Publication Date:
2020-10-28
Description:
An up to date survey indicates that about 194 species of fish, have been found to be infected with microsporidia. In this work two types of microsporidia were found to be infecting the smelt, Osmerus eperlanus from the Elbe river. They are G. hertwigi Weissenberg 1911 and P. ladogensis Voronin 1978.
Monthly samples of smelt ranging in length from 11 till 25 cm, were collected between July 1985 and May 1986 at stations (19 till 31a) between Cuxhaven and Hamburg.
In April 1986, additional samples of smelt were collected from the Eider and Ems rivers.
0-group smelts ranging from 3 till 10 cm length were also collected in July 1985 and in March and May 1986.
The developmental stages, spore morphology, developmental cycles and Pathogenicity of the two microsporidia were studied with both the light and electron microscopes. New findings about P. ladogensis were made. An analysis of monthly samples indicated a size-dependent variation in infection prevalence. Both seasonal and regional differences in infection prevalence were observed. Infection prevalence seems to be related to water-temperature and spawning stress. The highest prevalences were recorded in summer. The relation between prevalence and some stockspecific factors is discussed.
Up to date information on microsporidia infecting fish, their distribution, Pathogenicity as well as their commercial importance have been reviewed.
Type:
Thesis
,
NonPeerReviewed
Format:
text
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