Search results for "Fish diseases"
showing 10 items of 232 documents
Speciation of the Paradeontacylix spp. (Sanguinicolidae) of Seriola dumerili. Two new species of the genus Paradeontacylix from the Mediterranean.
2008
Abstract Two new species of teleost blood fluke belonging to the sanguinicolid genus Paradeontacylix are described from the greater amberjack, Seriola dumerili , i.e. Paradeontacylix ibericus n. sp. from the Iberian Peninsula and Paradeontacylix balearicus n. sp. from the Balearic Islands. P. ibericus n. sp. and P. balearicus n. sp. show morphological similarities with Paradeontacylix kampachi and Paradeontacylix grandispinus respectively, which occur in mixed infection in S. dumerili from Japan. Multivariate analysis of morphometrical data provided statistical evidence for the separation of four species. However, component by component analysis did not show statistically significant differ…
A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates
2015
Background Columnaris disease caused by Flavobacterium columnare is a serious problem in aquaculture, annually causing large economic losses around the world. Despite considerable research, the molecular epidemiology of F. columnare remains poorly understood. Methods We investigated the population structure and spatiotemporal changes in the genetic diversity of F. columnare population in Finland by using a multilocus sequence typing (MLST) and analysis (MLSA) based on DNA sequence variation within six housekeeping genes. A total of 83 strains of F. columnare were collected from eight different areas located across the country between 2003 and 2012. Results Partial sequencing of six housekee…
The Fish Pathogen Vibrio vulnificus Biotype 2: Epidemiology, Phylogeny, and Virulence Factors Involved in Warm-Water Vibriosis
2015
ABSTRACT Vibrio vulnificus biotype 2 is the etiological agent of warm-water vibriosis, a disease that affects eels and other teleosts, especially in fish farms. Biotype 2 is polyphyletic and probably emerged from aquatic bacteria by acquisition of a transferable virulence plasmid that encodes resistance to innate immunity of eels and other teleosts. Interestingly, biotype 2 comprises a zoonotic clonal complex designated as serovar E that has extended worldwide. One of the most interesting virulence factors produced by serovar E is RtxA1 3 , a multifunctional protein that acts as a lethal factor for fish, an invasion factor for mice, and a survival factor outside the host. Two practically id…
Method for Specific Identification of the Emerging Zoonotic Pathogen Vibrio vulnificus Lineage 3 (Formerly Biotype 3).
2020
ABSTRACT Vibrio vulnificus is a zoonotic pathogen that is spreading worldwide due to global warming. Lineage 3 (L3; formerly biotype 3) includes the strains of the species with the unique ability to cause fish farm-linked outbreaks of septicemia. The L3 strains emerged recently and are particularly virulent and difficult to identify. Here, we describe a newly developed PCR method based on a comparative genomic study useful for both rapid identification and epidemiological studies of this interesting emerging group. The comparative genomic analysis also revealed the presence of a genetic duplication in the L3 strains that could be related to the unique ability of this lineage to produce sept…
Starvation can diversify the population structure and virulence strategies of an environmentally transmitting fish pathogen.
2013
Background Generalist bacterial pathogens, with the ability for environmental survival and growth, often face variable conditions during their outside-host period. Abiotic factors (such as nutrient deprivation) act as selection pressures for bacterial characteristics, but their effect on virulence is not entirely understood. “Sit and wait” hypothesis expects that long outside-host survival selects for increased virulence, but maintaining virulence in the absence of hosts is generally expected to be costly if active investments are needed. We analysed how long term starvation influences bacterial population structure and virulence of an environmentally transmitting fish pathogen Flavobacteri…
Comparing the different morphotypes of a fish pathogen - implications for key virulence factors in Flavobacterium columnare
2014
Background: Flavobacterium columnare (Bacteroidetes) is the causative agent of columnaris disease in farmed freshwater fish around the world. The bacterium forms three colony morphotypes (Rhizoid, Rough and Soft), but the differences of the morphotypes are poorly known. We studied the virulence of the morphotypes produced by F. columnare strain B067 in rainbow trout ( Onconrhynchus mykiss ) and used high-resolution scanning electron microscopy to identify the fine structures of the cells grown in liquid and on agar. We also analysed the proteins secreted extracellularly and in membrane vesicles to identify possible virulence factors. Results: Only the Rhizoid morphotype was virulent in rain…
Post-larval development of the microcotylid monogenean Sparicotyle chrysophrii (Van Beneden and Hesse, 1863): comparison with species of Microcotylid…
2011
Abstract The chronology of post-larval development in S. chrysophrii, a polyopisthocotylean monogenean parasite of the gilthead seabream (Sparus aurata L.), was experimentally studied. It is compared with other species within the Microcotylidae and the Heteraxinidae, including an analysis of the changes in attachment and the growth rate. Gilthead seabreams infected by larvae of S. chrysophrii were killed periodically in order to collect the different developmental stages. Parasite total body length, haptor length, largest clamp width, and total number of clamps were recorded. Specimens of S. chrysophrii in culture conditions at 20 °C became gravid after 26–30 days, with 37 pairs of clamps. …
Vibrio sinaloensis sp. nov., isolated from the spotted rose snapper, Lutjanus guttatus Steindachner, 1869.
2008
Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA hybridization and physiological characterization. Typing analysis by means of rep-PCR showed that all nine strains were highly homogeneous, with similarities above 94 %. The strains were isolated from the same geographical area (Mazatlan, Sinaloa state, Mexico) and the same type of host (cultured rose snapper, Lutjanus guttatus), although from different individuals and organs. Comparison of the almost-complete 16S rRNA gene sequences of five strains showed that they belonged to the genus Vibrio and are closely related to the type strains of Vibrio brasiliensis and Vibrio hepatarius, with simila…
Molecular diversity and growth features of Flavobacterium columnare strains isolated in Finland
2006
ABSTRACT: Columnaris disease caused by Flavobacterium columnare is a problem in fish farmingworldwide. During the last 15 yr, outbreaks have started to emerge in Finland. Flavobacteriumcolumnare Type Strain NCIMB 2248 T and 30 Finnish F. columnare isolates were studied usinganalysis of 16S rDNA by restriction-fragment length polymorphism (16S RFLP), length heterogeneityanalysis of polymerase chain reaction (LH-PCR) products, automated ribosomal intergenic spaceranalysis (ARISA), and 16S rDNA sequence analysis. All isolates fell into RFLP Genomovar I and hadthe same length in the LH-PCR analysis. Based on ARISA, 8 genetically different strains wereselected for further analyses. The growth of…
Identification of DNA sequences specific for Vibrio vulnificus biotype 2 strains by suppression subtractive hybridization.
2005
ABSTRACT Vibrio vulnificus can be divided into three biotypes, and only biotype 2, which is further divided into serovars, contains eel-virulent strains. We compared the genomic DNA of a biotype 2 serovar E isolate (tester) with the genomic DNAs of three biotype 1 strains by suppression subtractive hybridization and then tested the distribution of the tester-specific DNA sequences in a wide collection of bacterial strains. In this way we identified three plasmid-borne DNA sequences that were specific for biotype 2 strains irrespective of the serovar and three chromosomal DNA sequences that were specific for serovar E biotype 2 strains. These sequences have potential for use in the diagnosis…