anguillicolosis
Index
- Pictures
- Identity
- Pathogen/s
- Overview
- Host Animals
- Hosts/Species Affected
- Distribution
- Distribution Table
- Pathology
- Diagnosis
- List of Symptoms/Signs
- Epidemiology
- Impact Summary
- Impact
- Zoonoses and Food Safety
- Disease Treatment
- Prevention and Control
- References
- Organizations
- Contributors
- Distribution Maps
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Top of pageOverview
Top of pageAnguillicoloides crassus was first described from Anguilla japonica and Anguilla anguilla in eel farms in Japan by Kuwahara et al. (1974). Around this time, eel farming was expanding in Japan, and in order to increase production non-native eels, especially Anguilla anguilla, were imported from Europe. Most eel farms were concentrated in the south-western provinces of Japan and Anguillicoloides crassus was recorded from Aichi prefecture, Hamamatsu, Shizuoka prefecture and Honshu between 1972 and 1974. It is now known that it was actually present in Japan in 1969, but was then misidentified as Anguillicola globiceps by Egusa et al. (1969). It was almost certainly present at this time in China where it was also confused with Anguillicola globiceps by Wang and Zhao (1980), but the presence of Anguillicoloides crassus in China in Hubei and Fujian was later confirmed by Moravec and Taraschewski (1988) and Zhang (1995). It has subsequently been reported from Korea by Kim et al. (1989) and from Taiwan by Ooi et al. (1996) and Münderle et al. (2006).
Host Animals
Top of pageAnimal name | Context | Life stage | System |
---|---|---|---|
Anguilla anguilla (European eel) | Domesticated host; Wild host | Aquatic|Adult; Aquatic|Fry | Enclosed systems/Freshwater recirculating systems; Enclosed systems/Ponds; Enclosed systems/Raceways / running water ponds; Enclosed systems/Tanks |
Anguilla japonica (Japanese eel) | Domesticated host; Wild host | Aquatic|Adult; Aquatic|Fry | Enclosed systems/Ponds |
Anguilla rostrata (american eel) | Domesticated host; Wild host | Aquatic|Adult; Aquatic|Fry | |
Ariosoma balearicum | Experimental settings |
Hosts/Species Affected
Top of pageThe only species deleteriously affected by Anguillicoloides crassus are the Atlantic eels, Anguilla anguilla and Anguilla rostrata. The parasite is harmless to Anguilla japonica and other species of Pacific eel. It appears that the parasite and Anguilla japonica may have co-evolved together such that this eel has acquired a measure of resistance to Anguillicoloides crassus (Egusa, 1979; Kim et al., 1989; Knopf and Lucius, 2008).
Distribution
Top of pageFurther information
It would appear that Anguillicoloides crassus was originally restricted to East Asia throughout which it is probably widespread and endemic, especially in China, Japan, Korea and Taiwan (there are not many records of its being definitely identified in China, probably because as a non-pathogenic species it is likely to be considered unimportant, and because of its similarity to Anguillicola globiceps). It is likely that it is present in other countries in this region and it has been reported from Thailand (Moravec, 2006) but there have been very few or no published reports of eel parasites from many parts of Eastern Asia. Its natural range probably coincides with that of its preferred host Anguilla japonica.
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 10 Jan 2020Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
|||||||
Egypt | Present | Introduced | Invasive | ||||
Morocco | Present, Localized | Introduced | Invasive | Known since 1999 | |||
Réunion | Present, Localized | Introduced | Invasive | Reported from African eel species, and believed to have been introduced by man | |||
Tunisia | Present, Localized | Introduced | Invasive | In one lake system, but extending range | |||
Asia |
|||||||
China | Present | Present based on regional distribution. | |||||
-Fujian | Present | Native | In culture | ||||
-Hubei | Present | Native | In culture | ||||
Japan | Present | Present based on regional distribution. | |||||
-Hokkaido | Present, Widespread | Native | Especially in culture | ||||
-Honshu | Present, Widespread | Native | Culture and wild | ||||
South Korea | Present | Native | Reported from culture | ||||
Taiwan | Present, Widespread | Native | Wild and in culture | ||||
Thailand | Present | ||||||
Turkey | Present | Introduced | Invasive | In several rivers | |||
Europe |
|||||||
Austria | Present, Localized | Introduced | Invasive | Foci in stocked lakes | |||
Belarus | Present | Introduced | Invasive | ||||
Belgium | Present, Widespread | Introduced | Invasive | First records in 1980s | |||
Czechia | Present, Widespread | Introduced | Invasive | Introduced with eel stocking | |||
Denmark | Present, Widespread | Introduced | Invasive | Introduced with eel stocking | |||
Estonia | Present | Introduced | Invasive | ||||
France | Present, Widespread | Introduced | Invasive | Early introduction into south | |||
Germany | Present, Widespread | Introduced | Invasive | First record from Europe in Weser-Ems in 1982. Now in all major rivers | |||
Greece | Present, Localized | Introduced | Invasive | ||||
Hungary | Present, Localized | Introduced | Invasive | Usually in stocked lakes, especially Lake Balaton | |||
Ireland | Present, Widespread | Introduced | Invasive | First report 1998, but now spreading rapidly. Introduced with eel trade | |||
Italy | Present, Widespread | Introduced | Invasive | Introduced with eels imported from France. Mainly in eel culture | |||
Netherlands | Present, Widespread | Introduced | Invasive | First reported soon after arrival in Europe | |||
North Macedonia | Present | ||||||
Norway | Present, Localized | Introduced | Invasive | Slower colonisation near limit of the species' range | |||
Poland | Present, Widespread | Introduced | Invasive | ||||
Portugal | Present, Widespread | Introduced | Invasive | Often in coastal lagoons | |||
Russia | Present | Present based on regional distribution. | |||||
-Central Russia | Present, Localized | Introduced | Invasive | Mainly around Kaliningrad and Baltic Sea | |||
Slovakia | Present, Localized | Introduced | Invasive | In River Danube system | |||
Spain | Present, Localized | Introduced | Invasive | Localisation may reflect areas of study | |||
Sweden | Present, Localized | Introduced | Invasive | Initially only thermal effluents but now spreading more widely in south | |||
United Kingdom | Present, Widespread | Introduced | Invasive | Introduced with eel trade in south and east in 1987. Now widespread all over including Scotland | |||
North America |
|||||||
Canada | Present | Present based on regional distribution. | |||||
-New Brunswick | Present, Widespread | Introduced | Invasive | ||||
-Newfoundland and Labrador | Present, Widespread | Introduced | Invasive | ||||
-Nova Scotia | Present, Widespread | Introduced | Invasive | ||||
-Prince Edward Island | Present, Widespread | Introduced | Invasive | ||||
United States | Present | Present based on regional distribution. | |||||
-Maine | Present, Widespread | Introduced | Invasive | ||||
-Maryland | Present, Widespread | Introduced | Invasive | ||||
-Massachusetts | Present, Widespread | Introduced | Invasive | ||||
-New York | Present, Localized | Introduced | Invasive | In Hudson River watershed | |||
-North Carolina | Present | Introduced | Invasive | ||||
-Rhode Island | Present | Introduced | Invasive | ||||
-South Carolina | Present, Localized | Introduced | Invasive | ||||
-Texas | Present | Introduced | Invasive | First record in N. America; First reported: circa 1995 |
Pathology
Top of pageOn paratenic hosts
Diagnosis
Top of pageLive infected Anguilla anguilla can seldom if ever be recognised as such with any degree of certainty. Aberrant swimming behaviour may suggest infection, but it is rarely observed and may well have other causes. The only certain method of diagnosis is post mortem examination of the swimbladder. Infected swimbladders may be recognised as such if the intensity of infection is high, but only finding of adults in the swimbladder lumen or of L4s in the swimbladder wall can confirm infection.
List of Symptoms/Signs
Top of pageSign | Life Stages | Type |
---|---|---|
Finfish / Fish swimming near surface - Behavioural Signs | Aquatic|Adult | Sign |
Finfish / Generalised lethargy - Behavioural Signs | Aquatic|Adult | Sign |
Finfish / Organs contain cysts or parasites - Organs | Aquatic|Adult; Aquatic|Fry | Diagnosis |
Epidemiology
Top of pageLife cycle
Impact Summary
Top of pageCategory | Impact |
---|---|
Fisheries / aquaculture | Negative |
Native fauna | Negative |
Other | Negative |
Impact
Top of pageEconomic impact
Despite many reports and references to the damage caused by Anguillicoloides crassus to Anguilla anguilla in eel farms in the Far East, especially in Japan, and to eels in Europe, there is little or no information actually published to quantify the damage in economic terms. Køie (1991), for example, refers to mortalities of 15-65% in a Dutch eel farm and increased mortalities from 10-20 % in other eel farms, but without placing any economic value on these losses.
Zoonoses and Food Safety
Top of pageThere is no danger of Anguillicoloides crassus ever infecting or being transmitted to man, as it is so specific to eels.
Disease Treatment
Top of pageAlthough Anguillicoloides crassus is capable of causing disease in Anguilla anguilla both in eel farms and in natural habitats, no method of control or treatment of natural infections in lakes or rivers has yet been shown to be practicable. Such attempts at treatment as have been made have focused instead upon treatment in eel farms. There appear to have been no trials to treat Anguillicoloides crassus in Anguilla japonica in east Asia, as the parasite is not considered to be pathogenic (Nagasawa et al.1994), especially if the eel ponds are well managed (Han YuSan et al., 2008). Unsuccessful attempts were made in Japan to prevent infection by reducing levels of copepods in eel farms (Egusa and Hirose, 1983). Pressure to find a treatment declined as cultivation of Anguilla anguilla in Japan was abandoned because of the parasite.
Prevention and Control
Top of pageNo method of control or treatment of natural infections in lakes or rivers has yet been shown to be practicable. Such attempts as have been made have focused instead upon treatment in eel farms. When Anguillicoloides crassus was recognised as an important pathogen of imported Anguilla anguilla in eel farms in Japan, attempts were made to reduce levels of copepods in the farms by increasing the flow of water through them, but this was not often feasible and even less often effective. The use of chemicals such as trichlorfon to kill copepods in eel ponds was considered to be relatively ineffective as well as being undesirable in view of the certain environmental contamination of the water in the pond and in its outflow (Egusa and Hirose, 1983). Pressure to find a treatment declined as cultivation of Anguilla anguilla in Japan was abandoned because of the parasite.
References
Top of pageSures B; Knopf K, 2004. Parasites as a threat to freshwater eels? Science, 304:205-206.
Tesch FW, 1999. Der Aal, 3rd edn. Berlin: Parey Publisher.
Distribution References
CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Organizations
Top of pageDenmark: North European and Baltic Network on Invasive Alien Species (NOBANIS), Web-based service, nobanis@sns.dk, http://www.nobanis.org/
Contributors
Top of page04/10/09 Original text by:
Clive Kennedy, University of Exeter, School of Biosciences, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
Distribution Maps
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