Search results for "parasitismi"
showing 10 items of 36 documents
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…
Coinfection patterns of two marine apicomplexans are not associated with genetic diversity of their polychaete host.
2022
Coinfections of two or more parasites within one host are more of a rule than an exception in nature. Interactions between coinfecting parasites can greatly affect their abundance and prevalence. Characteristics of the host, such as genetic diversity, can also affect the infection dynamics of coinfecting parasites. Here we investigate for the first time the association of coinfection patterns of two marine apicomplexans, Rhytidocystis sp. and Selenidium pygospionis, with the genetic diversity of their host, the polychaete Pygospio elegans, from natural populations. Host genetic diversity was determined with seven microsatellite loci and summarized as allelic richness, inbreeding coefficient…
The roles of foraging environment, host species, and host diet for a generalist pupal parasitoid
2018
Even for parasitoids with a wide host range, not all host species are equally suitable, and host qualityoften depends on the plant the host feeds on. We compared oviposition choice and offspring perfor-mance of a generalist pupal parasitoid,Pteromalus apum(Retzius) (Hymenoptera: Pteromalidae), ontwo congeneric hosts reared on two plant species under field and laboratory conditions. The plantscontain defensive iridoid glycosides that are sequestered by the hosts. Sequestration at the pupal stagediffered little between host species and, although the concentrations of iridoid glycosides in the twoplant species differ, there was no effect of diet on the sequestration by host pupae. The rate of …
Connection between temperature, larval production, virulence and geographical distribution of Rhipidocotyle parasites infecting the duck mussel, Anod…
2015
In this thesis, two bucephalid trematode parasites Rhipidocotyle campanula and R. fennica, which use the same first (Anodonta anatina) and second intermediate (Rutilus rutilus) host were studied. The aim was to investigate the effect of temperature on one of the key processes in the transmission of these parasites: 1) the emergence of cercarial larvae from A. anatina over short (1 h) and 2) long (throughout the annual cercarial shedding period, from May to October) time periods as well, as on 3) mussel survival and 4) the seasonal timing of cercarial release. In addition, the aim was to study how the cercarial shedding traits are linked to the 5) geographical occurrence and abundance of the…
Relationship between the endangered freshwater pearl mussel Margaritifera margaritifera, its salmonid host and co-infectants
2018
The relationship between the freshwater pearl mussel (hereafter FPM), Margaritifera margaritifera, and its salmonid host — pivotal for the conservation of this endangered bivalve — is characterized by a long parasitic stage (up to 11 months) and excessive host specificity. This thesis focuses on this relationship by experimentally studying the effect of FPM infection on the growth and resistance of salmonid fish and how the infection influences vulnerability of the host to other parasites and diseases, as well as how exposure of the host to other parasites affects vulnerability to FPM. Infection with FPM results in (i) reduced growth of the host, brown trout, during the parasitic period. Gl…
Effect of glochidia infection on growth of fish : freshwater pearl mussel Margaritifera margaritifera and brown trout Salmo trutta
2019
AbstractEffect of freshwater mussels’ (Unionoida) glochidia on the growth of fish host has remained poorly studied. We compared the specific growth rate of the juvenile, PIT-marked brown trout (Salmo trutta) between uninfected controls to those experimentally infected (average initial intensity of infection 8000 fish−1) with Margaritifera margaritifera glochidia, kept in high and low feeding. Growth and mortality of fish were monitored for 10 months. Our hypothesis was that glochidiosis would impair the growth of fish. According to our hypothesis, infected fish gained statistically significantly less weight than the control fish throughout the experiment. A proportional increase in weight o…
Australapatemon sp. (Trematoda) infection in Valvata macrostoma and in two leech species, Helobdella stagnalis and Erpobdella octoculata
2009
The role of salmonid fishes in conservation of the endangered freshwater pearl mussel (Margaritifera margaritifera)
2016
The abundance of freshwater pearl mussels (Margaritifera margaritifera) has declined widely during the past century, and new conservation initiatives are needed. This thesis focused on the relationship between M. margaritifera and its salmonid host required for reproduction of this species. First, by exposing fish experimentally to glochidium larvae of M. margaritifera, different M. margaritifera populations were shown to demonstrate strong differences in their ability to parasitize different salmonid species. Atlantic salmon was clearly a better host for mussels in large river channels, whereas in small headwater tributaries brown trout was the best, or the only suitable, host. These findi…
Transmission and host and mate location in the fish louse Argulus coregoni and its link with bacterial disease in fish
2007
FM Matthias Bandilla osoittaa väitöstutkimuksessaan, että kirjolohen kalatäitartunnalla on selkeä yhteys Flavobacterium columnare -infektioon, joka on yksi ongelmallisimmista bakteeritaudeista suomalaisessa kalanviljelyssä tällä hetkellä. Vaikka heikko kalatäitartunta ei aiheuta kalan kuolemaa, yhdessä bakteerialtistuksen kanssa se voi olla tappava. Vastaavien vuorovaikutusten ymmärtäminen olisi tärkeää vesiviljelyn kannalta, koska erilaisten mikrobien aiheuttamien tautien ja loisten yhteisesiintyminen kalanviljelylaitoksella on ennemminkin sääntö kuin poikkeus.Kalatäi (Argulus coregoni) on pääasiassa lohikaloilla esiintyvä äyriäispintaloinen, jonka levinneisyys ulottuu koko pohjoiselle vyö…