Effects of orally administered chemotherapeutics (quinine, salinomycin) against Henneguya sp. Thelohán, 1892 (Myxozoa: Myxobolidae), a gill parasite in the tapir fish Gnathonemus petersii Günther, 1862 (Teleostei)

Abstract

When given orally, quinine or salinomycin cause irreversible damage to the plasmodial developmental stages of Henneguya sp., a gill parasite in the tapir fish Gnathonemus petersii. Naturally infected tapir fish measured 75-169 mm in total length and their total weight ranged over 4.3-11.7 g. The fish bore 7-77 plasmodia in their gill arches. Medicinal food containing either quinine (5 g/1000 g food) or salinomycin (0.075 g/1000 g food) was given once a day to naturally infected fish in a food chain via water fleas ( Daphnia spp) for a period of 3, 6, or 9 days. From the monitored feeding of the tapir fish and weight determinations of the water fleas, it was calculated that gross uptake was 18.5 micro g/kg body weight fish daily for pure salinomycin and was 1.25 mg/kg body weight daily for quinine. After the end of the experiments, the fish were sacrificed and the plasmodia were carefully prepared from the gill arches and processed for transmission electron microscopy. As seen by ultrastructure investigations, for both substances the grade of damage in the parasites correlated positively with the period of application. When quinine was given for a 3-day period, the trophozoite ecto- and endoplasm exerted numerous vacuoles, caused by the drug, and the presporogonous and the pansporoblastic stages were malformed. Following a 6-day period, numerous abortive polar capsules were found in the trophozoite cytoplasm. To a large extent, the limiting membranes of the polaroblasts and valvogenic cells were destroyed. In addition, deep clefts between the polaroblasts, the valvogenic cells and between the two sporoblasts were observed. Following a 9-day treatment, all damage increased and, in addition, generative cells and two-cell stages were no longer detectable. As a first sign for the effects of salinomycin, following a 3-day treatment, a shrinking of the whole plasmodia occurred and the sutures in the pansporoblasts were enlarged. The polar capsules were malformed and the zonar structures of the polar filament were no longer detectable. The sporoplasmosomes were more electron-pale than those of the control samples. After a 9-day treatment, the pansporoblasts were completely destroyed. Under the experimental conditions chosen, both compounds were very well tolerated by the fishes.

Histology, ultrastructure and prevalence of Henneguya piaractus (Myxosporea) infecting the gills of Piaractus mesopotamicus (Characidae) cultivated in Brazil

“…The plasmodial wall of Henneguya piaractus consisted of a single membrane, as in other myxosporean species (Current & Janovy 1978, Current 1979, Hallett & Diamant 2001, Dohole et al 2002, and contained pinocytic canals that extended into the plasmodial ectoplasm, as also seen in several other Henneguya species (Current & Janovy 1976, Current 1979, Rocha et al 1992, Hallett & Diamant 2001, Azevedo & Matos 2002, El-Mansy & Bashtar 2002. However, there was no coat, nor was the wall surrounded by a capsule of collagen fibres.…”

The Impact of a Successful Anti-Myxosporean Treatment on the Phagocyte Functions of Juvenile and Adult Sparus Aurata L

“…It has a strongactivity against many microorganisms including coccidia, since it causes pellicula shrinking, cytopla sm vacuolisation and mitochondria destruction (29) . According to previous reports, salinomycin given orally in the tapir fish Gnathomenus petersii naturally infected with Henneguya sp ., a gill parasite caused irreversible damage to plasmodial developmental stages of the parasite (30). On' the other hand, amprolium is a structural analogue of thiamine causing a competitive inhibition of thiamine utilization by the parasites.…”

Efficacy of quinine against ichthyophthiriasis in common carp Cyprinus carpio

“…Several studies have been performed to evaluate the efficacy of quinine against fish parasites, and an effect was shown for Henneguya sp. (Dohle et al 2002) and Loma salmonae (Speare et al 1998). Schäperclaus (1954) described the use of quinine as a bath treatment against ichthyophthiriasis, and Schmahl et al (1996) showed the efficacy of dietary quinine against this disease in ornamental fish.…”