Search results for "madot"

Redescription and phylogenetic analysis of the type species of the genus Panagrellus Thorne, 1938 (Rhabditida, Panagrolaimidae), P. pycnus Thorne, 19…

2021

Abstract The identity of Panagrellus pycnus, the type species of the genus Panagrellus, is discussed after studying specimens from a cultured population collected in Italy that fits the original material of the species. A new characterization is consequently provided as follows: body 0.93–1.32 mm long, lip region continuous with the adjoining body, stoma with gymnostom very reduced, pharynx with not swollen metacorpus, neck 161–203 µm long, excretory pore at level of the metacorpus, post-vulval uterine sac 99–162 µm long or 2.6–3.8 times as long as the body diameter divided in a short tubular proximal part and a long swollen distal part, vulva post-equatorial (V = 63–69), female tail conica…

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…

The occurrence of Echinorhynchus salmonis Müller, 1784 in benthic amphipods in the Baltic Sea

2015

Abstract: The acanthocephalan Echinorhynchus salmonis Müller, 1784 is a common parasite of salmonid fish, but it has rarely been reported from an intermediate host. Samples of benthic amphipods, Monoporeia affinis (Lindström), were taken from multiple, deep sites (usually below 70 m) in the Gulf of Bothnia over the course of more than a decade and examined for acanthocephalans. Overall, only 0.44% of 23 296 amphipods were infected, all with just a single worm. This prevalence is consistent with several previous reports of acanthocephalans in deep-water, benthic amphipods, but it appears low compared to that often reported for acanthocephalan species infecting littoral amphipods. Parasite oc…

Diplostomiasis ( Diplostomum spathaceum and related species).

2020

This book chapter describes various aspects of diplostomiasis caused by Diplostomum spathaceum: diagnosis, epidemiology, life cycle, transmission, developmental stages, population dynamics, effects of climate change on parasite distribution, and disease control and prevention. peerReviewed

Satamasedimenttien ekotoksikologinen riskinarviointi

2008

Transmission of Diplostomum spathaceum between intermediate hosts

2004

FM Anssi Karvonen tutki väitöskirjassaan kalojen silmän linssissä elävän Diplostomum spathaceum -imumatoloisen ekologiaa. Tutkimus tarjoaa uutta tietoa lois-isäntä -suhteiden evoluutiosta sekä perustietoa, jonka avulla voidaan suunnitella loisen torjuntamenetelmiä kalanviljelyssä. Tutkimukset ovat lisäksi osa laajempaa projektia, jossa tutkitaan D. spathaceum -loisen elinkierron ekologiaa ja evoluutiota kaikissa elinkierron vaiheissa. Sen yhtenä päämääränä on kehittää elinkierron matemaattinen malli, jonka avulla on mahdollista kehittää ekologisesti kestäviä menetelmiä D. spathaceum -loisen torjuntaan.D. spathaceum on yksi luonnonkalojen yleisimmistä loisista Suomessa ja sitä esiintyy myös …

Индивидуальность поведения рыб влияет на риск заражения паразитами [Personality influences risk of parasitism in fish]

2019

Influence of fish personality on infection rate is almost not studied. In the experiments on the young-of-the-year Oncorhynchus mykiss and cercariae of a trematode Diplostomum pseudospathaceum we tested the hypothesis that infection rate differs between more and less active (“bold” and “shy”) fish. Will individual differences in infection persist upon re-infection? Fish serve as a second intermediate host for this trematode. A positive correlation was found between the results of consecutive infections. Accumulation of parasites with successive infections leads to an aggregated distribution of D. pseudospathaceum among the hosts, affecting individual fitness and polymorphism in fish populat…

Hydraulic Habitat Structure Impacts Risk of Trematode Infection

2022

Abstract— Variability in infection rates of trematodes Diplostomum pseudospathaceum in 0+ rainbow trout Oncorhynchus mykiss under different hydraulic regimes was studied in the experimental setup with regulated flow rates and environmental heterogeneity. The average infection rate in the conditions of the current was 1.5 times less than that in the stagnant water. An increase of the flow rate from 3.2 to 11.3 cm/s did not result in lower infection rates, while the interindividual variability in the infection rate (coefficient of variation) tended to increase along with changing the still-water conditions (20%) to the high flow rate environments (40%) within the experiment. A decrease in th…

Host Developmental Stage Effects on Parasite Resistance and Tolerance.

2022

Hosts can defend themselves against parasites either by preventing or limiting infections (resistance) or by limiting parasite-induced damage (tolerance). However, it remains underexplored how these defense types vary over host development with shifting patterns of resource allocation priorities. Here, we studied the role played by developmental stage in resistance and tolerance in Atlantic salmon (Salmo salar). This anadromous fish has distinct life stages related to living in freshwater and seawater. We experimentally exposed 1-year-old salmon, either at the freshwater stage or at the stage transitioning to the marine phase, to the trematode Diplostomum pseudospathaceum. Using 56 pedigree…