419:, where European and American eels spawn. For European eels, this migration involves a journey of about 5500 km. Research has been carried out to precisely quantify the possible damage a given parasite load could have in the ability of a silver eel to migrate and reproduce. In an experiment to assess the energetic cost of the migration in general, it was shown that eels with less than 13% fat reserves would not be capable of reaching their spawning ground. Looking at the effect of an A. crassus burden, however, showed that heavy parasite burdens do affect swimming performance and reproductive output following migration.
54:
33:
345:
leading to a decline in the rate of gas deposition. Mortality may also be linked to secondary bacterial infection, particularly in intensive eel farms. Infected eels are also less resistant to stress, with infections causing large increases in serum cortisol levels (an important primary messenger of stress response in
344:
larvae. High parasitic loads (>10 adult nematodes per eel) can reduce the proportion of oxygen in the swimbladder by about 60% in comparison to uninfected eels. Structural changes include possible alterations in the epithelial cells, hindering processes involved in acidification of the blood and
369:
infection levels. These conditions are the same outlined as ideal for epizootics by Barus and Prokes, 1996. It has been suggested that the highly stressful conditions in the lakes were compounded by the intense parasite presence (in Lake
Balaton, burdens were as high as 30–50 adults and 200 larvae
308:
Infected copepods tend to inhabit epibenthic regions due to their sluggish movement. Benthic fish also acquire greater parasite loads, due to their tendency to prey on epibenthic intermediate hosts or other paratenic hosts. Therefore, the composition of a fishery, such as a lake, could have an
244:
but may also be a fish. The nematode larva reaches its infective stage within this intermediate host. The host is eaten by an eel, and the nematode finds its way from the eel's digestive tract to its swimbladder. An eel with an advanced parasite load shows symptoms such as bleeding lesions and
377:
on eel populations under these conditions. The small size of the eels (<50 cm long) due to the high eel density in the lake actually prevented high parasite loads, and the absence of mosquito insecticides in this case is thought to help explain the lack of mass mortalities.
224:). It was introduced to the European continent in the 1980s, where it was reported independently from Germany and Italy in 1982, having probably been introduced from Taiwan. It is thought to have reached England in 1987 from continental Europe. It is a natural parasite of the
393:
on eel populations are not isolated, but are part of a synergistic effect composed of factors including over-fishing of elvers, habitat loss, global warming and pollution all have significant effects on eel recruitment. Doubt over mostly attributing this drop to
364:
mortalities are from the summer of 1991, in Lake
Balaton, Hungary, and the Vranov reservoir in the Czech Republic during 1994. Both displayed similar characteristics involving low water oxygen levels, coupled with high temperatures, plus high eel densities and
235:
begins when the adult nematode releases thousands of eggs in the eel's swimbladder. The eggs pass through the eel's digestive tract and the larvae emerge in the water and settle onto the substrate. They are ingested by their intermediate host, which is often a
826:
Palstra, A. P.; Heppener, D. F. M.; van
Ginneken, V. J. T.; Székely, C.; van den Thillart, G. E. E. J. M. (2007-11-30). "Swimming performance of silver eels is severely impaired by the swim-bladder parasite Anguillicola crassus".
672:
Würtz, J.; Taraschewski, H.; Pelster, B. (1996-02-01). "Changes in gas composition in the swimbladder of the
European eel (Anguilla anguilla) infected with Anguillicola crassus (Nematoda)".
327:
Third, the larvae remain for longer within the host's swimbladder wall whilst developing into the fourth larval stage, as opposed to moving directly through it (as occurs in
Pacific eels).
216:
spp.) and appears to spread easily among eel populations after introduction to a body of water. It is considered to be one of the threats to the sustainability of populations of
858:
Kennedy, C. R. (1993). "Introductions, spread and colonization of new localities by fish helminth and crustacean parasites in the
British Isles: a perspective and appraisal".
245:
swimbladder collapse. The eel becomes more susceptible to disease, its rate of growth slows, and if the infestation is severe enough, it may die. Since the swimbladder is the
633:
286:
hosts in its transmission, such as a number of freshwater fish, amphibians, snails and aquatic insects. Despite there being no record of the use of paratenic hosts in
1072:
941:
610:"Anguillicola crassus and A. globiceps (Nematoda: Dracunculoidea) parasitic in the swimbladder of eels (Anguilla japonica and A. anguilla) in East Asia: a review"
389:
has been repeatedly blamed for the dramatic drop in eel recruitment during the 1980s, although this level of blame has receded in recent years. The effects of
357:
Mortalities are both more intense and identifiable within eel farms than in the wild. Thus, it is difficult to compare losses between wild and farmed eels.
791:
Van Den
Thillart, G.; Van Ginneken, V.; Körner, F.; Heijmans, R.; Van Der Linden, R.; Gluvers, A. (2004-08-01). "Endurance swimming of European eel".
1059:
1180:
1147:
524:
435:
Kuwahara A., Niimi H. & Itagaki H. (1974). "Studies on a nematode parasitic in the air bladder of the eel I. Descriptions of
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53:
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Parallels between Lake
Balaton and another water body, the Neusiedler See in Austria, could counter the extreme effects of
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larvae have the ability to infect several species of freshwater cyclopoid copepod, as well as estuarine copepods e.g.
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larvae into the fourth stage and have lower rates of encapsulation, thereby permitting longer rates of survival.
340:
The hosts' swimbladder wall becomes inflamed as cells undergo fibrosis, which can prevent further invasion by
973:
468:
148:
879:
Kennedy, C. R.; Fitch, D. J. (1990). "Colonisation, larval survival, and epidemiology of the nematode
249:
organ which allows the eel to swim, a severe parasite infestation can hamper its ability to reach its
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The suitability of paratenic hosts in facilitating transmission differs according to species, with
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649:"Host reaction in paratenic fish hosts against 3rd stage larvae of Anguillicola crassus"
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E. G. Heitlinger; D. R. Laetsch; U. Weclawski; Y. S. Han; H. Taraschewski (2009).
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This allows transmission of the parasite within a wide range of aquatic habitats.
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1005:
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725:"Anguillicolosis of the European eel (Anguilla anguilla) in the Czech Republic"
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65:
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Sébastien
Wielgoss; Horst Taraschewski; Axel Meyer; Thierry Wirth (2008).
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85:
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Kennedy, C R (2007-06-01). "The pathogenic helminth parasites of eels".
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transmission cycles in Asia, this possibility has not been rejected.
75:
967:
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301:(closed swimbladder) fish. The latter allow further development of
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The parasite could possibly impair the migration of eels to the
971:
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experienced a similar decline (98%) in North
America, despite
412:
having not been introduced to that ecosystem at that point.
272:
Three significant changes were made to the life cycle of
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suffered a large drop in recruitment, the American eel
912:
infestations in Germany and in German eel imports".
551:, an invader of declining North Atlantic eel stocks"
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398:stemmed from an observation that during the period
829:Journal of Experimental Marine Biology and Ecology
297:(open swimbladder) fish being less suitable than
547:"Population structure of the parasitic nematode
8:
632:: CS1 maint: multiple names: authors list (
276:which facilitated its success in colonizing
968:
439:sp. n. (Philometridea, Anguillicolidae)".
31:
20:
491:
481:
464:in the intestinal wall of Japanese eels"
945:as a parasite of eel swimbladders (pdf)
608:K., Nagasawa; G., Kim, Y.; H., Hirose.
428:
647:C., Székely; J., Pazooki; K., Molnár.
625:
521:(Kuwahara, Niimi & Itagaki, 1974)"
7:
723:V., Baruš; F., Moravec; M., Prokeš.
164:(Kuwahara, Niimi & Hagaki, 1974)
954:(Kuwahara, Niimi and Hagaki, 1974)"
928:10.1111/j.1439-0426.1989.tb00568.x
901:10.1111/j.1095-8649.1990.tb05588.x
360:The best documented cases of mass
182:Kuwahara, Niimi & Hagaki, 1974
14:
908:Koops, H.; Hartmann, F. (1989). "
460:"Massive encapsulation of larval
442:Japanese Journal for Parasitology
805:10.1111/j.0022-1112.2004.00447.x
762:10.1111/j.1365-2761.2007.00821.x
572:10.1111/j.1365-294X.2008.03855.x
525:World Register of Marine Species
256:The state of being colonized by
52:
915:Journal of Applied Ichthyology
313:within a particular locality.
268:Adaptation to the European eel
1:
1181:Nematodes described in 1974
841:10.1016/j.jembe.2007.08.003
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686:10.1017/s003118200008481x
176:
169:
154:
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49:Scientific classification
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39:
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23:
1012:Anguillicoloides crassus
982:Anguillicoloides crassus
750:Journal of Fish Diseases
519:Anguillicoloides crassus
462:Anguillicoloides crassus
233:Anguillicoloides crassus
192:Anguillicoloides crassus
158:Anguillicoloides crassus
25:Anguillicoloides crassus
889:Journal of Fish Biology
860:Journal of Fish Biology
793:Journal of Fish Biology
469:Parasites & Vectors
309:important influence of
202:worm that lives in the
883:, parasite in the eel
872:10.1006/jfbi.1993.1128
483:10.1186/1756-3305-2-48
448:(5): 275–279. OpenURL
228:in its native range.
952:Anguillicola crassus
881:Anguillicola crassus
549:Anguillicola crassus
260:nematodes is termed
179:Anguillicola crassus
42:Anguillicola crassus
16:Species of roundworm
437:Anguillicola crassa
322:Eurytemora affinis.
282:First, it utilizes
231:The life cycle of
40:Four specimens of
1163:
1162:
1125:Open Tree of Life
974:Taxon identifiers
885:Anguilla Anguilla
729:www.cabdirect.org
653:www.cabdirect.org
614:www.cabdirect.org
566:(15): 3478–3495.
559:Molecular Ecology
405:Anguilla rostrata
222:Anguilla anguilla
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852:Further reading
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936:External links
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149:Binomial name
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1006:Wikispecies
400:A. anguilla
362:A. anguilla
353:Populations
278:A. anguila.
106:Camallanida
96:Secernentea
1170:Categories
943:A. crassus
734:2015-10-25
658:2015-10-25
619:2015-10-25
530:August 13,
423:References
410:A. crassus
396:A. crassus
391:A. crassus
387:A. crassus
375:A. crassus
370:per eel).
367:A. crassus
342:A. crassus
318:A. crassus
311:A. crassus
303:A. crassus
299:physoclist
295:physostome
288:A. crassus
274:A. crassus
242:crustacean
1176:Spirurida
922:: 41–45.
813:1095-8649
770:1365-2761
694:0031-1820
476:(1): 48.
382:Migration
284:paratenic
253:grounds.
240:or other
197:parasitic
134:Species:
72:Kingdom:
66:Eukaryota
1078:11474733
997:Q1859493
991:Wikidata
778:17498176
628:cite web
588:14804458
580:18727770
502:19832983
316:Second,
251:spawning
213:Anguilla
200:nematode
171:Synonyms
112:Family:
86:Nematoda
82:Phylum:
76:Animalia
62:Domain:
1140:7186368
1065:5890148
710:9612388
702:8851864
493:2766375
349:fish).
347:teleost
247:buoyant
238:copepod
122:Genus:
102:Order:
92:Class:
1153:458994
1137:uBio:
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1117:208846
1052:391601
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1148:WoRMS
1091:93709
1073:IRMNG
1039:8G39F
706:S2CID
595:(PDF)
584:S2CID
554:(PDF)
195:is a
1060:GBIF
809:ISSN
774:PMID
766:ISSN
698:PMID
690:ISSN
634:link
576:PMID
532:2010
498:PMID
208:eels
1099:NBN
1086:ISC
1034:CoL
1021:ADW
956:at
924:doi
897:doi
868:doi
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801:doi
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488:PMC
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