Search results for "taudinaiheuttajat"

Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen

2020

Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemic…

Glochidial infection by the endangered Margaritifera margaritifera (Mollusca) increased survival of salmonid host (Pisces) during experimental Flavob…

2021

AbstractCo-infections are common in host-parasite interactions, but studies about their impact on the virulence of parasites/diseases are still scarce. The present study compared mortality induced by a fatal bacterial pathogen, Flavobacterium columnare between brown trout infected with glochidia from the endangered freshwater pearl mussel, Margaritifera margaritifera, and uninfected control fish during the parasitic period and after the parasitic period (i.e. glochidia detached) in a laboratory experiment. We hypothesised that glochidial infection would increase host susceptibility to and/or pathogenicity of the bacterial infection. We found that the highly virulent strain of F. columnare c…

The effects of Borrelia infection on its wintering rodent host

2022

AbstractIn seasonal environments, appropriate adaptations are crucial for organisms to maximize their fitness. For instance, in many species, the immune function has been noticed to decrease during winter, which is assumed to be an adaptation to the season’s limited food availability. Consequences of an infection on the health and survival of the host organism could thus be more severe in winter than in summer. Here, we experimentally investigated the effect of a zoonotic, endemic pathogen, Borrelia afzelii infection on the survival and body condition in its host, the bank vole (Myodes glareolus), during late autumn–early winter under semi-natural field conditions in 11 large outdoor enclos…

Does the freshwater mussel Anodonta anatina remove the fish pathogen Flavobacterium columnare from water?

2021

AbstractGlobal decline of freshwater mussels (Unionoida) is threatening biodiversity and the essential ecosystem services that mussels provide. As filter-feeding organisms, freshwater mussels remove phytoplankton and suspended particles from the water. By filtering bacteria, freshwater mussels also decrease pathogen loads in the water. The objective of this study was to evaluate whether the common freshwater bivalve Anodonta anatina (duck mussel) could remove the bacterial fish pathogen Flavobacterium columnare from the water. Mussels reduced bacteria in both of the two experiments performed, so that the bacterial concentration at the end of the 96-h monitoring in mussel treatments was only…

The influence of infective dose, nutrient availability and coinfection on virulence of Flavobacterium columnare : implications of intensive aquacultu…

2016

Ecological factors are known to affect disease dynamics and even lead to disease emergence. Especially in opportunistic, environmentally transmitted pathogens, the environment may significantly contribute to pathogen virulence. Intensive farming, including aquaculture, has been suggested to create conditions favouring development of highly virulent pathogens. At Finnish fish farms, epidemics caused by opportunistic Flavobacterium columnare have been constantly increasing in their prevalence and severity since the 1980’s. Yet, factors behind the increased virulence of the pathogen and their mechanisms of action have largely remained unsolved. In this thesis, I explore the effects of infectio…

Exploring evolutionary responses to increasing temperature in an environmental opportunistic pathogen

2017

Genetic and environmental factors associated with the virulence of fish pathogen Flavobacterium columnare

2016

Impact of biotic and abiotic factors on bacterial virulence

2013

Toward Comprehensive Plant Microbiome Research

2020

Microbes have driven eco-evolutionary adaptations organizing biodiversity from the origin of life. They are ubiquitous and abundant, facilitating the biochemical processes that make Earth habitable and shape ecosystem structures, functions, and services. Recent studies reveal that commensalistic and beneficial microbes associated with wild and domesticated plants may aid in establishing sustainable agriculture for a changing climate. However, developing microbe-based biotechnologies and ecosystem services requires a thorough understanding of the diversity and complexity of microbial interactions with each other and with higher organisms. We discuss the hot and blind spots in contemporary re…

Experimental ecology on the interaction between the Puumala hantavirus and its host, the bank vole

2006

Eva Kallio tutki väitöskirjatyössään ihmisissä myyräkuumetta aiheuttavan, Hantaviruksiin kuuluvan Puumala-viruksen ja sen isäntälajin metsämyyrän välistä vuorovaikutussuhdetta. Tutkimuksessa selvisi viruksen säilyvän infektiokykyisenä pitkään isännän ulkopuolellakin ja voivan tarttua myyrästä toiseen tai myyrästä ihmiseen ilman suoraa kontaktia. Kallio osoitti myös ensimmäisen kerran hantaviruksen olevan haitallinen isäntälajilleen.Kallion osoittaman Puumala-viruksen ja metsämyyrän välisen vuorovaikutussuhteen piirteet voivat osaltaan vaikuttaa ihmisten myyräkuume-epidemioiden ilmentymiseen. Uuden tiedon avulla pystytään myös yhä luotettavammin mallintamaan ja ennustamaan epidemioiden esiin…