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Fish Diseases (fish + disease)
Selected AbstractsAn isolate and sequence database of infectious haematopoietic necrosis virus (IHNV)JOURNAL OF FISH DISEASES, Issue 6 2010S P Jonstrup Abstract In the field of fish diseases, the amount of relevant information available is enormous. Internet-based databases are an excellent tool for keeping track of the available knowledge in the field. Fishpathogens.eu was launched in June 2009 with the aim of collecting, storing and sorting data on fish pathogens. The first pathogen to be included was the rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Here, we present an extension of the database to also include infectious haematopoietic necrosis virus (IHNV). The database is developed, maintained and managed by the European Community Reference Laboratory for Fish Diseases and collaborators. It is available at http://www.fishpathogens.eu/ihnv. [source] Molecular characterization of the fish-pathogenic fungus Aphanomyces invadansJOURNAL OF FISH DISEASES, Issue 5 2003J H Lilley Abstract Aphanomyces invadans (Saprolegniaceae) is a peronosporomycete fungus associated with the serious fish disease, epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis. In this study, interspecific relationships were examined between A. invadans isolates and other aquatic animal pathogenic Saprolegniaceae, and saprophytic Saprolegniaceae from EUS-affected areas. Restriction fragment length polymorphisms and sequences of ribosomal DNA confirmed that A. invadans is distinct from all other species studied. A sequence from the internal transcribed spacer region ITS1, unique to A. invadans, was used to design primers for a PCR-based diagnostic test. Intraspecific relationships were also examined by random amplification of polymorphic DNA using 20 isolates of A. invadans from six countries. The isolates showed a high degree of genetic homogeneity using 14 random ten-mer primers. This provides evidence that the fungus has spread across Asia in one relatively rapid episode, which is consistent with reports of outbreaks of EUS. Physiological distinctions between A. invadans and other Aphanomyces species based on a data set of 16 growth parameters showed remarkable taxonomic congruence with the molecular phylogeny. [source] Identification and pathogenicity of Vibrio ponticus affecting cultured Japanese sea bass, Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes)LETTERS IN APPLIED MICROBIOLOGY, Issue 1 2007Z.Y. Xie Abstract Aims:, To rapidly determine the causative agent of mass death in Lateolabrax japonicus in Zhelin Bay of Guangdong Province in China in April 2004. Methods and Results:, Thirty-six strains, numbered sequentially from RP01 to RP36, were isolated from six diseased fish. All of the strains were identified as being of the same vibrio species according to the results of universal primer PCR combined with DGGE (UPPCR-DGGE). RP30 was one of these strains that was randomly selected and analysed by using a morphological, physiological and biochemical plate, Biolog GN2 Microplate System and API 20E system. Furthermore, RP30, 16S rDNA was sequenced and aligned in Genbank. Its virulence to Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was also tested. RP30 is most closely related to four Vibrio ponticus strains (99·3% similarity). LD50s were 2·5 (×103 CFU per fish for intraperitoneal inoculation (IP) and 3·2 (×103 CFU per fish for intramuscular inoculation (IM), respectively. Conclusions:, The investigated pathogenic agent of Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was V. ponticus. Significance and Impact of the Study:, UPPCR-DGGE is very helpful in epidemiologic investigation. Interestingly, this is the first report that V. ponticus infects cultured marine fish. DGGE was likewise first introduced to epidemiologic investigation of fish disease. [source] Live Spirulina (Arthrospira platensis) as a growth and immunity promoter for Nile tilapia, Oreochromis niloticus (L.), challenged with pathogenic Aeromonas hydrophilaAQUACULTURE RESEARCH, Issue 9 2009Mohsen Abdel-Tawwab Abstract The use of antibiotics to control fish disease is one of the constraints in tilapia farming. Hence, the use of probiotic and live organisms as alternative strategies has received much more attention. This study was undertaken to evaluate the use of Spirulina (Arthrospir platensis) as a growth and immunity promoter for Nile tilapia, Oreochromis niloticus (L.). Fish (1.88 g) were randomly distributed at 20 fish per 100 L aquarium and fed a diet containing either 0.0, 1.25, 2.5, 5.0, 7.5 or 10.0 g Spirulina kg,1 diet for 12 weeks. After the feeding trial, fish of each treatment were challenged by pathogenic Aeromonas hydrophila, which was given by an interperitoneal injection, and they were kept under observation for 10 days to record any abnormal clinical signs and the daily mortality rate. The growth-promoting influence of Spirulina was observed with fish, and the optimum growth and feed utilization were obtained at 5.0 g Spirulina kg,1 diet. No significant changes were observed in fish survival among the different treatments. Spirulina supplementation improved the protein and lipid contents in fish bodies without significant differences among them, especially when fed 2.5,10.0 g kg,1 diet, but no significant differences in the moisture and ash contents were observed among different treatments. The physiological parameters were improved when fish were fed a Spirulina-enriched diet. However, the highest red blood cells, white blood cells and nitro blue tetrazolium values were obtained at 5.0,10.0 g Spirulina kg,1 diet; meanwhile, the lowest value was obtained in the control. Total fish mortality due to A. hydrophila infection decreased with an increase in the Spirulina level in fish diets. These results indicate that Spirulina supplement is promising as an alternative method to antibiotics for disease prevention in tilapia aquaculture, and the optimum level of Spirulina in the fish diet should be 5.0,10.0 g kg,1 diet. [source] When fathers make the difference: efficacy of male sexually selected antimicrobial glands in enhancing fish hatching successFUNCTIONAL ECOLOGY, Issue 1 2010Matteo Pizzolon Summary 1.,Egg and offspring resistance to pathogens is a major determinant of survival and has been mainly ascribed to maternal factors. However, paternal production of antimicrobials was recently suggested to increase offspring survival in species where males perform egg care. 2.,In the peacock blenny, Salaria pavo, a demersal spawning species where males exhibit a pair of anal glands producing lysozyme-like compounds, we tested the antimicrobial activity and the egg protection efficacy of these glands. The anal gland secretion (AGS) has an inhibitory effect on the growth of both Gram-negative and Gram-positive bacteria, including those causing the most severe fish diseases in marine culture. The egg clutches cared for by males deprived of anal glands have a significantly lower survival rate than those cared for by sham-operated males and non-viable eggs showed clear signs of bacterial infection. 3.,Anal gland secretion production and its protein content are proportional to gland size. In species where male parental care plays a crucial role in offspring survival, females are expected to assess mates selecting those traits that are reliably associated with parental ability. Hence, we experimentally challenged females with dummy males differing in anal gland size. Females definitely preferred dummy males with larger anal glands, suggesting that their choice is driven by the pursuit of direct fecundity benefits. 4.,These findings indicate that antimicrobial production is a crucial component of male parental care. The contribution of antimicrobials to male performance as fathers suggests that the development of traits devoted to this function may influence male attractiveness and be sexually selected. [source] An isolate and sequence database of infectious haematopoietic necrosis virus (IHNV)JOURNAL OF FISH DISEASES, Issue 6 2010S P Jonstrup Abstract In the field of fish diseases, the amount of relevant information available is enormous. Internet-based databases are an excellent tool for keeping track of the available knowledge in the field. Fishpathogens.eu was launched in June 2009 with the aim of collecting, storing and sorting data on fish pathogens. The first pathogen to be included was the rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Here, we present an extension of the database to also include infectious haematopoietic necrosis virus (IHNV). The database is developed, maintained and managed by the European Community Reference Laboratory for Fish Diseases and collaborators. It is available at http://www.fishpathogens.eu/ihnv. [source] Effects of temperature on disease progression and swimming stamina in Ichthyophonus -infected rainbow trout, Oncorhynchus mykiss (Walbaum)JOURNAL OF FISH DISEASES, Issue 10 2009R Kocan Abstract Rainbow trout, Oncorhynchus mykiss, were infected with Ichthyophonus sp. and held at 10 °C, 15 °C and 20 °C for 28 days to monitor mortality and disease progression. Infected fish demonstrated more rapid onset of disease, higher parasite load, more severe host tissue reaction and reduced mean-day-to-death at higher temperature. In a second experiment, Ichthyophonus -infected fish were reared at 15 °C for 16 weeks then subjected to forced swimming at 10 °C, 15 °C and 20 °C. Stamina improved significantly with increased temperature in uninfected fish; however, this was not observed for infected fish. The difference in performance between infected and uninfected fish became significant at 15 °C (P = 0.02) and highly significant at 20 °C (P = 0.005). These results have implications for changes in the ecology of fish diseases in the face of global warming and demonstrate the effects of higher temperature on the progression and severity of ichthyophoniasis as well as on swimming stamina, a critical fitness trait of salmonids. This study helps explain field observations showing the recent emergence of clinical ichthyophoniasis in Yukon River Chinook salmon later in their spawning migration when water temperatures were high, as well as the apparent failure of a substantial percentage of infected fish to successfully reach their natal spawning areas. [source] Bacterial diversity in various coastal mariculture ponds in Southeast China and in diseased eels as revealed by culture and culture-independent molecular techniquesAQUACULTURE RESEARCH, Issue 9 2010Yonghui Zeng Abstract Mariculture ponds are widely distributed in Chinese coasts and have become a threat to the health of coastal ecosystems. In order to improve our understanding on the microbial composition in mariculture environments, we sampled a variety of ponds farming different animals or plants around the Dongshan Island and Xiamen Island in Southeast China and isolated cultures from the tissues of diseased eels. Analysis by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE), clone library and direct culturing methods revealed highly diverse bacterial communities in these samples. Bacterial communities in the Dongshan samples were dominated by Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes. The Gracilaria verrucosa pond harbours the most abundant species (20 DGGE bands), followed by Epinephelus diacanthus pond (18 bands), Haliotis diversicolor supertexta pond I (18 bands) and Penaeus vannamei pond (11 bands). In comparison with surface waters, Penacus orientalis pond sediment showed a much more complex bacterial community, from which only sequences affiliated with Deltaproteobacteria, Firmicutes, Acidobacteria and candidate phylum TM6 were found. Bacterial cultures in diseased eels were closely related to two pathogenic genera, Aeromonas in Gammaproteobacteria and Bacillus, in Firmicutes. Clones affiliated with another two genera, Escherichia and Vibrio, that have pathogenic potentials were also identified. Phylogenetic analysis of a total of 131 sequences showed that 48.9% of the sequences were clustered into Gammaproteobacteria and formed the most abundant group, followed by Alphaproteobacteria (19.1%), Firmicutes (7.6%), Bacteroidetes (5.3%), Deltaproteobacteria (5.3%), Actinobacteria (4.6%), Chloroplast (3.8%), Acidobacteria (2.3%), Cyanobacteria (1.5%), Betaproteobacteria (0.7%) and TM6 (0.7%). 43.7% (28/64) of the phylogenetic clusters cannot be classified into any known genus and 44.3% (58/131) of the sequences show <95% similarity to public database records, suggesting that abundant novel species exist in mariculture ponds. Gathering bacterial diversity data in mariculture ponds and diseased fish is meaningful for the prevention and control of fish diseases and for the improvement of our understanding of microbial ecology in a pond environment. 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