The Gyrodactylidae fauna of rainbow trout Oncorhynchus mykiss Walbaum 1792 in the Rogg breeding pound in Bavaria, Germany.

In July 2005, 107 rainbow trout in age 1+ from a salmonid farm in Southern Germany situated in the southern tributary area of the Danube river were examined. The aim of this study was to determine the gyrodactylid species found on rainbow trout and to identify their location on the host's body. In total, 291 specimens from genus Gyrodactylus were collected. The most abundantly occurring species was Gyrodactylus truttae (181 specimens), whilst the others were less abundant. For the first time in Germany, Gyrodactylus teuchis and Gyrodactylus derjavinoides on rainbow trout were found. Most parasites occurred on the pectoral and ventral fins. Few specimens were found on the anal or caudal fins, in the oral cavity or on the gills. The only uninfected place was the nasal cavity.

Detection of genomic DNA of the crayfish plague fungus Aphanomyces astaci (Oomycete) in clinical samples by PCR.

A diagnostic procedure, based on a polymerase chain reaction method (PCR) was developed to detect infection of crayfish with the Oomycete Aphanomyces astaci. A set of oligonucleotide primers was designed to specifically amplify A. astaci DNA in the ITS region surrounding the 5.8S rDNA gene. The PCR amplifies a 115bp amplicon. The specificity of the primers was demonstrated by testing on 27 A. astaci strains and against 20 non-A. astaci Oomycetes and 5 fungal species. Most of the non-A. astaci Oomycete or fungal species included in the study are either known parasites of freshwater crayfish cuticle or can be found in their natural environment. Specificity was also tested against crayfish tissue and some known parasites and bacteria infecting crayfish. A protocol for the extraction of A. astaci DNA from infected crayfish tissue was developed. The optimised method allows the detection of two genome equivalents of purified A. astaci genomic DNA. The method was tested on noble crayfish (Astacus astacus), artificially infected with A. astaci. Detection of A. astaci was possible at the very first time of sampling, which was 2 days after the beginning of spore exposure.

[Fresh water fish farming--fishing ponds and "cesarean section"]. / Süsswasserfischproduktion--Angelteiche und "Kaiserschnitt".

Present knowledge on the capability of fish to feel pain and of suffering is presented. According to these data it has to be supposed, that fish are able to feel fish. Suffering and damage can be proven by biochemistry and morphology. Under these aspects, angling ponds and cesarean section in sturgeon have to be regarded as a violation of the German animal welfare act.

Seasonal occurrence of actinosporeans (Myxozoa) and oligochaetes (Annelida) at a trout hatchery in Bavaria, Germany.

A systematic inventory of actinosporeans and oligochaetes conducted over 3 years at a trout fish farm in Bavaria, Germany, allowed the identification of 12 actinosporeans from five collective groups: four Triactinomyxon (Triactinomyxon nov. types 1-4), two Raabeia (Raabeia nov. types 1, 2), two Echinactinomyxon ( E. radiatum, Echinactinomyxon nov. type 1), two Aurantiactinomyxon ( A. pavinsis, Aurantiactinomyxon nov. type 1) and two Neoactinomyxum (Neoactinomyxum nov. types 1, 2). Nine forms are novel but can be placed within existing collective groups. All 12 forms were detected in the laboratory in aquarium water associated with farm sediment. However, only four of these could be linked with an oligochaete host. Three families of oligochaetes were identified from the sediment: Tubificidae, represented by eight species, Lumbriculidae with one species and Naididae with two species. Only tubificid oligochaetes were found to host actinosporeans.

Early developmental stages of two actinosporeans, Raabeia and Aurantiactinomyxon (Myxozoa), as detected by light and electron microscopy.

The development of actinosporeans in their oligochaete host proceeding pansporocyst formation is relatively well documented, however, phases preceding it are not as well known. The initial stages in the development of two actinosporeans, Raabeia type 1 of Oumouna et al. [Parasitol. Res. 2002] and Aurantiactinomyxon pavinsis (Ormières, 1968) Marquès [Languedoc, Universite des Sciences et Techniques, Dissertation, 1984] from schizogony to gametogony and sporogony are described. Both actinosporeans begin their development as multinucleate stages near the basal lamina of the oligochaete intestine. Proximal to these stages and between the host epithelium cells are uninucleate cells whose nuclei divide to produce binucleate cells. These divide mitotically to produce cells with four nuclei which then undergo plasmotomy to yield a tetracellular stage and the first phase in pansporocyst formation. From the uninucleate stage to the tetranucleate stage, the cell membrane of the parasite is associated closely via finger-like projections with the intestinal epithelial and glandular cells of the host.

[Pain and suffering in fish]. / Schmerzen und Leiden bei Fischen.

The question on the capability of fish to feel pain and of suffering are still subject of discussion nowadays. In the article presented, the information available in the literature to date is summarised. Based on this knowledge, the conclusion is drawn that fish are capable of feeling pain and that they are able to suffer in the sense of the word as used in the German animal welfare law.

Recent advances in our knowledge of the Myxozoa.

In the last few years two factors have helped to significantly advance our understanding of the Myxozoa. First, the phenomenal increase in fin fish aquaculture in the 1990s has lead to the increased importance of these parasites; in turn this has lead to intensified research efforts, which have increased knowledge of the development, diagnosis. and pathogenesis of myxozoans. The hallmark discovery in the 1980s that the life cycle of Myxobolus cerebralis requires development of an actinosporean stage in the oligochaete. Tubifex tubifex, led to the elucidation of the life cycles of several other myxozoans. Also, the life cycle and taxonomy of the enigmatic PKX myxozoan has been resolved: it is the alternate stage of the unusual myxozoan, Tetracapsula bryosalmonae, from bryozoans. The 18S rDNA gene of many species has been sequenced, and here we add 22 new sequences to the data set. Phylogenetic analyses using all these sequences indicate that: 1) the Myxozoa are closely related to Cnidaria (also supported by morphological data); 2) marine taxa at the genus level branch separately from genera that usually infect freshwater fishes; 3) taxa cluster more by development and tissue location than by spore morphology; 4) the tetracapsulids branched off early in myxozoan evolution, perhaps reflected by their having bryozoan, rather than annelid hosts; 5) the morphology of actinosporeans offers little information for determining their myxosporean counterparts (assuming that they exist); and 6) the marine actinosporeans from Australia appear to form a clade within the platysporinid myxosporeans. Ribosomal DNA sequences have also enabled development of diagnostic tests for myxozoans. PCR and in situ hybridisation tests based on rDNA sequences have been developed for Myxobolus cerebralis, Ceratomyxa shasta, Kudoa spp., and Tetracapsula bryosalmonae (PKX). Lectin-based and antibody tests have also been developed for certain myxozoans, such as PKX and C. shasta. We also review important diseases caused by myxozoans, which are emerging or re-emerging. Epizootics of whirling disease in wild rainbow trout (Oncorhynchus mykiss) have recently been reported throughout the Rocky Mountain states of the USA. With a dramatic increase in aquaculture of fishes using marine netpens, several marine myxozoans have been recognized or elevated in status as pathological agents. Kudoa thyrsites infections have caused severe post-harvest myoliquefaction in pen-reared Atlantic salmon (Salmo salar), and Ceratomyxa spp., Sphaerospora spp., and Myxidium leei cause disease in pen-reared sea bass (Dicentrarchus labrax) and sea bream species (family Sparidae) in Mediterranean countries.

Amination of grignard reagents with retention of configuration.

[see reaction]. The stereochemistry of electrophilic amination has been probed using the chiral Grignard reagent 5, in which the magnesium-bearing carbon atom is the sole stereogenic center. Amination with azidomethyl phenyl sulfide 1 and with O-sulfonyloxime 2 were found to proceed with full retention of configuration.

Electron microscopic study of a new microsporean Microsporidium epithelialis sp. n. infecting Tubifex sp. (Oligochaeta).

The cytology of a new microsporean parasite Microsporidium epithelialis sp. n. from the intestinal epithelial cells of the freshwater oligochaete Tubifex sp. (Tubificidae) is described. The microsporean occurred together with an actinosporean of the genus Triactinomyxon, which was found between the epithelial cells. The merogonic and sporogonic stages (mature spores included) of the microsporean parasite are monokaryotic. An individual sporophorous vesicle surrounds each spore. The fixed and stained spore has an average dimension of 1.9-2.5 x 0.9-1.2 microm. The spores are oval with a characteristic surface layer, showing ornamentation-like projections, which are in close contact to the exospore. A short polar filament forming three to four coils traverses the polaroplast with two lamellar layers. The ultrastructure and other characteristic features of this microsporean parasite are distinct from those of the microsporean species described so far from oligochaetes.

Whirling disease: host specificity and interaction between the actinosporean stage of Myxobolus cerebralis and rainbow trout Oncorhynchus mykiss.

Scanning electron microscopic studies were conducted on rainbow trout Oncorhynchus mykiss in the first 60 min after their exposure to the triactinomyxon spores of Myxobolus cerebralis. The results demonstrated that as early as 1 min post exposure the whole process, from the attachment of the triactinomyxon spores to the complete penetration of their sporoplasm germs, had occurred. The triactinomyxon spores sought out the secretory openings of mucous cells of the epidermis, the respiratory epithelium and the buccal cavity of trout and used them as portals of entry. Exposure experiments of the triactinomyxon spores of M. cerebralis to non-salmonid fish, such as goldfish Carassius auratus, carp Cyprinus carpio, nose Chondrostoma nasus, medaka Oryzias latipes, guppy Poecilia reticulata and also the amphibian tadpole Rana pipiens as well as to rainbow trout fry indicated a specificity for salmonids. Attempts to activate the triactinomyxon spores by exposure to mucus prepared from cyprinid and salmonid fish showed no significant differences from those conducted in tap water. The results suggest that the simultaneous presence of both mechano- and chemotactic stimuli was required for finding the salmonid fish host.

Rapid and sensitive reverse transcriptase-polymerase chain reaction based detection and differential diagnosis of fish pathogenic rhabdoviruses in organ samples and cultured cells.

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed and applied to the detection and differentiation of viral haemorrhagic septicaemia virus (VHSV) and infectious hematopoietic necrosis virus (IHNV) in organ samples and cultured cells, regardless of the serotype. This method was developed by selecting primer sets corresponding to highly conserved regions of the glycoprotein G-gene sequences of the 2 viruses. The very fast RNA extraction, reverse transcription and PCR permitted us to read the agarose gels within 7 to 9 h after samples, cultured cells and whole fish arrived, which is of great importance when there is reason to believe that VHSV or IHNV may be present. This is also the first report of a large-scale field trial comparing the RT-PCR assay in trout from 30 German fish farms (a total of 330 rainbow trout) with the usual virus isolation and identification method in order to evaluate the efficiency of the RT-PCR assay for general use in fish health management programs. RT-PCR followed by semi-nested PCR using RNA directly extracted from fish tissue turned out to be the most sensitive method. It recognized 9 fish farms as VHS-positive and 7 as IHN-positive. This is 3 VHS- and 4 IHN-farms more than detected by the traditional virus isolation method. By directly examining the tissue by means of a PCR test it was possible to detect viral RNA in acutely and subacutely to chronically diseased fish as well as in asymptomatic VHS/IHN-carrier fish. Therefore, this effective and powerful assay for detecting VHSV and IHNV by means of PCR has great advantages compared with the presently used procedures.

Determination of nuclear DNA concentration in cells of Myxobolus cerebralis and triactinomyxon spores, the causative agent of whirling disease.

Myxobolus cerebralis (Myxozoa: Myxosporea) has a complex two-host life cycle, which begins when waterborne triactinomyxon spores released from the infected oligochaete Tubifex tubifex contact a susceptible trout. Upon contact the triactinomyxon spores attach to the fish and release their sporoplasm cells into the epidermis. At approximately 50 days postinfection, sporogenesis begins, resulting in a large number of M. cerebralis spores in the cartilage of infected fish 6 weeks later. The spores of M. cerebralis can be released from infected fish only after the fish die or are eaten by predators. In both cases, spores released into the aquatic environment can be ingested by oligochaete worms of the species T. tubifex and then develop into the actinosporean triactinomyxon stage in the intestine within about 3 months. The triactinomyxon is the only stage infectious for salmonid fish. We determined the DNA concentration in sporoplasm cells, capsulogenic cells, and valvogenic cells of M. cerebralis spore stages from the trout and of triactinomyxon spore stages from T. tubifex. DNA was visualized using the DNA-specific fluorescent stain DAPI. Our results demonstrate that meiosis occurs only once in the developmental cycle of M. cerebralis in contrast to the previously published hypothesis. This takes place within the pansporocyst found in T. tubifex. Thereafter, the sporoplasm cells of the triactinomyxon spores in T. tubifex and M. cerebralis in trout are diploid.

[Poisonous snakes of Europe]. / Giftschlangen Europas.

Characteristics of poisonous snakes and their toxines are described. The appearance and biology of all European poisonous snakes, eight vipers (family Viperidae) and one opisthoglyph colubride snake (family Colubridae) are given in detail.

Light and electron microscopic studies on the chronological development of Myxobolus cerebralis to the actinosporean stage in Tubifex tubifex.

Whirling disease caused by Myxobolus cerebralis has become the most widely known disease of salmonids in the 1990s. In the last 5 years we have studied many aspects regarding the host-pathogen relationship of this parasite. The parasite's histozoic development causes significant damage to cartilage and induces CNS symptoms by pressure on the brain and spinal cord. Myxobolus cerebralis has a two-host life-cycle involving a salmonid fish and a tubificid oligochaete. Two different stages of sporogony occur, one in each host. Early developmental stages in the fish can be found multiplying in the epidermis and peripheral and central nervous systems. The presporogenic stages then migrate to vertebral and cranial cartilages, where the first sporogonic phase occurs. Mature M. cerebralis spores found in fish cartilage are infectious for T. tubifex when ingested by the oligochaete after destruction of the infected fish. In the gut lumen of the tubificid, the spores extrude their polar capsules and attach to the gut epithelium by polar filaments. The shell valves then open along the suture line and the sporoplasm penetrates between the gut epithelial cells. The binucleate sporoplasm multiplies by schizogony, producing many one-cell stages which begin gamogonic development. As a result of the multiplication process, the intercellular space of the epithelial cells in more than 10 neighbouring worm segments may become infected. At this time (60-90 days p.i.), pansporocysts with eight zygotes start the sporogonic phase. The final stage of this development is a pansporocyst containing eight folded triactinomyxon spores. Shortly afterwards, the spores are liberated into the gut lumen. The spores reach the water either by egestion or following the death of the infected tubificids. Infected tubificids can release triactinomyxons for at least 1 year. The ultrastructure of all four phases, schizogony, gametogony, gametogamy and sporogony, is demonstrated and discussed.

[Clostridium bifermentans infection in grass carp (Ctenopharyngodon idella)]. / Clostridium bifermentans-Infektion bei Grasfischen (Ctenopharyngodon idella).

The outbreak of an infection with Clostridium bifermentans in grass carp (Ctenopharyngodon idella) from a polyculture fish pond is documented.

Occurrence and histological response of Raphidascaris acus (Nematoda: Ascaridoidea) in roach from four lakes differing in water quality.

Seasonality and size-related infection of Raphidascaris acus larvae from the inner organs and intestine of roach (Rutilus rutilus) were studied in 4 lakes of differing water quality and pollution level in Central Finland between August 1985 and November 1986. The influence of R. acus larvae on the liver and pancreatic tissues of roach was examined histologically in additional material from 1989 and 1990. The inner organs of roach were most heavily infected with R. acus in the eutrophic, polluted Lake Vatia (63% of fish infected with 4.0 nematodes/fish) and in the two eutrophic lakes, compared to the oligotrophic Lake Peurunka (23%, 0.8). The prevalence of free R. acus larvae in the intestine of roach was almost as high but the intensity only about half of that found in the inner organs. The prevalence of infection had significantly higher values in autumn in most cases, and larvae accumulated in the inner organs and intestine of older roach. In histological studies it was found that larvae occurred more often in the pancreatic tissue than in the liver, but in both organs the majority of the larvae were dead and partly destroyed. The most typical host response against R. acus was a chronic granulomatous inflammatory reaction. Granulomas and developing granulomas containing worms at different stages of degeneration are described; they were found in all of the lakes studied throughout the year and also in one and the same fish. On average only 37 and 21% of the worms in the liver and pancreas, respectively, were alive. No obvious difference in the histological response against R. acus was noted between the lakes.

Light- and electron microscopical studies on the prolonged toxicity of trichloroethylene on rainbow trout (Oncorhynchus mykiss).

Trichloroethylene, an organochlorine compound used as solvent in numerous industrial processes, was studied with regard to its effects on rainbow trout Oncorhynchus mykiss. Fish were exposed to trichloroethylene via the surrounding water in sublethal concentrations (0.5; 2.5 mg/l) for a period of 21 or 28 days. Three different commercial products of trichloroethylene, all highly purified but varying in quality and amount of stabilizing agents were used. Subchronic exposure resulted in forced apoptosis as well as adaptive and degenerative changes at the subcellular and cellular level in gills, liver, spleen, head- and trunk kidney at the lower concentration. At the higher concentration, necrotic lesions mainly in liver, spleen and head-kidney were found. Trichloroethylene showed particular affinity to the haematopoietic tissue with proliferation and elevated phagocytic activity of reticulo-endothelial cells. Moreover, an increase in phagocytosis of red blood cells which showed abnormalities in ultrastructure was striking. The histopathologic changes after exposure to three different commercial products of trichloroethylene varying in content of stabilizing agents did not show distinct variations.

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.