The swimbladder nematodeAnguillicola crassusin the European eelAnguilla anguillaand the Japanese eelAnguilla japonica: differences in susceptibility and immunity between a recently colonized host and the original host

2006 ◽  
Vol 80 (2) ◽  
pp. 129-136 ◽  
Author(s):  
K. Knopf
Keyword(s):  
Anguilla Anguilla ◽  
Preliminary Evidence ◽  
Japanese Eel ◽  
Indigenous Populations ◽  
Acquired Immunity ◽  
European Eel ◽  
New Host ◽  
Protective Function ◽  
Original Host ◽  
Third Stage

AbstractThe swimbladder nematodeAnguillicola crassusoriginates from Asia where it is a parasite of the Japanese eelAnguilla japonica. After its introduction to Europe about 25 years ago, the parasite spread rapidly within the indigenous populations of the European eelAnguilla anguillaand subsequently the prevalence and mean intensity appeared to stabilize. Under experimental and aquaculture conditions the naïve new host appears to be more susceptible toA. crassuscompared to the original host. Both eel species develop a immune response againstA. crassus. The antibody response is well characterized for the European eel, but poorly characterized for the Japanese eel. It remains unclear if antibodies have any protective function againstA. crassus. Encapsulation of larvae ofA. crassuscan be observed in naturally infected European eels. However, encapsulation of larvae following experimental infection has not been detected in European eels, but only in Japanese eels. Reinfection experiments and intraperitoneal injection ofA. crassushomogenates failed to demonstrate the development of acquired immunity in European eels. Immunization with irradiated third stage larvae provided preliminary evidence for acquired immunity againstA. crassusin the Japanese eel, but not in the European eel.

The life cycle of Paraquimperia tenerrima: a parasite of the European eel Anguilla anguilla

2005 ◽  
Vol 79 (2) ◽  
pp. 169-176 ◽  
Author(s):  
J.A. Shears ◽  
C.R. Kennedy
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Temperature Dependent ◽  
Free Living ◽  
Freshwater Invertebrate ◽  
Third Stage ◽  
History Of ◽  
Whole Life Cycle

AbstractPrevious studies on the life history of the nematode eel specialist Paraquimperia tenerrima (Nematoda: Quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. In the laboratory, eggs failed to hatch below 10°C, hatching occurring only at temperatures between 11 and 30°C. Survival of the free-living second stage larvae (L2) was also temperature dependent, with maximal survival between 10 and 20°C. Total survival of the free-living stages (eggs and L2) is unlikely to exceed a month at normal summer water temperatures, confirming that parasite could not survive the 6 month gap between shedding of eggs in spring and infection of eels in early winter outside of a host. Eels could not be infected directly with L2, nor could a range of common freshwater invertebrate species. Third stage larvae (L3) resembling P. tenerrima were found frequently and abundantly in the swimbladder of minnows Phoxinus phoxinus from several localities throughout the year and were able to survive in this host in the laboratory for at least 6 months. Third stage larvae identical to these larvae were recovered from minnows experimentally fed L2 of P. tenerrima, and eels infected experimentally with naturally and experimentally infected minnows were found to harbour fourth stage larvae (L4) and juvenile P. tenerrima in their intestines. Finally, the whole life cycle from eggs to adult was completed in the laboratory, confirming that minnows are an obligate intermediate host for P. tenerrima.

scholarly journals Transcriptome analyses of Anguillicola crassus from native and novel hosts

2014 ◽  
Author(s):  
Emanuel Heitlinger ◽  
Horst H. Taraschewski ◽  
Urszula Weclawski ◽  
Karim Gharbi ◽  
Mark Blaxter
Keyword(s):  
Population Differentiation ◽  
Anguilla Anguilla ◽  
Common Garden ◽  
European Eel ◽  
New Host ◽  
Phenotypic Differences ◽  
Secretion Signal ◽  
Anguillicola Crassus ◽  
The Face ◽  
Parasite Populations

Anguillicola crassus is a swim bladder nematode of eels. The parasite is native to the Asian eel Anguilla japonica, but was introduced to Europe and the European eel Anguilla anguilla in the early 1980s. A Taiwanese source has been proposed for this introduction. In the new host in the recipient area, the parasite appears to be more pathogenic. As a reason for these differences, genetically fixed differences in infectivity and development between Taiwanese and European A.crassus have been described and disentangled from plasticity induced by different host environments.To explore whether transcriptional regulation is involved in these lifecycle differences, we have analysed a “common garden”, cross infection experiment, using deep-sequencing transcriptomics. Surprisingly, in the face of clear phenotypic differences in life history traits, we identified no significant differences in gene expression between parasite populations or between experimental host species. From 120,000 SNPs identified in the transcriptome data we found that European A. crassus were not a genetic subset of the Taiwanese nematodes sampled. The loci that have the major contribution to the European-Taiwanese population differentiation show an enrichment of synonymous and non-coding polymorphism. This argues against positive selection in population differentiation. However, genes involved in protein processing in the endoplasmatic reticulum membrane and genes bearing secretion signal sequences were enriched in the set of genes most differentiated between European and Taiwanese A. crassus. These genes could be a source for the phenotypically visible genetically fixed differences between European and Taiwanese A. crassus.

scholarly journals Transcriptome analyses of Anguillicola crassus from native and novel hosts

2014 ◽  
Author(s):  
Emanuel Heitlinger ◽  
Horst H. Taraschewski ◽  
Urszula Weclawski ◽  
Karim Gharbi ◽  
Mark Blaxter
Keyword(s):  
Population Differentiation ◽  
Anguilla Anguilla ◽  
Common Garden ◽  
European Eel ◽  
New Host ◽  
Phenotypic Differences ◽  
Secretion Signal ◽  
Anguillicola Crassus ◽  
The Face ◽  
Parasite Populations

Anguillicola crassus is a swim bladder nematode of eels. The parasite is native to the Asian eel Anguilla japonica, but was introduced to Europe and the European eel Anguilla anguilla in the early 1980s. A Taiwanese source has been proposed for this introduction. In the new host in the recipient area, the parasite appears to be more pathogenic. As a reason for these differences, genetically fixed differences in infectivity and development between Taiwanese and European A.crassus have been described and disentangled from plasticity induced by different host environments.To explore whether transcriptional regulation is involved in these lifecycle differences, we have analysed a “common garden”, cross infection experiment, using deep-sequencing transcriptomics. Surprisingly, in the face of clear phenotypic differences in life history traits, we identified no significant differences in gene expression between parasite populations or between experimental host species. From 120,000 SNPs identified in the transcriptome data we found that European A. crassus were not a genetic subset of the Taiwanese nematodes sampled. The loci that have the major contribution to the European-Taiwanese population differentiation show an enrichment of synonymous and non-coding polymorphism. This argues against positive selection in population differentiation. However, genes involved in protein processing in the endoplasmatic reticulum membrane and genes bearing secretion signal sequences were enriched in the set of genes most differentiated between European and Taiwanese A. crassus. These genes could be a source for the phenotypically visible genetically fixed differences between European and Taiwanese A. crassus.

scholarly journals Vaccination of eels (Anguilla japonicaandAnguilla anguilla) againstAnguillicola crassuswith irradiated L3

Parasitology ◽  
2008 ◽  
Vol 135 (5) ◽  
pp. 633-640 ◽  
Author(s):  
K. KNOPF ◽  
R. LUCIUS
Keyword(s):  
Immune Responses ◽  
Antibody Response ◽  
Anguilla Anguilla ◽  
Challenge Infection ◽  
Antibody Responses ◽  
Single Infection ◽  
European Eel ◽  
Anguillicola Crassus ◽  
Original Host ◽  
Protection Against Infection

SUMMARYThe original host of the swimbladder nematodeAnguillicola crassus, the Japanese eel (Anguilla japonica) and the recently colonized European eel (Anguilla anguilla) were immunized with 40 irradiated (500 Gy) 3rd-stage larvae (L3) of this parasite and challenged with an infection of 40 normal L3. The immunization induced a significant reduction of the number of adult worms developing from the challenge infection inA. japonica, but not inA. anguilla. The induced resistance (calculated using the relation of the number of adult worms in immunized eels and in non-immunized control eels) inA. japonicawas 87·3%±30·4%. Following a single infection, the percentage of adult worms found inA. japonicawas lower as compared toA. anguilla, and the few adult worms were much smaller, revealing a lower susceptibility ofA. japonicatoA. crassusin comparison toA. anguilla. Both eel species developed an antibody response againstA. crassus, but the level of antibody responses was not positively correlated with the protection against infection, suggesting that the antibody response is not a key element in resistance of eels againstA. crassus. This study suggests that the original host ofA. crassusis able to mount efficient protective immune responses against its parasite, whereas the newly acquired host seems to lack this ability.

scholarly journals Checklist of the parasites of European eel Anguilla anguilla (Linnaeus, 1758) (Anguillidae) in Poland

2020 ◽  
Vol 8 ◽  
Author(s):  
Joanna Dzido ◽  
Leszek Rolbiecki ◽  
Joanna Izdebska ◽  
Rafał Bednarek
Keyword(s):  
Parasite Species ◽  
Developmental Stages ◽  
Anguilla Anguilla ◽  
European Eel ◽  
New Host ◽  
Freshwater Habitats ◽  
Acanthocephalus Lucii ◽  
Infection Parameters ◽  
New Host Records ◽  
Raphidascaris Acus

The present paper lists all parasite species of the European eel Anguilla anguilla (Linnaeus, 1758), recorded in Poland, in both its saltwater and freshwater habitats. The list has been drawn up, based on data acquired since 1844. The majority of included parasite species are presented with fish infection parameters together with data on their developmental stages and occupied microhabitats, localities and dates of collection of the eels themselves. The database includes 62 parasite taxa (including 50 species, nine identified to the genus level and three to higher taxa), representing at least 47 genera and 39 families. The most frequently-noted parasites of the European eel are the cestode Bothriocephalus claviceps, the nematodes Anguillicoloides crassus, Camallanus lacustris and Raphidascaris acus and the acanthocephalan Acanthocephalus lucii. Four alien species have been noted from this host: A. crassus, the monogeneans Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and the acanthocephalan Paratenuisentis ambiguus. The present list includes both new host records and earlier records not included in previous lists of parasites of eels.

Regulation ofAnguillicola crassus(Nematoda) infrapopulations in their definitive host, the European eel,Anguilla anguilla

Parasitology ◽  
2008 ◽  
Vol 135 (14) ◽  
pp. 1707-1716 ◽  
Author(s):  
G. FAZIO ◽  
P. SASAL ◽  
C. DA SILVA ◽  
B. FUMET ◽  
J. BOISSIER ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Anguilla Anguilla ◽  
The Body ◽  
European Eel ◽  
Swim Bladder ◽  
Experimental Conditions ◽  
Larval Stages ◽  
Resource Limited ◽  
Third Stage ◽  
Opposite Sex

SUMMARYThe parasitic nematodeAnguillicola crassuswas recently introduced into populations of the European eel,Anguilla anguilla. We investigated, under experimental conditions, the regulation ofA. crassusinfrapopulations. We tested the effects of (1) the resource-limited habitat of the parasite and (2) the coexistence of several developmental stages in its niche (the swim-bladder) on the composition of the infrapopulations. The results revealed that the respective effects of these factors differed substantially during the course of the infection. Third-stage larvae (L3s) establishment would not be constrained by the size of the swim-bladder. Their moult to fourth-stage larvae (L4s) would be accelerated as the number of L3s increased. The moulting time of L4s to adults would be reduced by males and would be constrained by the size of the swim-bladder. However, the moult of L4s to adults and their further development would be synchronized with those of the opposite sex. At the time of mating, the number of males and the body weight of adults would depend on the size of the swim-bladder. Soon after the laying of eggs, the developmental constraint on the late L3s would decrease. When adults die, constraints would cease and late larval stages would moult to become adults.

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