Praziquantel (Droncit) is effective against diplostomosis of grasscarp Ctenopharyngodon idella and silver carp Hypophthalmichthys molitrix

In laboratory experiments praziquantel (Droncit) effectively destroyed metacercariae of Diplostomum spathaceum (s. l.) parasitizing the eye lens of grasscarp Ctenopharyngodon idella and silver carp Hypophthalmichthys molitrix. A single treatment with Droncit fed at a dose of 330 mg kg^-1 body mass showed 100% efficacy against metacercariae parasitizing grasscarp. A similar, complete parasiticidal efficacy was achieved when infected grasscarp and silver carp specimens were exposed to a solution containing 1 mg praziquantel l^-1 for at least 90 h. Using shorter exposures (20 min to 1 h) but elevated praziquantel doses (10 to 100 mg l^-1), some parasites survived but even here the intensity effect reached 67 to 97%

Goussia trichogasteri n. sp. (Apicomplexa: Eimenidae) infecting the aquarium-cultured golden gourami Trichogaster trichopterus trichopterus

Goussia trichogasteri n. sp. is described from the gut of the aquarium fish Trichogaster trichopterus trichopterus. Gamogonic stages develop epicellularly in the gut epithelium. Oocysts are shed in early stage of sporulation. Sporulated oocysts are characterised by having centrally locating oocyst residua. The whole development of the species takes place in the aquarium

Host reaction in paratenic fish hosts against 3rd stage larvae of Anguillicola crassus

Many fish species of Lake Balaton (Hungary) serve as paratenic hosts for the 3rd stage larvae of the eel parasite Anguillicola crassus. The incidence oi different phases of the host reaction varies with paratenic fish host but its nature is basically the same. The appearance of mononuclear cells around the larvae migrating in the tissues or in the abdominal cavity is regarded as a sign of cellular host reaction. The cells adhering to the surface of the larvae gradually assume an epithelioid shape and form a granuloma. With the advancement of the process the larvae and the epithelioid cells surrounding them undergo necrosis, and the granuloma becomes surrounded by a connective tissue capsule. In more chronic cases, the inside of the parasitic nodule surrounded by several layers of connective tissue is filled out by amorphous tissue and parasite debris. In the 'suitable paratenic hosts' Anguillicola sp. larvae not affected by the host's cellular reaction outnumber those affected by it, whereas in the 'less suitable paratenic hosts' the cellular reaction very rapidly forces the larvae into foci and destroys them

Pathological and histopatnotogical studies of the swimbladder of eels Anguilla anguitla infected by Angutlticpta crassus (Nemafoda: Dracuncuioidea)

The swimbladder lesions produced by Anguillicola crassus (Nematoda) infection, causing mass mortality among eels in Lake Balaton (Hungary) were studied by histological methods. In the initial phase of infection, no severe changes developed in the swimbladder wall despite the presence and intensive blood-sucking activity of worms that filled the lumen of the swimbladder. After disruption of the worms and primarily because of repeated reinfection by larvae, however, the wall of the swimblaader markedly thickened and showed degenerative, inflammatory and proliferative changes. Acute processes were characterized by epithelial hyperplasia and hyperaemia of the swimbladder wall. In cases of chronic swimbladder inflammation, oedema and hyperplasia of tissues of the tunica propria, submucosa and serosa could be observed, as well as granulomatoid infiltration by mononuclear cells and fibrinoid degeneration around the larvae

Fumagillin, an efficacious drug against renal sphaerosporosis of the common carp Cyprinus carpio

At present no reliable and efficacious drugs are available for treating fish diseases caused by myxosporeans. By feeding Fumagillin DCH salt in the diet, the authors achieved very promising results in controlling renal sphaerosporosis, one of the commonest myxosporean parasitoses of common carp Cyprinus carpio. Intraperitoneal injection of Sphaerospora renicola stages developing in the swimbladder produced sphaerosporosis only in control groups, whereas in fish consuming 0.1 % fumagillin no infection developed. Farm-pond experiments also gave promising results: in fumagillintreated common carp fry a much milder sphaerosporosis developed, both in prevalence and intensity, than in control fish

Radiodiagnostic method for studying the dynamics of Anguillicola crassus (Nematoda: Dracunculoidea) infection and pathological status of the swimbladder in Lake Balaton eels

Swimbladder changes resulting from Anguillicola crassus infection of the European eel Anguilla anguilla have been the subject of several studies reported in the literature. These investigations, however, studied exclusively the status of infection at a given point in time and did not deal with changes in swimbladder infection in eels suffering from anguillicolosis over a period of time. In this study, A. crassus-induced pathological changes were monitored in 78 eels naturally infected in Lake Balaton and subsequently kept in the laboratory, thus excluding the possibility of further infection. During the 3 mo study, the status of the swimbladder was checked by radiographic examination on 4 occasions. At the end of the study the eels were dissected and the gross pathological changes in the swimbladders were compared with the radiographic findings. As compared to their starting condition, by the end of the study the pathological status of the swimbladder had deteriorated in 55 % and remained the same in 37 % of the cases. Tendency to improvement (1 %) and variable findings (7 %) were recorded in a low percentage of cases only. With the help of the radiographs presented, the dynamics of A. crassus infection and of changes in the swimbladder of individual eel specimens can be monitored easily

Description of a new actinosporean type from South African freshwater

The 1st report on actinospores described these organisms as parasites related to myxosporeans. For a long time this group of parasites was believed to represent an independent taxonomic entity. Research on actinosporeans became more intensive after it was shown that they corresponded to the intraoligochaete developmental stages of fish-parasitic myxosporeans. The relevant research includes earlier surveys, as well as studies of actinospore infection of oligochaetes in natural waters and fish farms in connection with the life cycle of myxosporeans. Relatively little data areavailable on myxosporean infections of African freshwater fishes and only a single paper appeared in Africa on their actinosporean alternative stages infecting oligochaetes. In September 2003, actinospore infection of oligochaetes collected from the mud of 2 freshwater biotopes in South Africa was studied. Using the ‘cell-well plate method’, a new aurantiactinomyxon type was found in 1.1 % of the examined Branchiura sowerbyi oligochaete specimens from Rietvlei River northwards to Johannesburg, Gauteng. In 1.5 % of Branchiura sowerbyi collected in a pond (Padda Dam), near the Rand Afrikaans University, Johannesburg, the same aurantiactinomyxon type was found. Infected oligochaetes were found only after collection, no actinosporean release was recorded in Branchiura specimens kept alive for several weeks. Actinospore infection showed high intensity in oligochaetes in both positive cases. Until now, no actinosporean stages of myxosporeans have been described from South Africa. The aurantiactinospore type presented in this paper differs from the already known types described in the special literature

Intraoligochaete development of Myxobolus intimus (Myxosporea: Myxobolidae), a gill myxosporean of the roach (Rutilus rutilus)

The infection with Myxobolus intimus Zaika, 1965 in the gills of the roach Rutilus rutilus (L.) from Lake Balaton was recorded in 28 out of the 39 fish examined. Developing and mature plasmodia were detected on the gills exclusively in the spring. The Myxobolus intimus infection was found only in 2- to 3-year-old fish. In histological sections, young plasmodia were found in capillaries of the secondary lamellae. More mature, round plasmodia 0.4-0.6 mm in diameter, deformed the respiratory lamellae. The intraoligochacte development of M. intimus was studied in experimentally infected oligochaetes. In two experiments, uninfected Tubifex tubifex Muller and Limnodrilus hoffmeisteri (Claparede) were exposed to mature myxospores of M. intimus. In both experiments, typical triactinospores developed in T. tubifex specimens but no infection was found in L. hoffmeisteri. In semithin sections, developmental stages, pansporocysts and actinospores, were found within the proliferated gut epithelium of T. tubifex. Triactinospores were first released from oligochaetes 37 and 58 days after initial exposure in the two experiments, respectively. Each triactinospore had three pyriform polar capsules and a cylindrical sporoplasm with 32 secondary cells. The spore body joined the 3 caudal projections with a moderately long style

A survey of coccidian infection (Apicomplexa: Eimeriidaea) of freshwater fish in South Africa

Fish coccidia, especially Goussia and Eimeria spp., are common and frequent parasites of fish. The majority of the known species has been described from the Eurasian continent. Little is known, however, of the coccidian infections of South African freshwater fish. In September 2003, 77 specimens from 7 freshwater fish species were harvested at 4 sites from rivers and ponds in the Gauteng, North West and Limpopo provinces in South Africa. The fish were surveyed for coccidian infections. Two fish species were infected with apicomplexans belonging to Goussia. In banded tilapia (Tilapia sparrmanii Smith) unsporulated oocysts of Goussia vanasi Landsberg and Paperna, 1987 were found. These sporulated in tap water within 24 hours. Another species in the gut of the chubbyhead barb (Barbus anoplusWeber) harboured sporulated oocysts in the faeces and in the intestinal epithelium. The latter species has been described as Goussia anopli. This short survey suggests that more thorough studies might reveal the occurrence of further coccidian species in South African fishes

Infection of cultured and freshwater fishes with monogeneans in Syria

During a survey made in 2004 and 2005 in Syrian fish farms of the Orontes valley and on natural water fishes harvested in the Orontes River and in Lake Assad (a water reservoir of the Euphrates River), 145 specimens of fish belonging to 15 fish species were examined for monogenean infections. Eleven monogenean species (8 Dactylogyrus spp., 1 Silurodiscoides sp. and 2 Cychlidogyrus spp.) were found in the gills. Monogeneans infecting farm-cultured fishes were the same as those commonly occurring in cyprinids (Dactylogyrus anchoratus, D. extensus, D. lamellatus) and filapia (Cychlidogyrus tilapiae, C. arthracan thus) cultured in Europe and in tropical countries. Among monogeneans found in fishes of natural waters, typical representatives of the Tigris-Euphrates Basin (Dactylogyrus carassobarbi, D. holciki) and species common in the Holoarctic zoogeographical zone (D. alatus, D. carpathicus, D. distinguendus and Silurodiscoides vistulensis) were equally found