Search results for "Virulence"

Data from: Minor environmental concentrations of antibiotics can modify bacterial virulence in co-infection with a non-targeted parasite

2018

Leakage of medical residues into the environment can significantly impact natural communities. For example, antibiotic contamination from agriculture and aquaculture can directly influence targeted pathogens, but also other non-targeted taxa of commensals and parasites that regularly co-occur and co-infect the same host. Consequently, antibiotics could significantly alter interspecific interactions and epidemiology of the co-infecting parasite community. We studied how minor environmental concentration of antibiotic affects the coinfection of two parasites, the bacterium Flavobacterium columnare and the fluke Diplostomum pseudospathaceum, in their fish host. We found that antibiotic in feed…

Data from: Coinfection outcome in an opportunistic pathogen depends on the inter-strain interactions

2017

Background In nature, organisms are commonly coinfected by two or more parasite strains, which has been shown to influence disease virulence. Yet, the effects of coinfections of environmental opportunistic pathogens on disease outcome are still poorly known, although as host-generalists they are highly likely to participate in coinfections. We asked whether coinfection with conspecific opportunistic strains leads to changes in virulence, and if these changes are associated with bacterial growth or interference competition. We infected zebra fish (Danio rerio) with three geographically and/or temporally distant environmental opportunist Flavobacterium columnare strains in single and in coinf…

Data from: Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen

2018

Predicting the effects of global increase in temperatures on disease virulence is challenging, especially for environmental opportunistic bacteria, because pathogen fitness may be differentially affected by temperature within and outside host environment. So far, there is very little empirical evidence on the connections between optimal temperature range and virulence in environmentally growing pathogens. Here we explored if the virulence of an environmentally growing opportunistic fish pathogen, Flavobacterium columnare, is malleable to evolutionary changes via correlated selection on thermal tolerance. To this end, we experimentally quantified the thermal performance curves (TPCs) for max…

Data from: Enriched rearing environment and wild genetic background can enhance survival and disease resistance of salmonid fishes during parasite ep…

2016

The importance and volume of aquaculture is increasing world-wide. Rearing practices play a key role in determining growth rate, survival and disease resistance in aquaculture fishes. Recent evidence suggests that in comparison with a standard stimulus-poor rearing environment, an enriched or variable rearing environment has significant positive effects on several traits underlying growth and well-being of fish. However, the effect of enriched rearing on one of the most important threats for aquaculture development, occurrence of parasitic infections, remains unknown. We used surveillance data of experimental salmonid populations of wild and hatchery origin under semi-natural parasite expos…

Viruses of Cetaceans

2011

Neurotropism in newborn hamsters of plaque purified measles virus clones

1976

Three plaque purified measles virus clones displayed a different neurotropism in newborn hamsters.

Seroepidemiology of pertussis infection in an urban childhood population in Cameroon.

1991

In 1989, the prevalence of IgG antibodies to pertussis toxin (PT) in a sample of 367 unvaccinated apparently healthy children 5-14 years old was estimated by ELISA in Kumba City (Cameroon). Children were recruited using a systematic random sampling from six primary schools located in different districts of the city. The sample was representative of the various socioeconomic classes. The overall prevalence was 75%; it increased from 62% in 5 year old children to 81% in children 12-14 years old (P less than 0.01). IgG antibody prevalence was positively related to the family size. Children belonging to households of nine or more members had a 2.2-fold risk (C.I. 95 per cent = 1.1-4.6) of previ…

Plasmid diversity in Vibrio vulnificus biotypes.

2009

Vibrio vulnificus is a heterogeneous bacterial species that can be virulent for humans and fish. Virulence in fish seems to rely on a recently described plasmid that can be transmitted between strains, aided by a conjugative plasmid. The main objective of this work was to analyse the plasmid content of a wide collection of strains from the three biotypes of the species, as well as to identify putative conjugative and virulence plasmids by means of Southern hybridization with specific probes and sequence analysis of selected gene markers. We found 28 different plasmid profiles in a total of 112 strains, which were relatively biotype- or serovar-specific. Biotype 1 lacked high-molecular-mass…

Bacteriophage Adherence to Mucus Mediates Preventive Protection against Pathogenic Bacteria

2019

The mucosal surfaces of animals are habitat for microbes, including viruses. Bacteriophages—viruses that infect bacteria—were shown to be able to bind to mucus. This may result in a symbiotic relationship in which phages find bacterial hosts to infect, protecting the mucus-producing animal from bacterial infections in the process. Here, we studied phage binding on mucus and the effect of mucin on phage-bacterium interactions. The significance of our research is in showing that phage adhesion to mucus results in preventive protection against bacterial infections, which will serve as basis for the development of prophylactic phage therapy approaches. Besides, we also reveal that exposure to m…

Staphylococcus epidermidis virulences faktori un epidemioloģiskā nozīme

2016

Staphylococcus epidermidis svarīgākais virule nces faktors ir biofilmas veidošana. Lai diferencētu komensālos celmus no kolonizējošiem un invazīviem celmiem, pētījumā tika izmantotas fenotipiskās metodes, nosakot biofilmas veidošanu, antibiogrammu, un molekulārās bioloģijas metodes, nosakot virulences gēnus aap / ica A un mec A. Rezultāti liecina, ka biofilmu veidošana raksturīga klīniskajiem celmiem, statistiski ticami biežāk gēni aap/ica A bija noteikti klīniskajos S.epidermidis celmos, tie vis biežāk bija rezistenti pret meticilīnu (97,8%). S.epidermidis tipēšanai pirmo reizi tika pielietota MLST (multilokusu sekvenču tipēšana) metode. Pētījuma rezultāti ļauj secināt par S.epidermidis ge…