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Dexamethasone treatment affects skin mucous cell density in Gyrodactylus derjavini infected Salmo salar

Published online by Cambridge University Press:  12 April 2024

S.H. Olafsdottir
Affiliation:
Department of Veterinary Microbiology, Section of Fish Diseases, Royal Veterinary and Agricultural University, Stigbøjlen 4, DK-1870 Frederiksberg C, Denmark
K. Buchmann*
Affiliation:
Department of Veterinary Microbiology, Section of Fish Diseases, Royal Veterinary and Agricultural University, Stigbøjlen 4, DK-1870 Frederiksberg C, Denmark
*
*Author for correspondence Fax: +45 35282711 E-mail: kub@kvl.dk

Abstract

Atlantic salmon, Salmo salar, is normally rather refractive to infection with the ectoparasitic monogenean Gyrodactylus derjavini but dexamethasone treatment of the host increases the susceptibility. The causative mechanisms were elucidated in this work. Groups of Atlantic salmon were treated by intra-peritoneal dexamethasone injections and subsequently infected with G. derjavini. It was shown that both the infection level and the mucous cell density of caudal and pelvic fins were affected by the treatment. Significantly higher mucous cell densities were found on infected and treated fish whereas non-infected and treated fish showed no significant elevation of cell density. This suggests that mucous cell discharge elicited by infection is inhibited by the drug. The association with elevated parasite counts in these fish can be explained either by decreased anti-parasitic mucus action or by parasite predilection for intact mucous cells.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2004

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