DAO 62:97-102 (2004)  -  doi:10.3354/dao062097

In vitro efficacy of new antiprotozoals against Philasterides dicentrarchi (Ciliophora, Scuticociliatida)

A. Paramá1, R. Iglesias2, F. Álvarez1, J. M. Leiro1, J. M. Quintela3, C. Peinador3, L. González3, R. Riguera4, M. L. Sanmartín1,*

1Laboratorio de Parasitología, Instituto de Investigación y Análisis Alimentarios, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
2Área de Parasitología, Departamento de Biología Funcional y Ciencias de la Salud, Facultad de Ciencias, Campus Lagoas/Marcosende s/n, Universidad de Vigo, 36200 Vigo, Spain
3Departamento de Química Fundamental e Industrial, Facultad de Ciencias, Universidad de La Coruña, 15701 La Coruña, Spain
4Departamento de Química Orgánica, Facultad de Química, Instituto de Acuicultura, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
*Corresponding author. Email:

ABSTRACT: Philasterides dicentrarchi is a histiophagous ciliate that causes severe losses in turbot and sea bass farming. This study investigated the in vitro efficacy against P. dicentrarchi of 85 newly synthesized compounds and 12 commercial compounds, of which 2 are fluoroquinolones (norfloxacine and lomefloxacine) with known antibacterial activity. Seventeen of the newly synthesized compounds (2 naphthyridines, 2 pyridothienodiazines and 13 pyridothienotriazines) and the fluoroquinolone norfloxacin showed good activity. The most promising compound was the pyridothienotriazine 12k, with activity similar to that of the salicylanilides niclosamide and oxiclozanide (MLC 0.8 mg l–1 in PBS, 1.5 mg l–1 in seawater; MLC = minimum 24 h lethal concentration).


KEY WORDS: Philasterides dicentrarchi · Turbot · Scuticociliatosis · In vitro assay · Naphthyridines · Pyridothienotriazines · Pyridothienodiazines


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