Comparative study of X-ray computerised tomography and conventional X-ray methods in diagnosis of swimbladder infection in eels caused by Anguillicola crassus

Abstract

To date, swimbladder lesions due to Anguillicola crassus infection of the European eelAnguilla anguilla have so far been studied only by conventional X-ray methods. This is the first study to report the use of computerised tomography (CT) for studying lesions induced by anguillicolosis. Of 50 eels caught by electrofishery from Lake Balaton, Hungary, in autumn 2002 and pre-selected by a conventional X-ray method, 22 specimens were examined with a Siemens Somatom Plus S40 spiral CT scanner. Tomograms, radiographs and photographs of 5 of these, showing anguillicolosis-induced swimbladder lesions of varying severity, are presented. Computerised tomograms provide information on the inner structure, air content and wall thickness of the swimbladder as well as on the number of worms it contains. When the swimbladder is not severely affected or not completely filled with worms, computerised tomography provides adequate data on the shape of the swimbladder, thickness of the swimbladder wall and the location of worms in the lumen. However, in more severe cases, i.e. when the swimbladder is tightly packed with worms or contains no air as a result of wallthickening, this method fails to determine the number and location of helminths or the thickness of the swimbladder wall.KEY WORDS: European eel · Anguillicola crassus · Swimbladder infection · Pathological changes · X-ray computerised tomography · Conventional X-ray Resale or republication not permitted without written consent of the publisher

Radiodiagnostic method for studying the dynamics of Anguillicola crassus (Nematoda: Dracunculoidea) infection and pathological status of the swimbladder in Lake Balaton eels

“…In some eels, the condition of the swimbladder did not change, but in the majority of cases the swimbladder deteriorated. The findings of the current study also indicate that statements made in earlier works of the research Beregi et al 1998, 2001, Székely et al 2004 require certain modifications. These authors were of the opinion that the total absence of swimbladder contours on the radiographs consistently indicated a marked thickening of the swimbladder wall accompanied by a parallel reduction in the swimbladder lumen.…”

“…The tags were read with an AEG ID ARE H5-ISO apparatus. After a 10 d adaptation period following collection, the eels were X-rayed using the method of Beregi et al (1998Beregi et al ( , 2001 and Székely et al (2004). The examination was repeated 3 times (4, 8 and 12 wk after the first X-ray examination).…”

“…The wide-ranging potential for using radiodiagnostic methods in fish medicine has also been suggested by the studies of Böttcher & Böttcher (2000, 2003a. Conventional Xray methods and X-ray computerised tomography have recently been compared by Székely et al (2004) to determine their value in the diagnosis of swimbladder infection in eels.…”

Comparative imaging of European eels (Anguilla anguilla) for the evaluation of swimbladder nematode (Anguillicoloides crassus) infestation

“…Computed tomography (CT) has also been used to show gas content, inner structure and wall thickness of eel swimbladders (Székely et al . ). Székely et al .…”

Advantages and limitations of X-ray and computed tomography systems for the study of the skeleton in meagre (Argyrosomus regius)

“…Computed tomography has also been proved to be useful in other scientific areas, such as paleontology (López‐Polín et al., 2008), geology (Duchesne et al., 2009), food technology (Fulladosa et al., 2010a,b), carcass classification and quality assessment of livestock (Kolstad, 2001; Font i Furnols et al., 2009) and aquaculture products (Rye, 1991; Kolstad et al., 2008). Regarding fish biology, CT has been used for several purposes, such as comparative and descriptive morphological studies (Metscher, 2009; Leysen et al., 2011), the diagnosis of helminth infection in the swimbladder of European eel (Székely et al., 2004), the evaluation of testis maturation in this species (Müller et al., 2004) and diagnosis skeletal abnormalities in ornamental fish (Bakal et al., 1998). However, there is limited information about the use of such technology in studying fish skeleton and its morphological disorders (Garland et al., 2002).…”