Search results for "INFECTIONS"
showing 10 items of 2671 documents
Diagnostic accuracy of the light microscope method to detect the eggs of Cardicola spp. in the gill filaments of the bluefin tuna.
2017
Trematode blood flukes of the genus Cardicola are potentially lethal in bluefin tuna cultures. The present study proposed a new method to detect aporocotylid eggs in tuna gills. Aporocotylid eggs were detected by analysing a pair of gill filaments of five transversal areas of the eight holobranches of one hundred Atlantic bluefin tuna and observed with glycerol and a stereomicroscope with an oblique brightfield. Data were gathered according to holobranches, transversal areas and their combination. Eggs were uniformly distributed among the holobranches, but they had the highest prevalence in the second and fifth transversal areas, which is controversial with respect to previous studies of eg…
Dactylogyrids on the gills of roach in central Finland: Features of infection and species composition
1991
Monogenean parasites were examined from the gills of 660 roach (Rutilus rutilus) in four interconnected lakes in Central Finland between February and November 1986 and in three of the same lakes between February and December 1988. One of the lakes is eutrophic and polluted due to a paper and pulp mill, one is oligotrophic and in a natural state, and the other two lakes are eutrophic. The prevalence of Dactylogyrus infection was always high. Differences between the lakes and the years were observed in the intensity of infection, which was significantly higher in the polluted lake. The intensity was also higher in older fish. Nine Dactylogyrus species were found, and of these D. crucifer and …
Effect of Pseudomonas sp. MT5 baths on Flavobacterium columnare infection of rainbow trout and on microbial diversity on fish skin and gills
2005
Use of Pseudomonas sp. strain MT5 to prevent and treat Flavobacterium columnare infection was studied in 2 experiments with fingerling rainbow trout Oncorhynchus mykiss. In the first experiment, length heterogeneity analysis of PCR-amplified DNA fragments (LH-PCR) was used to assess the effect of antagonistic baths on the microbial diversity of healthy and experimentally infected fish. In the 148 samples studied, no difference was found between bathed and unbathed fish, and 3 fragment lengths were detected most frequently: 500 (in 75.7% of the samples), 523 (62.2%) and 517 bp (40.5%). The species contributing to these fragment sizes were Pseudomonas sp., Rhodococcus sp. and F. columnare, re…
A New Species of Ligophorus (Monogenea: Dactylogyridae) from the gills of the Flathead Mullet Mugil cephalus (Teleostei: Mugilidae) from Mexico
2015
AbstractA new monogenean species, Ligophorus yucatanensis n. sp. from the gills of the flathead mullet Mugil cephalus from the Yucatan Peninsula, Mexico, is described. The new species can be differentiated from all other species of Ligophorus by the morphology of the accessory piece of the copulatory organ. Its main lobe is cylindrical, tunnelled expanded distally, slightly bowed with a characteristic membranous opening at level of medial bifurcation of the accessory piece, forming a thick-walled bulbshaped expansion that ends in a round labium. The secondary lobe is spatulate, straight, and shorter than the main lobe. In addition, the new species can be distinguished from other species by …
Early steps in the European eel (Anguilla anguilla)–Vibrio vulnificus interaction in the gills: Role of the RtxA13 toxin
2015
Vibrio vulnificus is an aquatic gram-negative bacterium that causes a systemic disease in eels called warm-water vibriosis. Natural disease occurs via water born infection; bacteria attach to the gills (the main portal of entry) and spread to the internal organs through the bloodstream, provoking host death by haemorrhagic septicaemia. V.vulnificus produces a toxin called RtxA13 that hypothetically interferes with the eel immune system facilitating bacterial invasion and subsequent death by septic shock. The aim of this work was to study the early steps of warm-water vibriosis by analysing the expression of three marker mRNA transcripts related to pathogen recognition (tlr2 and tlr5) and in…
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.)
2010
Abstract Background For more than three decades, diseases caused by salmonid alphaviruses (SAV) have become a major problem of increasing economic importance in the European fish-farming industry. However, experimental infection trials with SAV result in low or no mortality i.e very different from most field outbreaks of pancreas disease (PD). This probably reflects the difficulties in reproducing complex biotic and abiotic field conditions in the laboratory. In this study we looked at the relationship between SAV-infection in salmon and sub-lethal environmental hypoxia as a result of reduced flow-through in tank systems. Results The experiment demonstrated that constant reduced oxygen leve…
REDESCRIPTION OF ALLENCOTYLA MCINTOSHI PRICE, 1962 (MONOGENEA), WITH AN EMENDED DIAGNOSIS OF ALLENCOTYLA PRICE, 1962
2003
The original description of the type species of Allencotyla, A. mcintoshi Price, 1962, was based on 5 specimens collected from 1 amberjack Seriola lalandi in Florida. In this study, A. mcintoshi is redescribed based on new specimens collected from juvenile greater amberjacks S. dumerili captured off the Spanish Mediterranean coast and maintained in experimental culture tanks. Except for a slightly smaller size, individuals of S. dumerili were morphologically similar to the type specimens. However, reexamination of the type material and examination of the new specimens revealed the following discrepancies with respect to the original description: (1) the vaginal pore is unarmed and covered w…
Transmission to Eels, Portals of Entry, and Putative Reservoirs of Vibrio vulnificus Serovar E (Biotype 2)
2001
ABSTRACT Vibrio vulnificus serovar E (formerly biotype 2) is the etiologic agent that is responsible for the main infectious disease affecting farmed eels. Although the pathogen can theoretically use water as a vehicle for disease transmission, it has not been isolated from tank water during epizootics to date. In this work, the mode of transmission of the disease to healthy eels, the portals of entry of the pathogen into fish, and their putative reservoirs have been investigated by means of laboratory and field experiments. Results of the experiments of direct and indirect host-to-host transmission, patch contact challenges, and oral-anal intubations suggest that water is the prime vehicle…
Flavobacterium columnare colony types: connection to adhesion and virulence?
2008
Four different colony morphologies were produced by Flavobacterium columnare strains on Shieh agar plate cultures: rhizoid and flat (type 1), non-rhizoid and hard (type 2), round and soft (type 3), and irregularly shaped and soft (type 4). Colonies produced on AO agar differed from these to some extent. The colony types formed on Shieh agar were studied according to molecular characteristics [Amplified Fragment Length Polymorphism (AFLP), Automated Ribosomal Intergenic Spacer Analysis (ARISA), and whole cell protein SDS-PAGE profiles], virulence on rainbow trout fingerlings, and adhesion on polystyrene and fish gills. There were no molecular differences between colony types within one strai…
Phage-driven loss of virulence in a fish pathogenic bacterium
2012
Parasites provide a selective pressure during the evolution of their hosts, and mediate a range of effects on ecological communities. Due to their short generation time, host-parasite interactions may also drive the virulence of opportunistic bacteria. This is especially relevant in systems where high densities of hosts and parasites on different trophic levels (e.g. vertebrate hosts, their bacterial pathogens, and virus parasitizing bacteria) co-exist. In farmed salmonid fingerlings, Flavobacterium columnare is an emerging pathogen, and phage that infect F. columnare have been isolated. However, the impact of these phage on their host bacterium is not well understood. To study this, four s…