Antiprotozoals effective in vitro against the scuticociliate fish pathogen Philasterides dicentrarchi

[摘要] ABSTRACT: The histophagous ciliate Philasterides dicentrarchi causes fatal scuticociliatosis in farmed turbot Scophthalmus maximus and sea bass Dicentrarchus labrax. The present study screened 52 candidate antiprotozoals for activityagainst this pathogen in vitro. Of these compounds, 14 were effective (i.e. killed all ciliates within a 24 h assay period). In descending order of efficacy (minimum lethal concentration 100 to 0.8 ppm), these were niclosamide, oxyclozanide,bithionol sulfoxide, toltrazuril, n (2¹-hydroxy-5¹-chloro-benzoyl) 2-chloro-4-nitroaniline, furaltadone, doxycycline hyclate, formalin, albendazole, carnidazole, pyrimethamine, quinacrine hydrochloride and quinine sulfate. Administration in filteredseawater rather than phosphate-buffered saline inactivated doxycycline hyclate and albendazole, and markedly reduced that of bithionol sulfoxide and toltrazuril, suggesting that these compounds may not be effective in bath administration. In view of thesefindings, we discuss the potential utility of chemotherapy as a strategy for the control of scuticociliatosis in farmed turbot and sea bass.

[学科分类] 生物科学（综合）

[关键词] Turbot;Scuticociliatosis;Philasterides dicentrarchi;Chemotherapy;In vitro assay