Scientia Parasitologica, 2007, 1, 91-98 The prevalence, ichtyopathological significance and control measures of Gyrodactylus specimens in fishes from the waters of Banat region C.D. COJOCARU Direc Ńia Sanitar ă Veterinar ă şi pentru Siguran Ńa Alimentelor Timi ş (State Sanitary Veterinary and Food Safety Directorate of Timi ş county), Str. Surorile Martir Caceu nr. 4, 300585 – Timi şoara, România, e-mail: [email protected] ABSTRACT. In Banat`s waters was recorded two species of Gyrodactylus : G. elegans from the gills of bream (Abramis brama danubii) , and also in carp (Cyprinus carpio), on gills and skin, and G. medius , found on body surface and gills of the young goldfish (Carassius auratus auratus) . A varieties of this two species are discussed. G. medius is a highly pathogenic species for young goldfish and G.elegans can produced important outbreaks and damages in carp culture. Formalin can be useful for the treatment of gyrodactylosis in goldfish, but it is forbidden in carp culture. The surveillance of carp and goldfish gyrodactilosis is necessary, and they must be included by the O.I.E. list of fish diseases like salmonid gyrodactylosis. Key words: G. medius, goldfish gyrodactylosis, G. elegans, carp gyrodactylosis. Introduction Gyrodactylosis is an important ectoparasitosis of the fish, especially in aquaculture. Among the The very most of monogeneans (over 1500 parasitical diseases of fishes, only salmonid species) are fish ectoparasites, which are found gyrodactylosis with Gyrodactylus salaris is on the skin and gills. A few species are met in comprised in the O.I.E. list of fish diseases, amphibians, reptiles, cephalopods and because this little monogenean can produce mammalians (in the eye of Hippopotamus ). Most significant looses and damages in the field of species are found in marine fish. salmonids rearing, a very profitable activity. A high prevalence of these parasites is present in Acording to Boeger and col. (1992), the wild fish, but they do not generate too serious taxonomical position of Gyrodactylus is: diseases. Some species are strongly pathogenic, supraregnum Eucarya , regnum Animalia , branch and when they enter fish farms, they cause Metazoa, Eumetazoa, Coelomata , subregnum important mortalities, decreases of growing Bilateralia , branch Protostomia , infraregnum rhythm and economic losses. The symptoms and Platyzoa , phyllum Plathelminthes , subphylum lesions are not very specific: increasing of gill Neodermata , infraphyllum Cercomeromorpha , and skin mucus secretion, equimoses, class Monogena, subclass Monopisthocotylea, ulcerations, hyperplasia and sometimes necrosis. order Gyrodactylidea, suborder Gyrodactylinea , Among the monogenosis with ichtyopathological family Gyrodactylidae , subfamily significance, we mention: carp dactylogyrosis, Gyrodactylinae , genera Gyrodactylus . ancyrocephalosis of tropical aquarium fish, sheat Gyrodactylus specimens are very small worms fish silurodiscoidosis, sturgeon nitschiosis, (0,5-1,2/0,1-0,3 mm), translucent, viviparous and salmonid and pike tetraonchosis, salmonid hermaphrodite; In the body of adults we can see gyrodactylosis, salmonid discocotilosis and one young worm and this containing another diplozoonosis (monogenosis with insufficient worm. Very often, this „grandchild” contains elucidated ichtyopathological significance). another embryon (Kinkelin and col., 1985, Ghittino, 1986, van Duijn, 1973, Schäperclaus, 91 1979, Roberts, 1989). They have an elliptical Turcesc and Banloc), S.C. Coscerco S.R.L. shaped body, without eye spots, but with two Topolov ăŃ u Mare, S.C. Santim S.A. Sânandrei, conical projection at the anterior end which bear the Pi şchia dam, the pools from S ăcălaz, Calacea cephalic glands, secreting a thick, sticky liquid and Ni Ńchidorf, the irrigation channel Giroc - (Elena Roman-Chiriac, 1960, van Duijn, 1973,). Chi şoda - Mo şni Ńa Nou ă, the puddle from Intestinal ceca terminating blind near posterior Ghiroda. A few specimens of young goldfish end of body proper. At the posterior end of body, provided from an aquarium and a basin built in a a strong atachement organ is situed. This organ is yard. The parents of young goldfish have been disc-shaped, has two large central hooks imported from Thailand. Fishes have been (anchors) supported by a dorsal and ventral bar carried out in the Aquatic Pathology Laboratory, and surrounded by a ring of 16 marginal within the State Sanitary Veterinary Laboratory hooklets. The atachent organ (opisthaptor) are of Timi ş county, using also own material very mobile and the morphometry and resources. So, we have designated some morphology of the opisthaptoral pieces has absolutely necessary endowments, like the taxonomically significance (Yamaguti, 1967, macrophotographic stall and the Euzeby, 1986, Margolis and Beverley-Burton, ichtyoparasitological case. 1984). From Malmberg (cited from Euzeby, 1986), the excretory system differ from each Work methods aimed especially the following other specimens, and this taxonomical feature is objectives: useful for taxonomy. So that, after the morphology of excretory system, exist a few - the accomplishment of a monograph subgenera of Gyrodactylus : Mesonefrotus, concerning the Gyrodactylus species from the Metanefrotus, Paranefrotus, Neonefrotus and fishes of Banat region, there being not any such Limnonefrotus , which are divided in groups systemic studies at the moment; acording with the morphology of cyrus and opisthaptoral sclerites. - the accomplishment of some studies regarding the epidemiology of the Gyrodactylus from the Over 300 species of Gyrodactylus are recorded Banat; from freshwater fishes. (Bauer, 1985, Beverley- Burton, 1984, Ergens and Lom, 1970). - the field investigation of some disease episodes in fish, in order to get a general view upon the The dead worms are very quickly disintegrate. ichtyopathological importance of the For this reason, in order to confirm Gyrodactylus species from the fishes of Banat gyrodactylosis, it is essential to send to the region, being aware of the fact ichtyoparasitoses` laboratory only alive fish in water where they epidemiological, pathological and control aspects live, exceptionally in formaldehyde 4% or cannot be considered separately from the other ethanol 70%. The study upon opistaphor`s ichtyopathological components (ecological, morphology and morphometry after the virusologic and bacteriological), taking also into clarification with ammonium-picrate-glycerine account the human, legislative and decisional (APG) – the Malmberg’s method, usable for all aspects; monogeneans, or the genetic analyses – PCR, applicable especially for Gyrodactylus species in - the basic component of our researches is Salmonidae , are the methods used at this represented by the problems related to a correctly moment. and earlier diagnosis of gyrodactylosis, this representing the key for the adoption of control Material and methods measures; During the years 2000-2005, we have examined - the adoption of a viable strategy regarding the 2331 fish samples and investigated 47 fish ichtyoparasitological control of gyrodactylosis. species, taken from the following waters: the From theoretical and also practical reasons, we Danube stream, the rivers: Timi ş, Pog ăni ş, considered essential to know the prevalence of Bistra, Bega, Nera, Cerna, Cara ş, Bârzava, the Gyrodactylus specimens in natural waters whose lakes: V ăliug and Surduc, the trout farms V ăliug ichtyopathological importance is not very and Române şti, the cyprinicol units: S.C. significant. We can’t exclude automatically the Pescotim S.A. (farms in Timi şoara, Saco şu 92 ichtyopathological implications of a species just from the old fish, but they can’t produce because we have not studied it enough. outbreaks at this age. Identification of the specia: a little monogenean (0,2-0,3 mm x 0,06 mm). The diagnostic method of Gyrodactylus species Thiny and relatively straight central hooks with was stereomicroscopic and microscopic 30-40 µm total length. The point of central hooks examination, using ammonium-picrate-glycerine 20 µm. Total length of marginal hooks; 20 µm. solution (APG) - the Malmberg’s fixation-, Dorsal bar slowly curved, thiny, without relying upon the opisthaptor`s morphology and membrane, about 17 µm. Ventral bar, 20 µm x 4 morphometry. For parasitological examination µm. Comments: about the opisthaptoral features the fishes were carried on in water where they this species resembling whith G. carassi , but this living. After the microscopical examination of species are more larger (until 1mm), and the scraping from gills and skin we make a ventral bar is more bigger. The anchor shaft of stereomicroscopical examination of the the the specimens founded by us is straighter then surface of the fish body. The sediment of water the G. medius type specimens; for this reason the using at fish transport and for rinsed the gills and specimens recorded from goldfish can be a fish body surface was examined too. If the subspecia of G. medius . Specimens resembling worms are observed by their movements, they with the specimens of „elegans group”, but these must be transferred to a slide in a drop of water. species are more larger, except some species A cover slip is gently placed on a top and a small from aquarium fish, but not Carassius auratus drop of APG is added to the edge of cover-slip. auratus . Very similar is G. elegans kobayashii Four drop of nail-polish should be added to each (sin. e. yamaguti) , recorded in Japan from the corner of the cover-slip