A broad spectrum antiparasitic effect of nitazoxanide: an important advancement

Background: Parasitic infection has grown to be one of the most significant causes of morbidity and mortality worldwide. Nitazoxanide, a new antiparasitic drug, is believed to have a remarkable effect. This work aimed to study the in-vitro effects of nitazoxanide on Echinococcus granulosus, as an example of helminthic infection, and Blastocystis spp., as an example of protozoal infection, compared with the standard drugs in use. Materials and methods: Hydatid protoscoleces and Blastocystis spp. were isolated and cultivated each on its specific medium. Nitazoxanide and standard drugs (albendazole for hydatid or metronidazole for Blastocystis spp.), or a combination of nitazoxanide and the standard drug for each were added to separate cultures, and parasite motility and viability were assessed. Furthermore, electron microscopic study for both parasites was carried out. Results: The results showed a directly proportional relationship between number of dead protoscoleces and the tested nitazoxanide concentration; 50% of protoscoleces were killed (LD50) at 6 h incubation with 15 μg/ml of nitazoxanide, compared with LD50 of albendazole that was 30 μg/ml at 6 h. For Blastocystis spp., LD50 was 2 μg/ml after 48 h, whereas that for metronidazole was 10 μg/ml at the same culture duration. On combining nitazoxanide and the standard drugs, it showed variable effect, especially against Blastocystis spp. Conclusion: These advantageous results toward nitazoxanide may allow trying the drug for both helminthic and protozoal infections.