Inter-Research
Diseases of Aquatic Organisms

ABSTRACT: Swimbladder changes resulting from Anguillicola crassus infection of the European eel Anguilla anguilla have been the subject of several studies reported in the literature. These investigations, however, studied exclusively the status of infection at a given point in time and did not deal with changes in swimbladder infection in eels suffering from anguillicolosis over a period of time. In this study, A. crassus-induced pathological changes were monitored in 78 eels naturally infected in Lake Balaton and subsequently kept in the laboratory, thus excluding the possibility of further infection. During the 3 mo study, the status of the swimbladder was checked by radiographic examination on 4 occasions. At the end of the study the eels were dissected and the gross pathological changes in the swimbladders were compared with the radiographic findings. As compared to their starting condition, by the end of the study the pathological status of the swimbladder had deteriorated in 55% and remained the same in 37% of the cases. Tendency to improvement (1%) and variable findings (7%) were recorded in a low percentage of cases only. With the help of the radiographs presented, the dynamics of A. crassus infection and of changes in the swimbladder of individual eel specimens can be monitored easily.

KEY WORDS: European eel · Anguillicola crassus · Swimbladder infection · Pathological changes · Repeated conventional X-ray · Temporal effect · Dynamics of infection in individuals

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Published in DAO Vol. 64, No. 1 (2005) on April 6
Print ISSN: 0177-5103; Online ISSN: 1616-1580. Copyright © Inter-Research, Oldendorf/Luhe, 2005