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Power K, Leandri R, Fierro A, Zottola T, De Vico G. Mass mortality of Cornu aspersum in Italian snail farms: A histopathological survey. J Invertebr Pathol 2024; 206:108160. [PMID: 38925365 DOI: 10.1016/j.jip.2024.108160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
The production demand of edible snails in the Mediterranean area is very high and the attention to snail borne diseases is increasing. Following mass mortality events, we have analyzed 240 samples of Cornu aspersum collected from farms across Italy. Anatomopathological examination showed the presence of alterations of the gastro-intestinal apparatus and of the digestive gland, while histopathological examination revealed the presence of Rickettsia-like organisms (RLOs) in 70% (168/240) of cases and Giemsa positive amoebae in the remaining 30% (72/240) of cases. RLOs were localized mainly at the level of the DG, where regressive changes or nodular inflammation was observed. TEM examination of RLOs samples revealed the presence of many rod-shaped electron dense microorganisms. Amoebal infection occurred in the kidney, intestine, lung, the DG and were associated to regressive events or infiltrative/nodular and encapsulation like inflammation. To date it is still unclear if the pathogens detected could represent a risk for humans and animals, therefore further studies are needed to better elucidate this point.
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Affiliation(s)
- Karen Power
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy.
| | - Rebecca Leandri
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Angelo Fierro
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Tiziana Zottola
- Istituto Zooprofilattico Sperimentale Lazio e Toscana M.Aleandri, UOT Lazio Sud, 04100 Latina, Italy
| | - Gionata De Vico
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
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2
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Clinton M, Wyness AJ, Martin SAM, Brierley AS, Ferrier DEK. Association of microbial community structure with gill disease in marine-stage farmed Atlantic salmon (Salmo salar); a yearlong study. BMC Vet Res 2024; 20:340. [PMID: 39090695 PMCID: PMC11293161 DOI: 10.1186/s12917-024-04125-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/10/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND Understanding the relationship between resident microbiota and disease in cultured fish represents an important and emerging area of study. Marine gill disorders in particular are considered an important challenge to Atlantic salmon (Salmo salar) aquaculture, however relatively little is known regarding the role resident gill microbiota might play in providing protection from or potentiating different gill diseases. Here, 16S rRNA sequencing was used to examine the gill microbiome alongside fish health screening in farmed Atlantic salmon. Results were used to explore the relationship between microbial communities and gill disease. RESULTS Microbial community restructuring was observed throughout the sampling period and linked to varied drivers of change, including environmental conditions and severity of gill pathology. Taxa with significantly greater relative abundance on healthier gills included isolates within genus Shewanella, and taxa within family Procabacteriaceae. In contrast, altered abundance of Candidatus Branchiomonas and Rubritalea spp. were associated with damaged gills. Interestingly, more general changes in community richness and diversity were not associated with altered gill health, and thus not apparently deleterious to fish. Gross and histological gill scoring demonstrated seasonal shifts in gill pathology, with increased severity of gill damage in autumn. Specific infectious causes that contributed to observed pathology within the population included the gill disorder amoebic gill disease (AGD), however due to the uncontrolled nature of this study and likely mixed contribution of various causes of gill disease to observed pathology results do not strongly support an association between the microbial community and specific infectious or non-infectious drivers of gill pathology. CONCLUSIONS Results suggest that the microbial community of farmed Atlantic salmon gills undergo continual restructuring in the marine environment, with mixed influences upon this change including environmental, host, and pathogenic factors. A significant association of specific taxa with different gill health states suggests these taxa might make meaningful indicators of gill health. Further research with more frequent sampling and deliberate manipulation of gills would provide important advancement of knowledge in this area. Overall, although much is still to be learnt regarding what constitutes a healthy or maladapted gill microbial community, the results of this study provide clear advancement of the field, providing new insight into the microbial community structure of gills during an annual production cycle of marine-stage farmed Atlantic salmon.
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Affiliation(s)
- Morag Clinton
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK.
- Department of Veterinary Medicine, University of Alaska Fairbanks, Fairbanks, AK, USA.
- Sitka Sound Science Center, Alaska, Sitka, USA.
| | - Adam J Wyness
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK
- Scottish Association for Marine Science, Oban, UK
| | - Samuel A M Martin
- Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK
| | | | - David E K Ferrier
- Scottish Oceans Institute, University of St Andrews, St Andrews, UK.
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3
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Brocca G, Truant A, Peckova H, Lisnerová M, Perolo A, Fioravanti M, Fiala I, Gabai G, Quaglio F, Gustinelli A. Identification of new amoebae strains in rainbow trout (Oncorhynchus mykiss, Walbaum) farms affected by nodular gill disease (NGD) in Northeastern Italy. JOURNAL OF FISH DISEASES 2024; 47:e13933. [PMID: 38400598 DOI: 10.1111/jfd.13933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024]
Abstract
Nodular gill disease (NGD) is an emerging condition associated with amoeba trophozoites in freshwater salmonid farms. However, unambiguous identification of the pathogens still must be achieved. This study aimed to identify the amoeba species involved in periodic NGD outbreaks in two rainbow trout (Oncorhynchus mykiss) farms in Northeastern Italy. During four episodes (February-April 2023), 88 fish were euthanized, and their gills were evaluated by macroscopic, microscopic and histopathological examination. The macroscopic and microscopic severity of the lesions and the degree of amoebae infestation were scored and statistically evaluated. One gill arch from each animal was put on non-nutrient agar (NNA) Petri dishes for amoeba isolation, cultivation and subsequent identification with SSU rDNA sequencing. Histopathology confirmed moderate to severe lesions consistent with NGD and mild to moderate amoeba infestation. The presence of amoebae was significantly correlated with lesion severity. Light microscopy of cultured amoebae strains and SSU rDNA analysis revealed the presence of a previously characterized amoeba Naegleria sp. strain GERK and several new strains: two strains from Hartmannelidae, three vannelid amoebae from the genus Ripella and cercozoan amoeba Rosculus. Despite the uncertainty in NGD etiopathogenesis and amoebae pathogenic role, identifying known and new amoebae leans towards a possible multi-aetiological origin.
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Affiliation(s)
- Ginevra Brocca
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Padua, Italy
- Aquatic Diagnostic Services, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Alessandro Truant
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Padua, Italy
| | - Hana Peckova
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech Republic
| | - Martina Lisnerová
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech Republic
| | - Alberto Perolo
- Servizio Tecnico Commerciale Aquafeed, Gruppo Veronesi, Verona, Veneto Region, Italy
| | - Marialetizia Fioravanti
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | - Ivan Fiala
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech Republic
| | - Gianfranco Gabai
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Padua, Italy
| | - Francesco Quaglio
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Legnaro, Padua, Italy
| | - Andrea Gustinelli
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, Ozzano dell'Emilia, Bologna, Italy
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Rahmati-Holasoo H, Niyyati M, Fatemi M, Mahdavi Abhari F, Shokrpoor S, Nassiri A, Marandi A. Molecular identification, phylogenetic analysis and histopathological study of pathogenic free-living amoebae isolated from discus fish (Symphysodon aequifasciatus) in Iran: 2020-2022. BMC Vet Res 2024; 20:54. [PMID: 38347572 PMCID: PMC10860241 DOI: 10.1186/s12917-024-03902-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/28/2024] [Indexed: 02/15/2024] Open
Abstract
Free-living amoebae (FLA) are capable of inhabiting diverse reservoirs independently, without relying on a host organism, hence their designation as "free-living". The majority of amoebae that infect freshwater or marine fish are amphizoic, or free-living forms that may colonize fish under particular circumstances. Symphysodon aequifasciatus, commonly referred to as the discus, is widely recognized as a popular ornamental fish species. The primary objective of the present study was to determine the presence of pathogenic free-living amoebae (FLA) in samples of discus fish. Fish exhibiting clinical signs, sourced from various fish farms, were transferred to the ornamental fish clinic. The skin, gills, and intestinal mucosa of the fish were collected and subjected to culturing on plates containing a 1% non-nutrient agar medium. The detection of FLA was conducted through morphological, histopathological and molecular methods. The construction of the phylogenetic tree for Acanthamoeba genotypes was achieved using the maximum likelihood approach. The molecular sequence analysis revealed that all cultures that tested positive for FLA were T4 genotype of Acanthamoeba and Acanthamoeba sp. The examination of gill samples using histopathological methods demonstrated the presence of lamellar epithelial hyperplasia, significant fusion of secondary lamellae, and infiltration of inflammatory cells. A multitude of cysts, varying in shape from circular to elliptical, were observed within the gills. The occurrence of interlamellar vesicles and amoeboid organisms could be observed within the epithelial tissue of the gills. In the current study, presence of the Acanthamoeba T4 genotype on the skin and gills of discus fish exhibiting signs of illness in freshwater ornamental fish farms was identified. This observation suggests the potential of a transmission of amoebic infection from ornamental fish to humans, thereby highlighting the need for further investigation into this infection among ornamental fish maintained as pets, as well as individuals who interact with them and their environment.
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Affiliation(s)
- Hooman Rahmati-Holasoo
- Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Maryam Niyyati
- Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Marziye Fatemi
- Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Mahdavi Abhari
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sara Shokrpoor
- Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
| | - Alireza Nassiri
- Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Amin Marandi
- Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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Patchett AL, Rigby ML, Wynne JW. Improved 18S rDNA profiling of parasite communities in salmonid tissues using a host blocking primer. Parasitol Res 2024; 123:124. [PMID: 38319497 PMCID: PMC10847071 DOI: 10.1007/s00436-024-08136-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 01/18/2024] [Indexed: 02/07/2024]
Abstract
Sensitive screening of eukaryotic communities in aquaculture for research and management is limited by the availability of technologies that can detect invading pathogens in an unbiased manner. Amplicon sequencing of 18S ribosomal DNA (rDNA) provides a potential pan-diagnostic test to overcome these biases; however, this technique is limited by a swamping effect of host DNA on low abundance parasite DNA. In this study, we have adapted a host 18S rDNA blocking assay to amplify eukaryotic DNA from salmonid tissue for amplicon sequencing. We demonstrate that effective salmonid 18S rDNA blocking enables sensitive detection of parasite genera in salmonid gill swabs. Furthermore, 18S rDNA amplicon sequencing with host blocking identified enriched pathogen communities in gill swabs from Atlantic salmon suffering from severe clinical gill infections compared to those exhibiting no clinical signs of gill infection. Application of host 18S rDNA blocking in salmonid samples led to improved detection of the amoebic parasite Neoparamoeba perurans, a parasite of significant threat to the Atlantic salmon aquaculture industry. These results reveal host 18S rDNA blocking as an effective strategy to improve the profiling and detection of parasitic communities in aquaculture species. This assay can be readily adapted to any animal species for improved eukaryotic profiling across agricultural and veterinary industries.
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Affiliation(s)
| | - Megan L Rigby
- CSIRO Agriculture and Food, Hobart, Tasmania, 7001, Australia
| | - James W Wynne
- CSIRO Agriculture and Food, Hobart, Tasmania, 7001, Australia
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6
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Vannetti SM, Wynne JW, English C, Huynh C, Knüsel R, de Sales-Ribeiro C, Widmer M, Delalay G, Schmidt-Posthaus H. Amoeba species colonizing the gills of rainbow trout (Oncorhynchus mykiss) in Swiss aquaculture. JOURNAL OF FISH DISEASES 2023; 46:987-999. [PMID: 37294659 DOI: 10.1111/jfd.13819] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/14/2023] [Accepted: 05/17/2023] [Indexed: 06/11/2023]
Abstract
Nodular gill disease (NGD) is an infectious condition characterized by proliferative gill lesions leading to respiratory problems, oxygen deficiency and mortality in fish. Globally, NGD primarily impacts freshwater salmonids in intensive aquaculture systems. In recent years, numerous outbreaks of severe gill disease have affected more than half of the larger rainbow trout (Oncorhynchus mykiss) farms in Switzerland, mainly during spring and early summer. Mortality has reached up to 50% in cases where no treatment was administered. Freshwater amoeba are the presumed aetiologic agent of NGD. The gross gill score (GS) categorising severity of gill pathology is a valuable first-line diagnostic tool aiding fish farmers in identifying and quantifying amoebic gill disease (AGD) in farmed marine salmonids. In this study, the GS was adapted to the NGD outbreak in farmed trout in Switzerland. In addition to scoring disease severity, gill swabs from NGD-affected rainbow trout were sampled and amoeba were cultured from these swabs. Morphologic and molecular methods identified six amoeba strains: Cochliopodium sp., Naegleria sp., Vannella sp., Ripella sp., Saccamoeba sp. and Mycamoeba sp. However, the importance of the different amoeba species for the onset and progression of NGD still has to be evaluated. This paper presents the first description of NGD with associated amoeba infection in farmed rainbow trout in Switzerland.
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Affiliation(s)
- Stefania M Vannetti
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute for Fish and Wildlife Health, University of Bern, Bern, Switzerland
- Fishdoc GmbH, Rain, Switzerland
| | - James W Wynne
- CSIRO Agriculture and Food, Tasmania, Hobart, Australia
| | - Chloe English
- School of Biological Sciences, The University of Queensland, Queensland, Brisbane, Australia
| | | | | | - Carolina de Sales-Ribeiro
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute for Fish and Wildlife Health, University of Bern, Bern, Switzerland
| | - Maro Widmer
- Interfaculty Bioinformatics Unit and SIB Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland
| | - Gary Delalay
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute for Fish and Wildlife Health, University of Bern, Bern, Switzerland
| | - Heike Schmidt-Posthaus
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute for Fish and Wildlife Health, University of Bern, Bern, Switzerland
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7
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Constenla M, Palenzuela O. A New Parasitic Archamoeba Causing Systemic Granulomatous Disease in Goldfish Extends the Diversity of Pathogenic Endolimax spp. Animals (Basel) 2023; 13:ani13050935. [PMID: 36899792 PMCID: PMC10000153 DOI: 10.3390/ani13050935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/01/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Endolimax is a genus of intestinal amoebae which stands among the least known human protists. Previous studies on amoebic systemic granulomatosis of a marine fish (Solea senegalensis) resulted in the unexpected characterization of a new organism which was related to Endolimax and named E. piscium. The existence of multiple reports of systemic granulomatosis caused presumptively by unidentified amoebae in goldfish lead us to investigate the organism involved in goldfish disease. Analysed goldfish presented small whitish nodules in the kidney, which correspond to chronic granulomatous inflammatory reactions with a ring-layer of amoebae in the periphery. Amoebae were amitochondriate and were located in a parasitophorous vacuole within macrophages, as previous studies on this condition in goldfish and other freshwater fish pointed out. SSU rDNA characterization confirmed a new Endolimax lineage which appears closely related to E. piscium, but the molecular evidence, distinct pathological features and lack of ecological overlapping between the hosts support their assignment to a new species, E. carassius. The results support the existence of a considerable unexplored diversity of Endolimax spp. among fish, and their proper characterization can contribute to an understanding of Archamoebae evolution and pathogenic potential.
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Affiliation(s)
- Maria Constenla
- Departament de Biologia Animal, de Biologia Vegetal i Ecologia and Servei de Diagnostic Patologic en Peixos, Universitat Autonoma de Barcelona (UAB), 08193 Barcelona, Spain
| | - Oswaldo Palenzuela
- Instituto de Acuicultura Torre de la Sal (IATS, CSIC), 12595 Ribera de Cabanes, Spain
- Correspondence:
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Ríos-Castro R, Romero A, Aranguren R, Pallavicini A, Banchi E, Novoa B, Figueras A. High-Throughput Sequencing of Environmental DNA as a Tool for Monitoring Eukaryotic Communities and Potential Pathogens in a Coastal Upwelling Ecosystem. Front Vet Sci 2021; 8:765606. [PMID: 34805343 PMCID: PMC8595318 DOI: 10.3389/fvets.2021.765606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/08/2021] [Indexed: 12/04/2022] Open
Abstract
The marine environment includes diverse microeukaryotic organisms that play important functional roles in the ecosystem. With molecular approaches, eukaryotic taxonomy has been improved, complementing classical analysis. In this study, DNA metabarcoding was performed to describe putative pathogenic eukaryotic microorganisms in sediment and marine water fractions collected in Galicia (NW Spain) from 2016 to 2018. The composition of eukaryotic communities was distinct between sediment and water fractions. Protists were the most diverse group, with the clade TSAR (Stramenopiles, Alveolata, Rhizaria, and Telonemida) as the primary representative organisms in the environment. Harmful algae and invasive species were frequently detected. Potential pathogens, invasive pathogenic organisms as well as the causative agents of harmful phytoplanktonic blooms were identified in this marine ecosystem. Most of the identified pathogens have a crucial impact on the aquacultural sector or affect to relevant species in the marine ecosystem, such as diatoms. Moreover, pathogens with medical and veterinary importance worldwide were also found, as well as pathogens that affect diatoms. The evaluation of the health of a marine ecosystem that directly affects the aquacultural sector with a zoonotic concern was performed with the metabarcoding assay.
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Affiliation(s)
- Raquel Ríos-Castro
- Inmunology and Genomics, Marine Research Institute (IIM-CSIC), Vigo, Spain
| | - Alejandro Romero
- Inmunology and Genomics, Marine Research Institute (IIM-CSIC), Vigo, Spain
| | - Raquel Aranguren
- Inmunology and Genomics, Marine Research Institute (IIM-CSIC), Vigo, Spain
| | - Alberto Pallavicini
- Department of Life Sciences, University of Trieste, Trieste, Italy
- Division of Oceanography, National Institute of Oceanography and Applied Geophysics, Trieste, Italy
| | - Elisa Banchi
- Department of Life Sciences, University of Trieste, Trieste, Italy
- Division of Oceanography, National Institute of Oceanography and Applied Geophysics, Trieste, Italy
| | - Beatriz Novoa
- Inmunology and Genomics, Marine Research Institute (IIM-CSIC), Vigo, Spain
| | - Antonio Figueras
- Inmunology and Genomics, Marine Research Institute (IIM-CSIC), Vigo, Spain
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