Efficacy of various chemotherapeutic agents on the growth of Spironucleus vortens, an intestinal parasite of the freshwater angelfish

Abstract

Seven chemotherapeutic agents (dimetridazole, metronidazole, pyrimethamine, albendazole, fenbendazole, mebendazole and magnesium sulfate) were examined for growth inhibition on the cultivation of Spironucleus vortens. Dimetridazole and metronidazole were effective in inhibiting the parasite's growth. At concentrations of 1 μg ml-1 or higher, both dramatically decreased numbers of parasites. At 24 h exposure, 33% of parasites were inhibited when exposed to dimetridazole or metronidazole at concentrations of 2 and 4 μg ml-1, respectively. Dimetridazole at 4 χ ml-1 or higher concentrations decreased the number of organisms to 506/0 or less after 48 h exposure. During the same period of time, the numbers of parasites decreased to 50% or less when exposed to metronidazole at 6 μg ml-1 or higher. Pyrimethamine at concentrations of 1 to 10 μg ml-1 was not effective in inhibiting the parasite's growth. Albendazole and fenbendazole at concentrations of 0.1 and 0.5 μg ml-1 were similar in inhibiting the growth of the organism. Both compounds suppressed parasite growth at concentratiOnS of 1.0 μg ml-1 or higher after 24 h exposure. Mebendazole inhibited the parasite's growth at concentrations of 0.5 μg ml-1 or higher. At 72 h exposure, 45 to 50% of the parasites were inhibited when exposed to mebendazole at concentrations higher than 0.5 μg ml-1. Magnesium sulfate at concentrations of 70 mg ml-1 or higher also suppressed the growth of parasites after 24 h exposure. These results indicate that dimetridazole, metronidazole and mebendazole are the most effective chemotherapeutic agents in vitro at inhibiting the growth of S. vortens.