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Strand DA, Jinnerot T, Aspán A, Viljamaa-Dirks S, Heinikainen S, Rolén E, Vrålstad T. Molecular detection of Aphanomyces astaci - An improved species specific qPCR assay. J Invertebr Pathol 2023; 201:108008. [PMID: 37863282 DOI: 10.1016/j.jip.2023.108008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/12/2023] [Accepted: 10/17/2023] [Indexed: 10/22/2023]
Abstract
The parasitic oomycete Aphanomyces astaci is the causative agent of crayfish plague, a devastating disease for European freshwater crayfish. Species specific quantitative real-time PCR (qPCR) can offer rapid detection of the pathogen. However, the well established A. astaci qPCR assay recommended by the World Organization for Animal Health (WOAH) amplifies the recently described Aphanomyces fennicus. Consequently, false-positive results may occur. This calls for the improvement of the established species specific A. astaci qPCR assay in order to avoid amplifying A. fennicus while screening for A. astaci. We developed an improved species specific A. astaci qPCR assay and validated the assay across three laboratories, using established procedures including different qPCR master mixes for each respective laboratory. Genomic DNA from A. astaci, A. fennicus and closely related Aphanomyces spp. was analysed and compared with both the improved and established assay. Additionally, DNA from crayfish tissue and environmental samples were analysed with both assays. The improved assay showed similar sensitivity with the established assay for all sample types, while proving highly specific for A. astaci avoiding amplification of A. fennicus and the other tested Aphanomyces spp. Environmental DNA (eDNA) samples collected at River Lierelva in Norway amplified with the established assay, but not with the improved assay indicating false positive. We were able to sequence a 530 bp fragment of the ITS region from these eDNA samples and the consensus sequence showed 99.9-100 % pairwise identity with A. fennicus and 97.2-98 % pairwise identity with A. astaci, suggesting that the occurrence of A. fennicus is not limited to Finland, where it was first discovered.
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Affiliation(s)
| | | | - Anna Aspán
- National Veterinary Institute, Uppsala, Sweden
| | | | | | - Elin Rolén
- Norwegian Veterinary Institute, Oslo, Norway
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2
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Grbin D, Geček S, Miljanović A, Pavić D, Hudina S, Žučko J, Rieder J, Pisano SRR, Adrian-Kalchhauser I, Bielen A. Comparison of exoskeleton microbial communities of co-occurring native and invasive crayfish species. J Invertebr Pathol 2023; 201:107996. [PMID: 37783231 DOI: 10.1016/j.jip.2023.107996] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/04/2023]
Abstract
Host-associated microbial communities are an important determinant of individual fitness and have recently been highlighted as one of the factors influencing the success of invasive species. Invasive hosts introduce their microbes into the new environment, and then both the host and its associated microbes enter into a series of interactions with the native macroscopic and microscopic biota. As these processes are largely unexplored, we aimed to compare the exoskeletal microbial communities of co-occurring and phylogenetically related crayfish: the native narrow-clawed crayfish Pontastacus leptodactylus and the invasive signal crayfish Pacifastacus leniusculus from the recently invaded Korana River, Croatia. The results of high-throughput 16S rRNA sequencing showed that the exoskeletal microbiome of both species is very diverse, significantly influenced by the local environment and dominated by low abundance bacterial families from the phylum Proteobacteria. Furthermore, the exoskeletal microbiomes of the crayfish species differed significantly in the composition and abundance of Amplicon Sequence Variants (ASVs), suggesting that they are to some extent shaped by species-specific intrinsic factors, despite sharing a common habitat. However, over 95% of the bacterial genera associated with the exoskeleton were detected in the exoskeleton samples of both native and invasive crayfish. We paid particular attention to two known crayfish pathogens, Aphanomyces astaci and Saprolegnia parasitica, and find that both species carry low amounts of both pathogens. On the side, we find that a non-standard ddPCR protocol outperforms standard qPCR test for A. astaci under low concentration conditions. Taken together, our results indicate the possibility of bidirectional mixing and homogenisation of exoskeleton microbiome. As such, they can serve as a baseline in future detangling of the processes that act together to shape the microbiomes of co-occuring native and invasive congeners during biological invasions.
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Affiliation(s)
- Dorotea Grbin
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia; Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
| | - Sunčana Geček
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
| | - Anđela Miljanović
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
| | - Dora Pavić
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
| | - Sandra Hudina
- Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia.
| | - Jurica Žučko
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
| | - Jessica Rieder
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland; Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland; Swiss Institute of Bioinformatics, Quartier Sorge - Batiment Amphipole, 1015 Lausanne, Switzerland.
| | - Simone R R Pisano
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland.
| | - Irene Adrian-Kalchhauser
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland.
| | - Ana Bielen
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
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Jussila J, Edsman L, Maguire I, Diéguez-Uribeondo J, Theissinger K. Money Kills Native Ecosystems: European Crayfish as an Example. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.648495] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Native European crayfish conservation was triggered by invasion of crayfish plague disease agent, Aphanomyces astaci, starting 1860s in Northern Italy. Resulting crayfish plague epidemics quickly spread over Continental Europe, then to Finland, Sweden and finally, after running amok around Europe, A. astaci was discovered also in Iberian Peninsula, Norway, Ireland, and United Kingdom in 1970s and 1980s. By that time significant proportion of native crayfish stocks had been lost, and while crayfish plague epidemics were still recorded, also industrialization and waterways construction were causing damage to remaining native crayfish stocks. While alien crayfish introductions, at least Faxonius limosus, already gave rise to first wave of crayfish plague epidemics in late 19th century, later in 1960s it was decided that introductions of alien Pacifastacus leniusculus should be initiated to replace native European crayfish populations. Decisions were based on presumed advantages for fishery, suitable habitat requirements and supposed immunity against A. astaci. Furthermore, conservation of native European crayfish species was sidelined and focus shifted toward alien crayfish stocking routine and consumption. Alien crayfish species introductions resulted in repeated waves of crayfish plague epidemics among remaining native crayfish stocks. It was soon discovered that alien crayfish of North American origin were, as suspected, permanent reservoirs for A. astaci, that some of those alien species were losing their resistance against selected strains of A. astaci and struggled in European aquatic ecosystems. In this article, we introduce numerous motives behind grand mistake of introducing alien crayfish species to Europe and then promoting their stocks instead of focusing on conservation of native crayfish species. We outline how false economical, biological and ecologic assumptions were used to justify a hasty introduction of alien crayfish, which has further devastated native crayfish and also permanently changed European aquatic ecosystems, both with disastrous consequences. Lesson to be learnt is that science-based warnings about alien species damage to native ecosystems and native crayfish must be taken with utmost caution. Protection of native European crayfish should be core issue, not commercial activities. Finally, we summarize main threats and actions needed to protect remaining native freshwater crayfish fauna in Europe.
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Crayfish plague in Czechia: Outbreaks from novel sources and testing for chronic infections. J Invertebr Pathol 2020; 173:107390. [PMID: 32353366 DOI: 10.1016/j.jip.2020.107390] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/24/2020] [Accepted: 04/26/2020] [Indexed: 11/23/2022]
Abstract
The crayfish plague pathogen Aphanomyces astaci, which is among the most studied pathogens of aquatic invertebrates, co-evolved with North American crayfish species but threatens crayfish on other continents. The pathogen causes mass mortalities, particularly in Europe. In this study we document 12 crayfish plague outbreaks that occurred from 2014 to 2019 in Czechia and, by using available molecular techniques (microsatellite and mtDNA markers), we reveal the A. astaci genotypes involved. Our results provide the first evidence of strains from genotype group D, originally associated with the host Procambarus clarkii, causing Astacus astacus and Austropotamobius torrentium mass mortalities in Czechia. Moreover, mtDNA sequencing confirmed two distinct haplotypes of the D haplogroup, indicating two independent sources of infection, presumably originating from ornamental crayfish in the pet trade or spreading from crayfish established in neighbouring countries. Genotype group A was recorded in two As. astacus mortalities, and genotype group E, associated with Faxonius limosus, in two Au. torrentium and three As. astacus mortalities. Microsatellite genotyping also reidentified the unusual genotype SSR-Up in two As. astacus outbreaks, ten years after its first documented occurrence. In addition, we tested healthy-appearing indigenous crayfish from 25 localities for potential chronic infections. No traces of A. astaci DNA were detected; chronic infections in European crayfish species thus do not seem a pervasive phenomenon in Czechia. However, their role as A. astaci latent reservoirs, especially in Pontastacus leptodactylus populations introduced to the country since the late 19th century, cannot be excluded.
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Pavić D, Čanković M, Petrić I, Makkonen J, Hudina S, Maguire I, Vladušić T, Šver L, Hrašćan R, Orlić K, Dragičević P, Bielen A. Non-destructive method for detecting Aphanomyces astaci, the causative agent of crayfish plague, on the individual level. J Invertebr Pathol 2020; 169:107274. [DOI: 10.1016/j.jip.2019.107274] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 10/27/2019] [Accepted: 10/30/2019] [Indexed: 01/21/2023]
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Viljamaa-Dirks S, Heinikainen S. A tentative new species Aphanomyces fennicus sp. nov. interferes with molecular diagnostic methods for crayfish plague. JOURNAL OF FISH DISEASES 2019; 42:413-422. [PMID: 30644112 DOI: 10.1111/jfd.12955] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 12/07/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
Several isolates of an unknown oomycete resembling the genus Aphanomyces were obtained into laboratory culture from samples of noble crayfish (Astacus astacus) in 2016-2017. The crayfish were kept in cages in connection with a study on an eventually persistent crayfish plague infection in a small Finnish lake, following an acute episode of the disease in 2010. Despite the close resemblance of the isolates to the causative agent of crayfish plague, Aphanomyces astaci, and the positive results obtained in OIE recommended A. astaci-specific ITS-based conventional PCR and qPCR molecular assays, the isolates can be distinguished from A. astaci by morphological features concerning hyphal structure and chlamydospore formation, as well as using the randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) method, microsatellite-based genotyping, the pathogenicity test and phylogenetic analysis based on ITS sequencing. The name Aphanomyces fennicus sp. novum is proposed for this close relative of A. astaci. The detection of this tentative novel species giving false-positive results in existing diagnostic assays for the crayfish plague highlights the importance of careful interpretation of the results from molecular methods, especially concerning crayfish with low-level infections, excluding the possibility to verify the results from clinical or sequencing data.
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Affiliation(s)
- Satu Viljamaa-Dirks
- Veterinary Bacteriology and Pathology Research Unit, OIE Reference Laboratory for Crayfish Plague, Finnish Food Safety Authority Evira, Kuopio, Finland
| | - Sirpa Heinikainen
- Veterinary Bacteriology and Pathology Research Unit, OIE Reference Laboratory for Crayfish Plague, Finnish Food Safety Authority Evira, Kuopio, Finland
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7
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Caprioli R, Mrugała A, Di Domenico M, Curini V, Giansante C, Cammà C, Petrusek A. Aphanomyces astaci genotypes involved in recent crayfish plague outbreaks in central Italy. DISEASES OF AQUATIC ORGANISMS 2018; 130:209-219. [PMID: 30259873 DOI: 10.3354/dao03275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The oomycete Aphanomyces astaci is the causative agent of crayfish plague in native European freshwater crayfish. Molecular analyses showed that several distinct genotype groups of this pathogen, apparently associated with different original host taxa, are present in Europe. Tracking their distribution may contribute to understanding the introduction pathways of A. astaci. We used microsatellite markers to genotype the pathogen strains involved in 7 mass mortalities of the endangered indigenous crayfish Austropotamobius pallipes that occurred between 2009 and 2016 in the Abruzzi and Molise regions, central Italy. Three A. astaci genotype groups (A, B, and D, with the latter represented by 2 distinct multilocus genotypes) were identified, suggesting the existence of multiple infection sources even in a relatively small area. Most crayfish plague episodes were due to genotype groups associated with the North American host species Pacifastacus leniusculus and Procambarus clarkii, although these crayfish are not widespread in the study area. A. astaci genotype group A was detected not only in crayfish plague outbreaks but also in apparently healthy Astacus leptodactylus imported for human consumption from Armenia and kept alive in an aquaculture facility. Imports of chronically infected A. leptodactylus from Armenia, Turkey, and possibly Eastern Europe are an underestimated introduction pathway for A. astaci. Although we cannot exclude the presence of latently infected native populations of A. pallipes in the region, A. astaci infections in legally imported crayfish species considered vulnerable to crayfish plague may represent further reservoirs of A. astaci; this should be reflected in the policies regulating the trade of live crayfish.
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Affiliation(s)
- Riccardo Caprioli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale', 64100 Teramo, Italy
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Panteleit J, Keller NS, Diéguez-Uribeondo J, Makkonen J, Martín-Torrijos L, Patrulea V, Pîrvu M, Preda C, Schrimpf A, Pârvulescu L. Hidden sites in the distribution of the crayfish plague pathogen Aphanomyces astaci in Eastern Europe: Relicts of genetic groups from older outbreaks? J Invertebr Pathol 2018; 157:117-124. [PMID: 29787742 DOI: 10.1016/j.jip.2018.05.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 05/10/2018] [Accepted: 05/18/2018] [Indexed: 11/18/2022]
Abstract
The crayfish plague agent Aphanomyces astaci is one of the world's most threatening invasive species. Originally from North America, the pathogen is being imported alongside American crayfish species, which are used for various purposes. In this study, we investigated the marginal, currently known distribution area of the pathogen in Eastern Europe by sampling narrow-clawed crayfish (Astacus leptodactylus) and spiny-cheek crayfish (Orconectes limosus) populations. In addition, using specific real-time PCR, we tested several marine decapod species, which also occur in brackish waters of the Danube at the West coast of the Black Sea and the Dniester River basin. By sequencing the nuclear chitinase gene, mitochondrial rnnS/rnnL DNA and by genotyping using microsatellite markers, we identified the A. astaci haplogroups of highly infected specimens. The A. astaci DNA was detected in 9% of the investigated A. leptodactylus samples, both in invaded and non-invaded sectors, and in 8% of the studied O. limosus samples. None of the marine decapods tested positive for A. astaci. The results revealed that narrow-clawed crayfish from the Dniester River carried the A. astaci B-haplogroup, while A. astaci from the Danube Delta belonged to the A- and B-haplogroups. In the invaded sector of the Danube, we also identified the A-haplogroup. Microsatellite analysis revealed a genotype identical to the genotype Up. It might be that some of the detected A. astaci haplogroups are relics from older outbreaks in the late 19th century, which may have persisted as a chronic infection for several decades in crayfish populations.
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Affiliation(s)
- Jörn Panteleit
- University of Koblenz-Landau, Institute for Environmental Sciences, 76829 Landau, Germany.
| | - Nina Sophie Keller
- University of Koblenz-Landau, Institute for Environmental Sciences, 76829 Landau, Germany.
| | | | - Jenny Makkonen
- Department of Environmental and Biological Sciences, University of Eastern Finland, 70210 Kuopio, Finland.
| | | | - Viorica Patrulea
- University of Geneva, University of Lausanne, School of Pharmaceutical Sciences, 1211 Geneva, Switzerland.
| | - Mălina Pîrvu
- West University of Timisoara, Faculty of Chemistry, Biology, Geography, Department of Biology-Chemistry, 300115 Timisoara, Romania.
| | - Cristina Preda
- Ovidius University of Constanta, Faculty of Natural and Agricultural Sciences, 900470 Constanta, Romania.
| | - Anne Schrimpf
- University of Koblenz-Landau, Institute for Environmental Sciences, 76829 Landau, Germany.
| | - Lucian Pârvulescu
- West University of Timisoara, Faculty of Chemistry, Biology, Geography, Department of Biology-Chemistry, 300115 Timisoara, Romania.
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Jussila J, Vrezec A, Jaklič T, Kukkonen H, Makkonen J, Kokko H. Aphanomyces astaci isolate from latently infected stone crayfish (Austropotamobius torrentium) population is virulent. J Invertebr Pathol 2017; 149:15-20. [DOI: 10.1016/j.jip.2017.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/11/2017] [Accepted: 07/13/2017] [Indexed: 11/28/2022]
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Svoboda J, Mrugała A, Kozubíková-Balcarová E, Petrusek A. Hosts and transmission of the crayfish plague pathogen Aphanomyces astaci: a review. JOURNAL OF FISH DISEASES 2017; 40:127-140. [PMID: 27111501 DOI: 10.1111/jfd.12472] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 06/05/2023]
Abstract
The crayfish plague pathogen, Aphanomyces astaci Schikora, has become one of the most well-studied pathogens of invertebrates. Since its introduction to Europe in the mid-19th century, it has caused mass crayfish mortalities, resulting in drastic declines of local populations. In contrast, North American crayfish usually serve as latent carriers, although they may also be negatively affected by A. astaci infections under some circumstances. Recent research benefiting from molecular tools has improved our knowledge about various aspects of A. astaci biology. In this review, we summarize these advances, particularly with respect to the host range and transmission. We highlight several aspects that have recently received particular attention, in particular newly confirmed or suspected A. astaci hosts, latent A. astaci infections in populations of European crayfish, and the relationship between A. astaci genotype groups and host taxa.
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Affiliation(s)
- J Svoboda
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
| | - A Mrugała
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
| | - E Kozubíková-Balcarová
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
| | - A Petrusek
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
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11
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Effects of Different Treatments on the Quality and Safety of Crayfish (Astacus leptodactylus). J FOOD QUALITY 2017. [DOI: 10.1155/2017/2904706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study was aimed to determine the effect of different killing methods (frozen, mechanical, and traditional) on the quality, safety, and shelf life of crayfish that are aerobically stored under chilled conditions. The population of microorganisms (i.e., total mesophilic aerobic bacteria (TMAB), total psychrophilic aerobic bacteria (TPAB), and Enterobacteriaceae) was increased regarding to storage time (p<0.05). Significant differences (p>0.05) were not observed in pH values during storage time. In contrast to this, total volatile basic nitrogen (TVB-N) values of the samples were increased significantly (p<0.05) during storage. Sensory results were highly correlated with the microbiological counts (r=-0.92 for TMAB × odour; r=-0.95 for TPAB × odour; and r=-0.96 for Enterobacteriaceae × odour). Fifteen different fatty acids and 5 biogenic amines were detected for the determination of initial quality and safety of crayfish. In conclusion, frozen killed samples were found to be effective and laborsaving method as an alternative to traditional killing methods by maintaining the quality and safety of crayfish at the beginning and during storage under chilled conditions.
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Ludányi M, Peeters EE, Kiss B, Roessink I. Distribution of crayfish species in Hungarian waters. Glob Ecol Conserv 2016. [DOI: 10.1016/j.gecco.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Maguire I, Jelić M, Klobučar G, Delpy M, Delaunay C, Grandjean F. Prevalence of the pathogen Aphanomyces astaci in freshwater crayfish populations in Croatia. DISEASES OF AQUATIC ORGANISMS 2016; 118:45-53. [PMID: 26865234 DOI: 10.3354/dao02955] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Oomycete Aphanomyces astaci is an obligate crayfish parasite that co-evolved with American crayfish species, and they therefore generally live in a balanced relationship. On the contrary, European native crayfish are highly susceptible to A. astaci, and infestation with it causes development of the lethal disease termed crayfish plague. Until now, 5 A. astaci strains have been described from the freshwater crayfish present in Europe. In this study we aimed to investigate the occurrence of the pathogen A. astaci in Croatian native and non-native crayfish populations, as well as to genotype established strains using microsatellite markers and obtain information on the pathogen's epidemiology. Our results showed that the pathogen is widespread in both native and non-native crayfish populations. Agent level, when positive, in non-native crayfish was generally low; in native species it was higher. Genotyping from microsatellites proved the presence of the B (Ps) strain in non-native species (Pacifastacus leniusculus), while the A (As) strain was detected from viable native species (Astacus astacus and Austropotamobius torrentium) that are distributed in areas lacking non-native crayfish. The genotype from A. torrentium differed from a typical A (As) by 1 allele. Strain B (Ps) was identified in native Astacus leptodactylus from the population that co-occurs with P. leniuscuslus. Interestingly, in 1 A. leptodactylus population both A (As) and B (Ps) strains were present.
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Affiliation(s)
- Ivana Maguire
- University of Zagreb, Faculty of Science, Department of Biology, Rooseveltov trg 6, 10000 Zagreb, Croatia
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14
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Becking T, Mrugała A, Delaunay C, Svoboda J, Raimond M, Viljamaa-Dirks S, Petrusek A, Grandjean F, Braquart-Varnier C. Effect of experimental exposure to differently virulent Aphanomyces astaci strains on the immune response of the noble crayfish Astacus astacus. J Invertebr Pathol 2015; 132:115-124. [PMID: 26410255 DOI: 10.1016/j.jip.2015.08.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 10/23/2022]
Abstract
European crayfish are sensitive to the crayfish plague pathogen, Aphanomyces astaci, carried by North American crayfish species due to their less effective immune defence mechanisms against this disease. During a controlled infection experiment with a susceptible crayfish species Astacus astacus using three A. astaci strains (representing genotype groups A, B, and E), we investigated variation in their virulence and in crayfish immune defence indicators (haemocyte density, phenoloxidase activity, and production of reactive oxygen species). Experimental crayfish were exposed to two dosages of A. astaci spores (1 and 10 spores mL(-1)). The intensity and timing of the immune response differed between the strains as well as between the spore concentrations. Stronger and faster change in each immune parameter was observed in crayfish infected with two more virulent strains, indicating a relationship between crayfish immune response and A. astaci virulence. Similarly, the immune response was stronger and was observed earlier for the higher spore concentration. For the first time, the virulence of a strain of the genotype group E (isolated from Orconectes limosus) was experimentally tested. Total mortality was reached after 10 days for the two higher spore dosages (10 and 100 spores mL(-1)), and after 16 days for the lowest (1 spore mL(-1)), revealing equally high and rapid mortality as caused by the genotype group B (from Pacifastacus leniusculus). No mortality occurred after infection with genotype group A during 60 days of the experimental trial.
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Affiliation(s)
- Thomas Becking
- Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France
| | - Agata Mrugała
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2 CZ-12844, Czech Republic
| | - Carine Delaunay
- Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France
| | - Jiří Svoboda
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2 CZ-12844, Czech Republic
| | - Maryline Raimond
- Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France
| | - Satu Viljamaa-Dirks
- Finnish Food Safety Authority Evira, OIE Reference Laboratory for Crayfish Plague, 70701 Kuopio, Finland
| | - Adam Petrusek
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2 CZ-12844, Czech Republic
| | - Frédéric Grandjean
- Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France.
| | - Christine Braquart-Varnier
- Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France
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Pârvulescu L, Pîrvu M, Moroşan LG, Zaharia C. Plasticity in fecundity highlights the females' importance in the spiny-cheek crayfish invasion mechanism. ZOOLOGY 2015; 118:424-32. [PMID: 26358988 DOI: 10.1016/j.zool.2015.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 07/19/2015] [Accepted: 08/26/2015] [Indexed: 11/30/2022]
Abstract
Invasion is one of the most consequential phenomena affecting the distribution of native species. Few in number of species, European crayfish are losing the competition with introduced North American crayfish. The spiny-cheek crayfish, Orconectes limosus, is an outstanding example, successfully competing against the native narrow-clawed crayfish, Astacus leptodactylus. For four years, we collected data regarding crayfish occurrences, their relative abundance, and the structure of populations in the ongoing colonisation process of O. limosus in the lower Danube. The mature females of both invasive and indigenous crayfish species were analysed with respect to biometry and production of oocytes in relation to the dynamics of invasion. The interspecific comparisons showed no significant differences regarding body size, with an average of approximately 102 mm total length and 31 g wet weight for both species. However, the fecundity of the indigenous species was found to be constant throughout the investigated area, whereas the number of eggs produced by the invasive females was significantly increased at the active front of the invasion. The maximum number of ovarian eggs found was 887 and 1156 in the indigenous species and the invasive species, respectively. We propose the scenario that the invasive species, which carries the deadly crayfish plague, creates an ecological advantage by reducing the populations of indigenous crayfish. Subsequently, the invasive females opportunistically use the available resources to enhance their fecundity, resulting in the acute growth of populations. However, the long-term competitiveness and colonisation success of O. limosus still remain in question.
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Affiliation(s)
- Lucian Pârvulescu
- Department of Biology-Chemistry, Faculty of Chemistry, Biology, Geography, West University of Timisoara, 16A Pestalozzi St, 300115 Timisoara, Romania.
| | - Mălina Pîrvu
- Department of Biology-Chemistry, Faculty of Chemistry, Biology, Geography, West University of Timisoara, 16A Pestalozzi St, 300115 Timisoara, Romania
| | - Loredana-Giorgiana Moroşan
- Department of Biology-Chemistry, Faculty of Chemistry, Biology, Geography, West University of Timisoara, 16A Pestalozzi St, 300115 Timisoara, Romania
| | - Claudia Zaharia
- Department of Mathematics, Faculty of Mathematics and Computer Science, West University of Timisoara, V. Parvan Blvd., 300223 Timisoara, Romania
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16
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Evolution of resistance by a native competitor can lead to invasion collapse in disease-mediated invasions. Biol Invasions 2015. [DOI: 10.1007/s10530-015-0916-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Reprint of: The diversity of oomycetes on crayfish: Morphological vs. molecular identification of cultures obtained while isolating the crayfish plague pathogen. Fungal Biol 2014; 118:601-11. [PMID: 25088074 DOI: 10.1016/j.funbio.2014.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 11/20/2022]
Abstract
Numerous oomycetes colonise the crayfish cuticle, the best known being the crayfish plague pathogen Aphanomyces astaci. Although other oomycetes associated with crayfish complicate the isolation and molecular detection of A. astaci, their diversity is little known. To improve this knowledge, we analysed 95 oomycete isolates obtained during attempts to isolate A. astaci from crayfish presumably infected by this pathogen. We characterized the isolates morphologically and by sequencing of the nuclear internal transcribed spacer (ITS) region. We identified 13 taxa by molecular analysis. Ten of them were assigned to five genera; the remaining three were affiliated with the order Saprolegniales but could not be reliably assigned to any genus. Morphological identification to species level was only possible for 15 % of isolates; all corresponded to Saprolegnia ferax, which was confirmed by ITS sequencing. The most frequently isolated species were S. ferax and Saprolegnia australis. Only seven isolates of A. astaci were obtained, all from one disease outbreak. We show that oomycete cultures obtained as by-products of parasite isolation are valuable for oomycete diversity studies, but morphological identification may uncover only a fraction of their diversity. Further, we show that crayfish may be frequently associated with potentially serious parasites of other organisms.
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Gruber C, Kortet R, Vainikka A, Hyvärinen P, Rantala MJ, Pikkarainen A, Jussila J, Makkonen J, Kokko H, Hirvonen H. Variation in Resistance to the Invasive Crayfish Plague and Immune Defence in the Native Noble Crayfish. ANN ZOOL FENN 2014. [DOI: 10.5735/086.051.0403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Grandjean F, Vrålstad T, Diéguez-Uribeondo J, Jelić M, Mangombi J, Delaunay C, Filipová L, Rezinciuc S, Kozubíková-Balcarová E, Guyonnet D, Viljamaa-Dirks S, Petrusek A. Microsatellite markers for direct genotyping of the crayfish plague pathogen Aphanomyces astaci (Oomycetes) from infected host tissues. Vet Microbiol 2014; 170:317-24. [DOI: 10.1016/j.vetmic.2014.02.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/10/2014] [Accepted: 02/15/2014] [Indexed: 11/26/2022]
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20
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Kozubíková-Balcarová E, Beran L, Ďuriš Z, Fischer D, Horká I, Svobodová J, Petrusek A. Status and recovery of indigenous crayfish populations after recent crayfish plague outbreaks in the Czech Republic. ETHOL ECOL EVOL 2014. [DOI: 10.1080/03949370.2014.897652] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Huys R, Oidtmann B, Pond M, Goodman H, Clark P. Invasive crayfish and their symbionts in the Greater London area: new data and the fate of Astacus leptodactylusin the Serpentine and Long Water Lakes. ETHOL ECOL EVOL 2014. [DOI: 10.1080/03949370.2014.903433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Makkonen J, Kokko H, Vainikka A, Kortet R, Jussila J. Dose-dependent mortality of the noble crayfish (Astacus astacus) to different strains of the crayfish plague (Aphanomyces astaci). J Invertebr Pathol 2014; 115:86-91. [DOI: 10.1016/j.jip.2013.10.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/15/2013] [Accepted: 10/22/2013] [Indexed: 11/16/2022]
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23
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The diversity of oomycetes on crayfish: Morphological vs. molecular identification of cultures obtained while isolating the crayfish plague pathogen. Fungal Biol 2013; 117:682-91. [DOI: 10.1016/j.funbio.2013.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022]
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24
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Filipová L, Petrusek A, Matasová K, Delaunay C, Grandjean F. Prevalence of the crayfish plague pathogen Aphanomyces astaci in populations of the signal crayfish Pacifastacus leniusculus in France: evaluating the threat to native crayfish. PLoS One 2013; 8:e70157. [PMID: 23894606 PMCID: PMC3720925 DOI: 10.1371/journal.pone.0070157] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 06/20/2013] [Indexed: 11/24/2022] Open
Abstract
Aphanomyces astaci, the crayfish plague pathogen, first appeared in Europe in the mid-19th century and is still responsible for mass mortalities of native European crayfish. The spread of this parasite across the continent is especially facilitated by invasive North American crayfish species that serve as its reservoir. In France, multiple cases of native crayfish mortalities have been suggested to be connected with the presence of the signal crayfish Pacifastacus leniusculus, which is highly abundant in the country. It shares similar habitats as the native white-clawed crayfish Austropotamobius pallipes and, when infected, the signal crayfish might therefore easily transmit the pathogen to the native species. We investigated the prevalence of A. astaci in French signal crayfish populations to evaluate the danger they represent to local populations of native crayfish. Over 500 individuals of Pacifastacus leniusculus from 45 French populations were analysed, plus several additional individuals of other non-indigenous crayfish species Orconectes limosus, O. immunis and Procambarus clarkii. Altogether, 20% of analysed signal crayfish tested positive for Aphanomyces astaci, and the pathogen was detected in more than half of the studied populations. Local prevalence varied significantly, ranging from 0% up to 80%, but wide confidence intervals suggest that the number of populations infected by A. astaci may be even higher than our results show. Analysis of several individuals of other introduced species revealed infections among two of these, O. immunis and P. clarkii. Our results confirm that the widespread signal crayfish serves as a key reservoir of Aphanomyces astaci in France and therefore represents a serious danger to native crayfish species, especially the white-clawed crayfish. The prevalence in other non-indigenous crayfish should also be investigated as they likely contribute to pathogen transmission in the country.
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Affiliation(s)
- Lenka Filipová
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Laboratoire Ecologie et Biologie des Interactions, Equipe « Ecologie, Evolution, Symbiose », UMR 7267 CNRS, Université de Poitiers, Poitiers, France
| | - Adam Petrusek
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Klára Matasová
- Department of Ecology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Carine Delaunay
- Laboratoire Ecologie et Biologie des Interactions, Equipe « Ecologie, Evolution, Symbiose », UMR 7267 CNRS, Université de Poitiers, Poitiers, France
| | - Frédéric Grandjean
- Laboratoire Ecologie et Biologie des Interactions, Equipe « Ecologie, Evolution, Symbiose », UMR 7267 CNRS, Université de Poitiers, Poitiers, France
- * E-mail:
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Viljamaa-Dirks S, Heinikainen S, Torssonen H, Pursiainen M, Mattila J, Pelkonen S. Distribution and epidemiology of genotypes of the crayfish plague agent Aphanomyces astaci from noble crayfish Astacus astacus in Finland. DISEASES OF AQUATIC ORGANISMS 2013; 103:199-208. [PMID: 23574706 DOI: 10.3354/dao02575] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The crayfish plague agent Aphanomyces astaci was isolated from 69 noble crayfish Astacus astacus samples in Finland between 1996 and 2006. All isolates were genotyped using randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Altogether, 43 isolates belonged to the genotype group of Astacus strains (As), which is assumed to represent the genotype originally introduced into Europe around 1860 and into Finland in 1893. There were 26 crayfish plague isolates belonging to the group of Pacifastacus strain I (Ps1), which appeared in Europe after the stocking of the North American species signal crayfish Pacifastacus leniusculus. The geographical distribution of the 2 genotypes in Finland corresponded with the stocking strategies of signal crayfish. The majority of Ps1-strains (83%) were associated with a classical crayfish plague episode involving acute mortality, compared with only 33% of the As-strains. As-strains were found more often by searching for reasons for population declines or permanently weak populations, or through cage experiments in connection with reintroduction programmes. In some water bodies, isolations of the As-strains were made in successive years. This study shows that persistent crayfish plague infection is not uncommon in noble crayfish populations. The described epidemiological features suggest a difference in virulence between these 2 genotypes.
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Affiliation(s)
- S Viljamaa-Dirks
- Finnish Food Safety Authority Evira, OIE reference laboratory for crayfish plague, 70701 Kuopio, Finland.
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26
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Caprioli R, Cargini D, Marcacci M, Cammà C, Giansante C, Ferri N. Self-limiting outbreak of crayfish plague in an Austropotamobius pallipes population of a river basin in the Abruzzi region (central Italy). DISEASES OF AQUATIC ORGANISMS 2013; 103:149-156. [PMID: 23548365 DOI: 10.3354/dao02571] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Crayfish plague, caused by the oomycete Aphanomyces astaci, is a serious disease of European freshwater crayfish and has eliminated entire populations in several European countries. In September 2011, mortality was observed among the Austropotamobius pallipes population of a river basin in the Abruzzi region (central Italy), and A. astaci DNA was detected by PCR in dead crayfish. A systematic survey was carried out to evaluate the spread and the effects of the plague in the river basin. The source of the outbreak remained unknown since North American crayfish species, which frequently act as subclinical carriers of the infection, were not detected in the area. The A. pallipes population disappeared from a river stretch of ~1 km, where A. astaci infection was detected in dead crayfish. However, apparently unaffected crayfish were still present upstream of that area as well as in a tributary that joined the brook in the apparently depopulated stretch. A. astaci infection was not detected in dead individuals collected in the upstream area and tributary. A follow-up visit conducted in the following season showed the presence of A. pallipes in the river stretch hit by the plague. In this outbreak, the spread of the infection could have been limited by a low density of the crayfish population and by the geographic conformation of the river basin, which includes a dense network of small tributaries, characterized by high flow velocity and low water temperature. In this particular setting, crayfish plague outbreaks can remain undetected. This underlines the importance of active monitoring programs aimed at the prompt recognition of both episodes of mortality and the presence of non-indigenous crayfish species.
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Affiliation(s)
- Riccardo Caprioli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy.
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27
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Kusar D, Vrezec A, Ocepek M, Jencic V. Aphanomyces astaci in wild crayfish populations in Slovenia: first report of persistent infection in a stone crayfish Austropotamobius torrentium population. DISEASES OF AQUATIC ORGANISMS 2013; 103:157-169. [PMID: 23548366 DOI: 10.3354/dao02567] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
All 5 crayfish species inhabiting Slovenian freshwaters, of which 3 are indigenous crayfish species (ICS: Astacus astacus, Austropotamobius pallipes, and A. torrentium) and 2 are non-indigenous (NICS: Pacifastacus leniusculus and Cherax quadricarinatus), were inspected for the presence of Aphanomyces astaci, the causative agent of crayfish plague. Wild crayfish populations showing no clinical signs of infection were inspected using A. astaci-specific real-time PCR. In addition, a conventional PCR assay was employed and confirmative sequencing was performed. Out of 88 analyzed crayfish, 15/27 (55.6%) specimens of A. torrentium from Borovnišcˇ%%KERN_ERR%%ica Brook and 4/35 (11.4%) of P. leniusculus from the Mura River tested positive, showing low to moderate levels of infection (agent levels A1-A4 and A1-A3, respectively). Results revealed the presence of A. astaci not only in the resistant NICS but also in ICS, since the infected population of A. torrentium presumably had no contact with the NICS carrier and appeared to sustain A. astaci infection in the 2 sampling years. Although the A. astaci genotype has not yet been identified, a connection between the latent infection in ICS and a Group A strain of A. astaci, co-evolving with A. torrentium since its first introduction to Slovenia, is suggested as the most plausible conclusion. This is the first reported population of the genus Austropotamobius with persistent infection, in addition to the already known populations of the genus Astacus. Findings of the presumed co-evolution of A. astaci and ICS hosts open new perspectives, necessitating additional studies on the presence of A. astaci genotypes in the persistently infected ICS populations.
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Affiliation(s)
- Darja Kusar
- Institute of Microbiology and Parasitology, University of Ljubljana, Ljubljana, Slovenia
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28
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Timing and quantifying Aphanomyces astaci sporulation from the noble crayfish suffering from the crayfish plague. Vet Microbiol 2013; 162:750-755. [DOI: 10.1016/j.vetmic.2012.09.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 09/24/2012] [Accepted: 09/27/2012] [Indexed: 11/23/2022]
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Temporal dynamics of spore release of the crayfish plague pathogen from its natural host, American spiny-cheek crayfish (Orconectes limosus), evaluated by transmission experiments. Parasitology 2013; 140:792-801. [DOI: 10.1017/s0031182012002223] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYThe crayfish plague pathogen, Aphanomyces astaci, is one of the most serious threats to indigenous European crayfish species. The North American invasive spiny-cheek crayfish, Orconectes limosus, is an important source of this pathogen in central and western Europe. We evaluated potential changes in A. astaci spore release rate from infected individuals of this species by experiments investigating the pathogen transmission to susceptible noble crayfish, Astacus astacus. We filtered defined volumes of water regularly to quantify spore concentration, and sampled crayfish tissues at the end of the experiment. The filters and tissues were then tested for the presence of A. astaci DNA by species-specific quantitative PCR. Additionally, we tested the efficiency of horizontal transmission to apparently uninfected O. limosus. The experiments confirmed that A. astaci can be transmitted to susceptible crayfish during intermoult periods, and that the pathogen was more frequently detected in noble crayfish recipients than in American ones. The pathogen spore concentrations substantially varied in time, and significantly increased during moulting of infected hosts. Our study strengthens the evidence that although the likelihood of crayfish plague transmission by water transfer from localities with infected American crayfish might increase when these are moulting or dying, no time-periods can be proclaimed safe.
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Makkonen J, Jussila J, Kortet R, Vainikka A, Kokko H. Differing virulence of Aphanomyces astaci isolates and elevated resistance of noble crayfish Astacus astacus against crayfish plague. DISEASES OF AQUATIC ORGANISMS 2012; 102:129-36. [PMID: 23269387 DOI: 10.3354/dao02547] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Crayfish plague epidemics (caused by Aphanomyces astaci) have been causing population collapses among native European crayfish stocks since the late 1800s. Recent indirect and direct evidence has shown that its virulence has been variable, with native European crayfish even acting as carriers. We tested the differences in A. astaci virulence under experimental conditions using both PsI- and As-genotypes with 3 Finnish noble crayfish Astacus astacus populations. We infected crayfish with adjusted quantities of A. astaci zoospores and monitored the symptoms and mortality of the crayfish. The PsI-genotype isolate caused rapid and total mortality among the tested populations, while the As-genotype isolates expressed more variable virulence. In some cases, mortality among the As-genotype-infected crayfish did not exceed the mortality level of the control group. All of the tested noble crayfish stocks showed lower mortality towards the As-genotype of A. astaci isolated from the River Kemijoki epidemic. We conclude that there are clear differences in virulence between different A. astaci genotypes and also differences in virulence within As-genotypes. Furthermore, we observed clear signs of increased resistance in different populations of noble crayfish towards some of the tested strains belonging to the As-genotype of A. astaci.
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Affiliation(s)
- J Makkonen
- Department of Biology, University of Eastern Finland, Kuopio, Finland.
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Pârvulescu L, Schrimpf A, Kozubíková E, Cabanillas Resino S, Vrålstad T, Petrusek A, Schulz R. Invasive crayfish and crayfish plague on the move: first detection of the plague agent Aphanomyces astaci in the Romanian Danube. DISEASES OF AQUATIC ORGANISMS 2012; 98:85-94. [PMID: 22422132 DOI: 10.3354/dao02432] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Native European crayfish, such as Astacus leptodactylus, are threatened, among other factors, by the crayfish plague agent Aphanomyces astaci, dispersed by invasive North American crayfish. Two of these invaders, Pacifastacus leniusculus and Orconectes limosus, have extended their distribution in the River Danube catchment; the latter was detected for the first time in Romania in 2008. We monitored, at monthly intervals for over 2 yr, occurrence of native A. leptodactylus and invasive O. limosus at 6 sites on the Romanian Danube and checked for the invasive species in 4 of its tributaries. Between January 2009 and March 2011, the relative abundances of O. limosus steadily increased with time, while the native A. leptodactylus dramatically decreased in abundance. O. limosus expanded downstream at a rate of ca. 15 km yr-1; in August 2011, it was already present in the upper 105 km of the Romanian Danube. An agent-specific real-time PCR analyses demonstrated the presence of A. astaci DNA in at least 32% of the analysed invasive (n = 71) and 41% of the native (n = 49) crayfish coexisting in the Danube. Furthermore, A. astaci was also detected in A. leptodactylus captured about 70 km downstream of the O. limosus invasion front (at the time of sampling). Assuming a steady rate of expansion, O. limosus may invade the sensitive Danube delta area in the mid-2060s, even without long-distance dispersal. The crayfish plague agent, however, may reach the delta substantially earlier, through dispersal downstream among populations of native crayfish.
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Affiliation(s)
- Lucian Pârvulescu
- West University of Timisoara, Dept. of Biology and Chemistry, Timisoara, Romania.
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