Aquat. Living Resour.
Volume 27, Number 2, April-June 2014
|Page(s)||99 - 106|
|Published online||16 December 2014|
Early diagnosis of enteromyxosis in intensively reared sharpsnout seabream, Diplodus puntazzo
Department of Ichthyology and Aquatic Environment,
School of Agricultural Sciences, University of Thessaly, Fytokou str., 38445
a Corresponding author:
Accepted: 27 November 2014
Myxozoans are metazoan parasites which are highly pathogenic in commercially important fish, particularly in aquaculture. Enteromyxosis is an economically significant disease caused by the myxosporean parasite Enteromyxum leei. Presently, early diagnosis of enteromyxosis in sharpsnout seabream was achieved by monitoring fish on a time-scale scheduled basis in combination with a validated molecular diagnostic technique. Two different successive fish batches of a commercial fish farm were monitored starting from the first month of on-growing in sea cages until fish reached commercial size. Fish weight and water temperature differentially ranged between them. E. leei detection was performed both by classical microscopic observation of fresh smears and by quantitative polymerase chain reaction (qPCR) while prevalence, mean intensity and mortality rate were calculated. In total, 520 fish were screened; 320 from the first batch and 200 from the second one. Parasitosis illustrated a seasonal occurrence pattern (spring and summer). When qPCR was used as a diagnostic method, enteromyxosis was diagnosed earlier with more increased prevalence compared to the microscopic observation. In this case, the parasite was detected at the lowest water temperature that has ever been recorded (14.7 °C), during the first month of on-growing in sea cages. The two-factor combination of water temperature and fish weight proved to be the most significant factor that could determine the emergence and development of parasitosis and smaller fish proved to be more susceptible. Mortality was influenced by both prevalence and intensity of parasitosis. An earlier diagnosis and identification of all developmental stages of the parasite throughout its life cycle was verified with qPCR, significantly before any outbreak occurred. The latter could become a key diagnostic tool for the control of enteromyxosis, allowing stakeholders and fish farmers to adopt all necessary precautionary measures minimizing economic loss in sharpsnout seabream intensive farming.
Key words: Fish disease / Early diagnosis / Enteromyxosis / qPCR / Myxozoan parasites / Enteromyxum leei / Sparidae / Sharpsnout seabream
© EDP Sciences, IFREMER, IRD 2014
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.