Light and electron microscope observations on presporogonic and sporogonic stages of Sphaerospora epinepheli (Myxosporea) in grouper (Epinephelus malabaricus).

Presporogonic (blood) stages of Sphaerospora epinepheli Supamattaya, Fischer-Scherl, Hoffmann, Boonyaratpalin, 1990 were observed in the circulating blood, sinus of kidney, glomerurar capillaries and liver arteries of grouper Epinephelus malabaricus. The earliest detectable stage was a primary cell with one secondary cell. After cell divisions, nine to 16 secondary cells were found in one primary cell. Ultrastructural examination revealed electron-dense bodies (118-145 nm) in the cytoplasm of primary cells. Sporogonic stages and spores were located in Bowman's space and in kidney tubule lumens. Electron micrographs revealed a similar pattern of spore development as described from other Sphaerospora spp. Kidneys infected with S. epinepheli showed highly vacuolated tubular epithelial cells and severely affected renal corpuscles.

[Reptiles as patients in veterinary practice]. / Reptilien als Patienten in der tierärztlichen Praxis.

Important diseases of reptiles are described with references to the diagnostic material and patients of the Institute of Zoology and Hydrobiology between 1984 and 1990. The commonest causes of mortality were pneumonia, parasites and poor husbandry. Problems associated with the increasing popularity of reptiles as pets, and appropriate treatments are discussed.

Immune complex-mediated glomerulonephritis associated with bacterial kidney disease in the rainbow trout (Oncorhynchus mykiss).

Rainbow trout (Oncorhynchus mykiss) developed a post-infectious chronic membranous glomerulonephritis 15 months after they had been experimentally infected with Renibacterium salmoninarum. Histologically, peritubular and periglomerular fibrosis, hypercellular glomeruli with occluded Bowman's space, and partial or complete adhesion to Bowman's capsule were constant features. Electron microscopy revealed thickened glomerular basement membranes with spikes accompanied by finely granular electron-dense deposits at the epithelial side and dense material in the mesangial matrix. Indirect immunofluorescence indicated linear immunoglobulin deposits along the glomerular basement membrane. The presence of R. salmoninarum was demonstrated by culture and by indirect immunofluorescence. Low serum hemagglutination-inhibiting antibody titers were demonstrated.

Sphaerospora epinepheli n. sp. (Myxosporea: Sphaerosporidae) observed in grouper (Epinephelus malabaricus).

Sphaerospora epinepheli n. sp. is described from grouper, Epinephelus malabaricus, in cage-cultured and wild fish collected from both coastal lines of southern Thailand. Subspherical to spherical spores and mono- or disporous pseudoplasmodia were observed in the lumen of kidney tubules. Pseudoplasmodia were round to elongate, size range 15.6-22.9 microns (length) x 8.4-21.6 microns (width). Spores were 7.8-10.0 microns (length) x 12.3-14.5 microns (thickness), and 7.0-9.5 microns (width) with two spherical polar capsules of equal size measuring 2.9-4.4 microns in diameter and containing polar filaments with six or seven windings. Two uninucleate sporoplasms showed iodine vacuoles. Blood stages, similar to C-blood protozoans observed from freshwater fish in Europe, were found from peripheral blood smears of grouper. Ultrastructural studies of blood stages showed a similar structure to unidentified mobile protozoans from the blood of carp. Electron dense bodies were observed in the cytoplasm of the primary cell blood stages. Infected proximal-tubular epithelial cells showed highly vacuolated cytoplasm and pycnotic nuclei.

[Myxozoa as parasites of the central nervous system of fishes]. / Myxozoa als Parasiten des Zentralnervensystems bei Fischen.

Myxosporea species in the central nervous system of fish and host-parasite interactions are described. Whereas parasites living in the nervous tissue itself do not induce clinical signs or host reactions, Myxosporea localized in neighbouring mesenchymatous tissues (blood vessels, cartilages, meninges) may induce disease of economic significance.

Morphological effects of acute and chronic atrazine exposure in rainbow trout (Oncorhynchus mykiss).

The effects of the herbicide atrazine (2-Chlor-4-ethyl-amino-6-isopropyl-amino-s-triazine) on the kidney of rainbow trout (Oncorhynchus mykiss) were studied by exposing them to sublethal concentrations of 1.4 and 2.8 mg atrazine per liter of water for 96 h (acute exposure) respectively to 5, 10, 20, 40, and 80 micrograms/L for a period of 28 days (chronic exposure). Alterations of the different components of renal corpuscles and of renal tubules, as well as an increase in cells with mitotic figures in renal hemopoietic interstitium were constant features at lower chronic (5, 10, 20, 40 micrograms/L) exposure; necrosis of endothelial cells and renal hemopoietic tissue were prominent at concentrations of 80 micrograms/L, and 1.4 and 2.8 mg/L atrazine.

Carp erythrodermatitis (CE) due to an Aeromonas hydrophila infection. Casuistic and experimental results.

In November 1987 high losses of carp (Cyprinus carpio) with the main symptom of skin ulcera were observed in a farm in northern Greece. Sixty-six isolates of bacteria, characterized mainly as Aeromonas hydrophila or Pseudomonas spp. could be isolated from lesions of diseased fish. Transmission experiments with these isolates using mirror carp showed that Aeromonas hydrophila strains induced identical clinical and pathological pictures after intra- or subcutaneous injection. Extracts of these Aeromonas hydrophila isolates, as well as a supernatant of culture bouillon were toxic for carp and mice, indicating the presence of endo- and exotoxins. The results prove that carp erythrodermatitis (CE) may be caused by different bacteria, mainly including A. hydrophila.

An outbreak of bucephalosis in fish of the Main river.

High losses due to metacercaria of Bucephalus polymorphus especially in cyprinids were observed in summer 1984 during a period of a sudden increase in water temperature. Pathology of diseased fish is described. Factors, such as eutrophication of the water system and overcrowding of distinct fish species, are discussed to be the main causes provoking outbreak of the parasitosis.

Light and electron microscopic studies on Myxobolus cotti el-Matbouli and Hoffmann, 1987 infecting the central nervous system of the bullhead (Cottus gobio).

Myxobolus cotti (Myxozoa: Myxosporea) is described as found in the central nervous system of the bullhead (Cottus gobio) caught in the Alpine lake Königssee and in a brook in the Bavarian Forest, Federal Republic of Germany (El-Matbouli and Hoffmann 1987). Aggregations of spores and polysporoblastic trophozoites compressed and replaced large areas of the white and grey matter of the brain and spinal cord. These aggregations may be surrounded by a thin, connective tissue capsule; in a few cases they were associated with loose infiltrates of glial cells. Neither conspicuous tissue reactions nor inflammatory responses were evident. No other organs were seen to be infected with M. cotti. Mature spores are oval, with a tapering anterior end, and the pyriform polar capsules are nearly equal in size. Fresh spores measured 8.9-15.1 microns in length (mean, 12.4 microns) and 8-12.4 microns in width (mean, 9.6 microns); polar capsules were 4.3-9 microns long (mean, 6.4 microns) and 2-3.8 microns wide (mean, 2.9 microns). Light microscopy, the ultrastructure of pansporoblasts, sporogenesis and mature spores are described.