Ichthyophthirius multifiliis is a widespread parasite on farmed fish and causes white spot disease or curculio. It attaches to the skin and gills of fish, feeding on these cells. This leads to tissue damage, disturbances in electrolyte balance, and eventual death of the fish. Since this parasite can cause great losses in fish farms, efficient treatment is of great importance. At present, however, there are no suitable treatment methods.
Recently, two publications by Chinese scientists (Liu et al. 2017a, b) appeared indicating that in grass carp, Ichthyophthirius multifiliis infestation can be successfully treated with turmeric extract. Turmeric or yellow ginger is a ginger plant found in South Asia that is believed to have anti-inflammatory effects.
To find out whether turmeric extract is effective for the treatment of Ichthyophthirius multifiliis in salmonids, we conducted several tests. Parasites isolated from fish could be effectively killed with turmeric as described in the cited publications. However, treatment attempts of salmonids infested with Ichthyophthirius multifilis with turmeric were ineffective. Parasite infestation could not be reduced. From our experiments, it appears that the published method is unsuitable for treating Ichthyophthirius multifilis in troutids. It is possible that turmeric may reduce the symptoms of parasite infestation due to its anti-inflammatory properties.
Literature
Liu Y., Zhang Q., Xu D., Fu Y., Lin D., Zhou S., Li J. (2017a). Antiparasitic efficacy of curcumin from Curcuma longa against Ichthyophthirius multifiliis in grass carp. Veterinary Parasitology, 236, 128-136. https://doi.org/10.1016/j.vetpar.2017.02.011.
Liu Y., Zhang Q., Xu D., Fu Y., Lin D., Zhou S. (2017b). Antiparasitic efficacy of commercial curcumin against Ichthyophthirius multifiliis in grass carp (Ctenopharyngodon idellus), Aquaculture, 480, 65-70. https://doi.org/10.1016/j.aquaculture.2017.07.041.