Antiprotozoals effective in vitro against the scuticociliate fish pathogen Philasterides dicentrarchi.
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 activity against 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-(2'-hydroxy-5'-chloro-benzoyl) 2-chloro-4-nitroaniline, furaltadone, doxycycline hyclate, formalin, albendazole, carnidazole, pyrimethamine, quinacrine hydrochloride and quinine sulfate. Administration in filtered seawater 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 these findings, we discuss the potential utility of chemotherapy as a strategy for the control of scuticociliatosis in farmed turbot and sea bass.
Iglesias
R
R
Laboratorio de Parasitología, Instituto de Investigación y Análisis Alimentarios, Universidad de Santiago de Compostela, Spain.
Paramá
A
A
Alvarez
M F
MF
Leiro
J
J
Sanmartín
M L
ML
D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001492:Bass / Q000469:parasitology*; D016798:Ciliophora / Q000187:drug effects* / Q000254:growth & development; D016770:Ciliophora Infections / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D005393:Fish Diseases / Q000188:drug therapy* / Q000469:parasitology; D005398:Fisheries; D005412:Flatfishes / Q000469:parasitology*; D066298:In Vitro Techniques; D016896:Treatment Outcome
D000981:Antiprotozoal Agents