedhn ,&nbsp;Regis Lefebre ,&nbsp;Moses Chemurot ,&nbsp;Felicien Amakpe ,&nbsp;Bezabeh Amssalu ,&nbsp;Lina De Smet ,&nbsp;Dirk C. de Graaf","doi":"10.1016/j.jip.2025.108276","DOIUrl":"10.1016/j.jip.2025.108276","url":null,"abstract":"<div><div>The ectoparasite <em>Varroa destructor</em> is a major contributor to the global decline of honeybee colonies (<em>Apis mellifera</em>), especially in the Northern Hemisphere. However, <em>Varroa</em>-resistant honeybee populations have been reported in various regions around the globe, including Europe and Africa. This resistance is primarily attributed to the trait known as Suppressed Mite Reproduction (SMR), which significantly reduces the reproductive success of <em>Varroa</em> mites within these colonies. Although this trait is still poorly understood, several efforts have been made to unravel the genetic basis of SMR. For example, a study in Belgium determined eight genetic variants in the honeybee genome that are associated with the infertility of mites in drone brood (Drone Brood Resistance or DBR). As these eight variants were found and validated in subpopulations of European subspecies only, there is limited knowledge about the occurrence of these markers in African honeybees. Hence, this study was designed to determine the allele frequencies of these eight genetic variants in African honeybee populations. More specifically, we used qPCR assays with dual-labeled probes to analyze bee samples collected from Benin, Ethiopia, and Uganda. Our results showed the presence of seven of the eight variants in African <em>Apis mellifera</em> subspecies, which may contribute to their innate resistance against the <em>Varroa</em> mite. Moreover, we found significant differences in allele frequencies among the three sampled African bee populations, suggesting the presence of genetic diversity within these populations, potentially altering their resistance to <em>Varroa</em>. This study revealed similar allele frequencies between African honeybees and bee samples from the European <em>iberiensis</em>-subspecies (A lineage), while Ethiopian bees showed distinct distributions, indicative of a unique lineage. Overall, the occurrence of most DBR-associated genetic variants in African honeybees opens research opportunities to elucidate the predictive properties and potential of these genetic variants in the African continent by examining genotype-phenotype associations.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108276"},"PeriodicalIF":3.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143066201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epidemiological insight into disseminated neoplasia in Mytilus chilensis from southern Chile","authors":"Karin B. Lohrmann ,&nbsp;Eduardo Bustos ,&nbsp;Rosanna Rojas ,&nbsp;Hugo Robotham ,&nbsp;Ana L. Valdivia ,&nbsp;Florencia Navarrete ,&nbsp;Juan F. Quiroga ,&nbsp;Karin Veloso-Mardones ,&nbsp;Ivonne Lee-Montero","doi":"10.1016/j.jip.2025.108273","DOIUrl":"10.1016/j.jip.2025.108273","url":null,"abstract":"<div><div>This study investigates the prevalence and characteristics of disseminated neoplasia (DN) in <em>Mytilus chilensis</em> in the Los Lagos Region of southern Chile. DN is a malignant proliferative disease that has been described in several species of the genus <em>Mytilus.</em> More than 4.000 adult mussels, both cultured and natural, collected between 2016 and 2022 in different geographical areas (Calbuco-Hueihue, Castro, Quellón) and seasons (winter-spring, summer-autumn) were histologically analysed. The prevalence was assessed and three levels of severity of DN were defined, based on number of neoplastic cells and organs invaded. Morphology and morphometry of neoplastic cells and hemocytes were evaluated. Cell and nucleus diameters and the nucleus/cytoplasm ratio of granulocytes and hyalinocytes were analysed in healthy and neoplastic individuals. The size of neoplastic cells was significantly larger in stage 3 of neoplasia than in stage 1. The overall mean prevalence of DN in <em>M. chilensis</em> was 3.4%, significant differences were found between sites, being higher in Calbuco-Hueihue (5.59%) than in Castro (3.78%) and Quellón (1.40%). The prevalence was significantly higher in the winter-spring season (7.79%) than in the summer-autumn season (3.95%) in Calbuco-Hueihue. The sex, gametogenic stage, and Adipogranular (ADG) cells status were recorded for each mussel, and related to the severity stages of DN. For stages 1 and 2 of DN, females and males could be recognized, but in stage 3 almost no evidence of sex remained. The same trend was identified for the gonadal status, the advanced stages of DN were associated with castration of the mussels. The ADG cells status was highest at stage 1 of DN, declining in number and staining till stage 3. The sex ratio of healthy mussels was 53.5% female, 43.7% male, 1.6% hermaphrodite, and 1.3% indeterminate, for mussels with DN it was 34.1% female, 16% male, 2.2% hermaphrodite and 47.8% indeterminate. Occurrence of DN was higher in females, but the severity stages affected equally female and male mussels. Although the overall prevalence is low, there are some potential risks that warrant continued monitoring and further study of disseminated neoplasia in <em>M. chilensis</em>. This study provides important data on the epidemiology of DN in <em>M. chilensis</em>, which will inform future research and management strategies in aquaculture.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"209 ","pages":"Article 108273"},"PeriodicalIF":3.6,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143023752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}