An assessment of the use of drug and non-drug interventions in the treatment ofIchthyophthirius multifiliisFouquet, 1876, a protozoan parasite of freshwater fish

Abstract

Infection by the ciliate protozoan Ichthyophthirius multifiliis Fouquet, 1876 causes significant economic losses in freshwater aquaculture worldwide. Following the ban on the use of malachite green for treating food fish, there has been extensive research aimed at identifying suitable replacements. In this paper we critically assess drug and non-drug interventions, which have been tested for use or have been employed against this parasite and evaluate possibilities for their application in farm systems. Current treatments include the administration of formaldehyde, sodium chloride (salt), copper sulphate and potassium permanganate. However, purportedly more environmentally friendly drugs such as humic acid, potassium ferrate (VI), bronopol and the peracetic acid-based products have recently been tested and represent promising alternatives. Further investigation, is required to optimize the treatments and to establish precise protocols in order to minimize the quantity of drug employed whilst ensuring the most efficacious performance. At the same time, there needs to be a greater emphasis placed on the non-drug aspects of management strategies, including the use of non-chemical interventions focusing on the removal of free-swimming stages and tomocysts of I. multifiliis from farm culture systems. Use of such strategies provides the hope of more environmentally friendly alternatives for the control of I. multifiliis infections.

The use of nitazoxanide against the pathogens Ichthyophthirius multifiliis and Aeromonas hydrophila in silver catfish (Rhamdia quelen)

“…This compound is effective in ornamental fish, but is currently listed as 'possibly carcinogenic to humans' by the World Health Organization (Picón-Camacho et al, 2011). The present experiment showed that infected fish survival was inversely proportional to the concentrations of NTZ.…”

“…Several drugs such as formaldehyde, sodium chloride (salt), copper sulphate and potassium permanganate are currently administered in the form of baths against Ich infections (see review of Picón-Camacho et al, 2011). In many countries it is no longer allowed to treat fish for human consumption with malachite green, due to its carcinogenic potential (Wohllebe et al, 2012).…”

Impact of Pseudomonas H6 surfactant on all external life cycle stages of the fish parasitic ciliate Ichthyophthirius multifiliis

“…However, the killing activity of PS against tomocysts appears to be higher when compared to other compounds. Tomocysts are equipped with a cyst wall and considered more resistant to the action of various disinfectants and chemicals (Ling, Wang, Wang, & Gong, ; Picon‐Camacho, Marcos‐Lopez, Bron, & Shinn, ; Song et al., ). It is therefore noteworthy that the Pseudomonas H6 surfactant in this study showed a strong effect on tomocysts, which suggests that the product will have a high potential for control of I. multifiliis in aquaculture facilities.…”

Evaluation of an antiparasitic compound extracted from Galla chinensis against fish parasite Ichthyophthirius multifiliis

“…However, there is no commercial vaccine available against the parasite. In the past several decades, 116 compounds were tested for treatment of Ich in vitro or in vivo (Picón-Camacho et al, 2012b), among them malachite green was the most effective parasiticide against Ich (Ruider et al, 1997) and frequently utilized to treat ichthyophthiriasis in fish farms. However, malachite green has been banned for use in food fish due to its carcinogenic and genotoxic effects on humans (Alderman, 1985;Wahli et al, 1993;Srivastava et al, 2004).…”