Water Biology and Security最新文献

{"title":"A recombinase polymerase amplification with lateral flow assay for rapid on-the-spot detection of Aeromonas salmonicida","authors":"","doi":"10.1016/j.watbs.2024.100272","DOIUrl":"10.1016/j.watbs.2024.100272","url":null,"abstract":"<div><p><em>Aeromonas salmonicida</em> is a common pathogen of salmonid fishes that poses a significant threat to the fresh water and marine culture industry, potentially resulting in huge economic losses. To prevent and control fish diseases caused by <em>A. salmonicida</em>, rapid and effective diagnostic approaches must be developed, and which are important for routine monitoring and clinical care. By combining recombinase polymerase amplification (RPA) technology with a visible lateral flow strip (RPA-LF), we have enhanced both the precision of RPA detection and the convenience of real-time monitoring. In this study, we introduce a robust method for detecting <em>A. salmonicida</em> using RPA-LF. This assay specifically targets the ASA_1441 gene of <em>A. salmonicida</em>, ensuring high specificity, without cross-reactivity with other prevalent fresh water or marine pathogens. The optimal amplification temperature of the RPA assay was 39 ​°C. Its sensitivity extends to as low as 100 ​fg of purified DNA, representing more than 1000-fold higher sensitivity than conventional PCR methods. Furthermore, to enhance the usability of the RPA-LF assay, we developed a rapid sample preparation method using cellulose dipsticks for nucleic acid extraction. This method achieves a limit of detection (LOD) as low as 1.67 ​CFU/μL and completes the entire process within 20 ​min. In conclusion, our findings present a rapid and precise tool for monitoring <em>A. salmonicida</em> infection in aquaculture and marine culture. This advancement offers valuable insights for effective disease prevention and control strategies.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100272"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000337/pdfft?md5=126901cd7c2312fc1afeba1f805d4806&pid=1-s2.0-S2772735124000337-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141139412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity in freshwater scuticociliates (Alveolata, Ciliophora, Scuticociliatia): Two new species isolated from a wetland in northern China, focusing on their morphology, taxonomy, and molecular phylogeny, with establishment of a new family Glauconematidae fam. nov.","authors":"","doi":"10.1016/j.watbs.2024.100275","DOIUrl":"10.1016/j.watbs.2024.100275","url":null,"abstract":"<div><p>In the aquatic microbial food web, scuticociliates are diverse and predominant in almost all kinds of biotopes while extremely confused regarding their taxonomy and systematic relationships within the subclass Scuticociliatia. Here we provide detailed descriptions of two new and one known species, <em>Glauconema sinica</em> sp. nov., <em>Pleuronema parasetigerum</em> sp. nov., and <em>Histiobalantium natans viridis</em>, isolated from a freshwater wetland in northern China, along with their molecular phylogeny based on SSU rRNA gene sequences. Our results show: (1) both molecular and morphological data strongly support that the isolated lineage containing the genera <em>Glauconema</em>, <em>Miamiensis</em>, <em>Paramesanophrys</em>, and <em>Anophryoides</em> should be identified as a new taxon at the family level in the order Philasterida; hence, a new family, Glauconematidae fam. nov., is established. This new family is mainly characterized by the polymorphic life cycle of its members (macrostome and microstome stages); the trophont (or macrostome) has closely spaced membranelles 1–3, whereas in the tomite (or microstome) membranelle 1 is distant from membranelle 2. (2) Phylogenetic analyses using novel data for these species revealed that all three cluster with their congeners, supporting the validity of the genera to which they belong. Molecular information also supports the monophyly of the two main scuticociliate orders Pleuronematida and Philasterida.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100275"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000362/pdfft?md5=d440f26da58f3a6edfafb53c9107b4d2&pid=1-s2.0-S2772735124000362-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141391786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Species composition and succession of coral reef fishes in Huaguang Reef, Xisha Islands","authors":"Zhipeng Kang ,&nbsp;Teng Wang ,&nbsp;Chunhou Li ,&nbsp;Jinfa Zhao ,&nbsp;Juan Shi ,&nbsp;Hongyu Xie ,&nbsp;Yong Liu","doi":"10.1016/j.watbs.2024.100273","DOIUrl":"10.1016/j.watbs.2024.100273","url":null,"abstract":"<div><p>A list of coral reef fish species of Huaguang Reef was compiled in 2023 using hand fishing, diving fishing, underwater video, and eDNA detection, combined with historical data from 1979 and archival records from the South China Sea Fisheries Research Institute of the Chinese Academy of Fisheries Sciences for the years of 1998, 1999, 2003, and 2005. Successional characteristics of coral reef fishes through time were also explored. The findings revealed: (1) A total of 299 coral reef fish species were identified in Huaguang Reef, categorized into 2 classes, 16 orders, and 56 families, with Perciformes exhibiting the highest species count (234), constituting 78.26% of all species. (2) In comparison to the period of 1979–2005, there was a reduction in the number of species at the order and family levels in 2023 at Huaguang Reef. Both the average taxonomic distinctness (Δ+) and the variation in taxonomic distinctness (Λ+) exhibited a declining trend, indicating disturbances in the fish ecosystem. (3) The proportion of herbivorous fish at Huaguang Reef remained relatively stable in 2023 compared to the 1979–2005 period. Notably, the similarity coefficient of herbivorous fish was the highest among different feeding types, signifying a degraded state of the Huaguang Reef habitat. (4) In contrast to the 1979–2005 period, a significant decline was observed in large-sized and carnivorous fish species at Huaguang Reef in 2023. The low similarity coefficients for both categories, with undiscovered fish species accounting for 58.49% and 45.76% of their respective taxa in the total list, respectively, suggested a notable impact of overfishing on coral reef fishes. The succession patterns revealed in this study provide a theoretical foundation for advancing the sustainable development of coral reef fish resources in the Xisha Islands and offer valuable insights for the protection and management of coral reef fishes.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100273"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000349/pdfft?md5=9dcef2d93de6d800ed80024bae1600f3&pid=1-s2.0-S2772735124000349-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal variation of microeukaryotic biodiversity and biotic condition associated with disinfectants after the COVID-19 lockdown in Wuhan, China","authors":"","doi":"10.1016/j.watbs.2024.100266","DOIUrl":"10.1016/j.watbs.2024.100266","url":null,"abstract":"<div><p>Intensive application of chlorine-based disinfectants driven by the COVID-19 pandemic was suspected to be detrimental to receiving water ecosystems, but with little field evidence. We characterized the occurrences of typical disinfectants and microeukaryotic communities in surface waters associated with three wastewater treatment plants (WWTP)-river systems one year after the lockdown in Wuhan, China. Trihalomethanes (THMs) declined from summer 2020 (0.01–1.82 ​μg/L) to summer 2021 (0.01–0.95 ​μg/L), whereas quaternary ammonium salts (QAs) increased from summer 2020 (0.53–6.35 ​ng/L) to summer 2021 (8.49–191 ​ng/L). Biodiversity monitoring with environmental DNA (eDNA) revealed significant temporal variation in microeukaryotic community composition. The monitored disinfectants were correlated with some eukaryotic communities as demonstrated by redundancy analysis. For example, QAs were positively related to Cryptophyta relative abundance, but negatively related to Rotifera relative abundance. A microeukaryote-based multimetric index indicated ecological impairment near the Han River WWTP outlet in 2020. Our findings indicate the influence of heavily used disinfectants on river microeukaryotic communities, and the usefulness of assessing mid-term ecological risks from disinfectants in the post COVID-19 era.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100266"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000222/pdfft?md5=63bdc043a6d4cc836bb79b061bc7cd04&pid=1-s2.0-S2772735124000222-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140796949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chinese wisdom and modern innovation of aquaculture","authors":"","doi":"10.1016/j.watbs.2024.100271","DOIUrl":"10.1016/j.watbs.2024.100271","url":null,"abstract":"<div><p>Aquaculture originates from ancient Chinese wisdom, and is considered the most efficient food-producing industry. About 70 years ago, New China proposed an industrial approach to fish production and made a policy decision to begin modern aquaculture development. As one of lucky persons since the early 1980s, I have committed my scholarly career to the studies on genetics and breeding biotechnology of polyploid gibel carp (<em>Carassius gibelio</em>). Here, several significant recent innovations, such as the proposition of the amphitriploid concept, the association of ploidy changes with reproduction transition, the finding of a unique ameio-fusiongenesis mode, the establishment of a controllable fertility approach, the creation of intermuscular bone-free mutants, as well as the recreation of desirable goldfish, are introduced and emphasized from an active participant of these innovations. Additionally, some modern innovations and contributions are also highlighted in other aspects of aquaculture including feed development, disease control, facilities and equipment upgrading, as well as paradigm and mode changes. This comprehensive synthesis of ancient Chinese wisdom and modern innovations seeks to provide valuable insights into the field from a historical basis.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100271"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000325/pdfft?md5=0ea102eb650fc1b27c077fb532e7be26&pid=1-s2.0-S2772735124000325-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141030189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SOCS3 acts as a potential negative regulator in the antiviral response of large yellow croaker (Larimichthys crocea) by interacting with STAT1","authors":"","doi":"10.1016/j.watbs.2024.100270","DOIUrl":"10.1016/j.watbs.2024.100270","url":null,"abstract":"<div><p>Suppressors of cytokine signaling (SOCS) proteins are important regulators of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Within the SOCS family, SOCS3 is one of the most potent inhibitors of cytokine signaling. However, there is limited knowledge regarding the function of SOCS3 on regulating type I interferon (IFN) signaling in fish. In this study, the complete open reading frame (ORF) of <em>SOCS3</em> from the large yellow croaker (<em>Larimichthys crocea</em>, <em>LcSOCS3</em>) was cloned and characterized. The ORF of <em>LcSOCS3</em> was 618 nucleotides in length and encoded a protein containing 205 amino acids. <em>Lc</em>SOCS3 had the typical domain architecture of the SOCS family, including an SRC homology 2 (SH2) domain, a SOCS box, an additional kinase inhibition region (KIR), and an extended SH2 subdomain (ESS). Phylogenetic analysis revealed that <em>Lc</em>SOCS3 was clustered with other fish SOCS3s and most closely related to the SOCS3 of <em>Collichthy lucidus</em>. <em>LcSOCS3</em> mRNA was detected in all organs or tissues examined, and its expression was significantly increased in both head kidney and spleen tissues, and primary head kidney leukocytes after poly(I:C) stimulation. Overexpression of <em>Lc</em>SOCS3 significantly promoted Spring viremia of carp virus (SVCV) replication, resulting in a more severe cytopathic effect, increased viral titer, enhanced copy number of the SVCV-G gene, and decreased expression levels of <em>IFN1</em>, <em>IRF7</em>, <em>ISG15</em>, <em>Viperin</em>, <em>PKR</em>, and <em>Mx</em> in epithelioma papulosum cyprinid (EPC) cells. Silencing of <em>LcSOCS3</em> correspondingly up-regulated the expression of <em>IFNi</em>, <em>IFNh</em>, <em>PKR</em>, <em>Viperin</em>, and <em>Mx</em> in large yellow croaker head kidney (LYCK) cells. Additionally, <em>Lc</em>SOCS3 was shown to interact with Signal Transducer and Activator of Transcription 1 (STAT1) which may inhibit STAT1 translocating into the nucleus. This speculation was supported by the increased phosphorylation level of STAT1 in head kidney leukocytes after <em>Lc</em>SOCS3 silencing. These results indicated that <em>Lc</em>SOCS3 functioned as a potential negative regulator of type I IFN signaling in large yellow croaker through its interaction with STAT1.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100270"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000313/pdfft?md5=b52ac5b2108067d0451a152fff75c601&pid=1-s2.0-S2772735124000313-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141051371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extracellular matrix (ECM) pathway involved in skin immune response of Cynoglossus semilaevis upon Vibrio vulnificus infection","authors":"Houfu Liu ,&nbsp;Ge Jin ,&nbsp;Ruoxuan Wang ,&nbsp;Zhengyi Lian ,&nbsp;Xiucai Hu ,&nbsp;Zhang Luo ,&nbsp;Aijun Lv ,&nbsp;Lei Jia ,&nbsp;Xiaodi Shang","doi":"10.1016/j.watbs.2024.100277","DOIUrl":"10.1016/j.watbs.2024.100277","url":null,"abstract":"<div><p>Half-smooth tongue sole (<em>Cynoglossus semilaevis</em>) is regarded as a significant commercial marine fish species in China, and frequent outbreaks of vibriosis has led to substantial economic losses<em>.</em> In this study, we investigated the molecular mechanisms underlying the involvement of the extracellular matrix (ECM) signaling pathway in the skin immune response of <em>C. semilaevis</em> infected with <em>Vibrio vulnificus</em>. The results showed that most differentially expressed proteins (DEPs) were identified through iTRAQ proteome analysis, and ten ECM-related proteins were screened at 12 and 36 ​h post-infection (hpi). Notably, several DEPs associated with ECM including HSPG, FN, COCH, LAMB1, LAMC1, TSPN, COL6A1, AMBP, HX and ITGA6 were tested for their expression at the transcriptional level during <em>V. vulnificus</em> infection using qRT-PCR assay. The analysis of protein-protein interaction (PPI) showed that the integrin ITGA6 exhibited obvious interactions among ECM-related DEPs. Furthermore, the spatio-temporal expression of the <em>Csitga6</em> gene was highest in the skin, gill, muscle, and spleen, but lower in the liver, kidney and intestine. To our knowledge, this is the first report on the involvement of ECM pathway in the skin immune response to <em>V. vulnificus</em> infection, and provides a reference for further study of the ECM mechanism in the mucosal immune response of marine fish.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 3","pages":"Article 100277"},"PeriodicalIF":5.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000386/pdfft?md5=961ca472f3cc76973d6b0b2aa11e2011&pid=1-s2.0-S2772735124000386-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141731968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plastic pollution in marine and freshwater biota","authors":"Gabriella Caruso,&nbsp;Ilaria Corsi,&nbsp;Chenxi Wu,&nbsp;Elisa Bergami,&nbsp;Fabiana Corami,&nbsp;Valter M. Azevedo-Santos","doi":"10.1016/j.watbs.2024.100247","DOIUrl":"10.1016/j.watbs.2024.100247","url":null,"abstract":"<div><p>Plastic pollution is now recognised as a growing concern for both the environment and associated biota. Consequently, a plethora of scientific reports are being produced regarding the occurrence, distribution, and transfer pathways of litter particles. However, there are scientific gaps that need to be filled regarding micro- and nanoplastic impacts on marine and freshwater organisms. This Special Issue (SI) aimed to provide an update on plastic pollution and its consequences on aquatic ecosystems, with a particular focus on biological domains, by adopting a multidisciplinary perspective. Several research articles and reviews were collected, focusing on the origin, fate, and effects of plastics in marine and freshwater environments, along with their interactions with biotic components. We believe this SI will contribute to the development of new studies on plastic pollution and the elaboration of science-based policies at different levels of our modern society.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 2","pages":"Article 100247"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000039/pdfft?md5=5b029b1a99386c66f32466834191d51e&pid=1-s2.0-S2772735124000039-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139632153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The crucial role of fish mucus in regulating progeny inflammation and microbial homeostasis","authors":"Zi-Xuan Wang ,&nbsp;Hao-Yue Xu ,&nbsp;Qiu-Lu He ,&nbsp;Yong-Yao Yu ,&nbsp;Zhen Xu","doi":"10.1016/j.watbs.2024.100248","DOIUrl":"10.1016/j.watbs.2024.100248","url":null,"abstract":"<div><p>Maternal immunity plays a vital role in protecting offspring from pathogen invasion, and it is present in nearly all vertebrates. As the most ancient vertebrates, teleost fish continuously secrete a substantial amount of mucus due to their unique living environment, and often exhibit schooling behavior. Previous studies have highlighted the presence of numerous immune components in the mucus of fish, that plays a crucial role in resisting pathogens. We hypothesize that this represents a distinctive maternal immune response mechanism in fish. In this study, we established a dextran sulfate sodium (DSS)-induced injury model by immersing zebrafish larvae in 0.5% DSS. This elicited robust inflammatory responses and showed DSS-induced alterations in microbial abundance via 16S rRNA sequencing. These changes included the disruption of normal gut structure; an increase in goblet cells; increased expression of inflammatory cytokines; and infiltration of neutrophils and macrophages into the gut, as well as an increase in pathogenic bacteria and a decline in probiotic bacteria. Furthermore, we conducted a mucus protection test by adding adult zebrafish mucus in fish tank water containing 0.5% DSS to test our hypothesis. As suspected, the mucus from adult zebrafish exhibited a protective role in defending zebrafish larvae against DSS-induced enteritis by alleviating excessive inflammatory responses and increasing probiotic abundance. In conclusion, our results confirm a significant role of adult fish mucus in the immune response of teleost fish to DSS-induced inflammation. Collectively, our findings show that the mucus of adult zebrafish may represent a novel form of maternal immunization, playing roles analogous to mammalian milk in immune regulatory functions.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 2","pages":"Article 100248"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000040/pdfft?md5=c96851a9e247a61e9dfc1b3f75bc13cc&pid=1-s2.0-S2772735124000040-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139885824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A droplet digital PCR method (ddPCR) for sensitive detection and quantification of Carassius auratus herpesvirus (CaHV)","authors":"Yun Zhao ,&nbsp;Dan Xu ,&nbsp;Fei Ke ,&nbsp;Yan Zhou ,&nbsp;Mingyou Li ,&nbsp;Lang Gui","doi":"10.1016/j.watbs.2024.100252","DOIUrl":"10.1016/j.watbs.2024.100252","url":null,"abstract":"<div><p><em>Carassius auratus</em> herpesvirus (CaHV) is a pathogen isolated from crucian carp (<em>Carassius auratus</em>) associated with high mortality. A diagnosis method that can detect the virus at an early stage, specifically and accurately, is an urgent requirement for the prevention of CaHV transmission. In the present study, a droplet digital PCR (ddPCR) method based on the tumor necrosis factor receptor (TNFR) gene was established to detect and quantify CaHV DNA with high specificity and no cross-reactions with other aquatic viruses. Skin mucus samples were collected from infected crucian carp from Day 1–8 after infection, and positive amplification was detected on the first day by ddPCR (0.54 copies/μL), whereas the presence of CaHV was not detected by routine PCR until Day 6. Tissue DNA was then collected from the head kidney of 20 fishes which were injected with CaHV and died during the experiment. The five negative samples checked by routine PCR were detected by ddPCR and real-time PCR (qPCR), respectively. The results showed that the positive detection rate of ddPCR (100%) was higher than that of qPCR (40%). The detection limit of the ddPCR was found to be 0.52 copies/μL, which was much lower than the 50.12 copies/μL determined by qPCR. Overall, ddPCR offers a highly promising diagnosis method for the absolute quantification of CaHV in carrier fish and samples from the skin mucus and head kidney with low viral concentrations.</p></div>","PeriodicalId":101277,"journal":{"name":"Water Biology and Security","volume":"3 2","pages":"Article 100252"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772735124000088/pdfft?md5=17ce6affd5dd110e39744a2e3ad82705&pid=1-s2.0-S2772735124000088-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140789895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}