A survey of Myxosporidia in teleosts from the South-Western. coast
of England demonstrated the widespread occurrence of these parasites.
Infection in selected fish species was related to age, sex and seasonal
migration of the host.
Structural studies of Myxobolus exiguus and Myxidium incurvatum
were undertaken in order to investigate sporogenesis, parasite
development and the host-parasite interface. Of particular note was
the intimate association between parasite and host cells, the structure
of the surface layers in Myxobolus exiguus and Myxidium incurvatum,
and the occurrence of epithelioid cells in developmental stages of
Myxobolus exiguus.
Myxobolus exiguus was transmitted experimentally in mullet, and
aspects of the mode of infection, including exsporulation, were studied
in this and other species, including those with coelozoic development.
patterns. Experiments designed to simulate the gut biotope identified
the action of trypsin and mechanical fracture as important exsporulation
factors in Myxobolus exiguus. The release of spores and their dispersal
and survival outside the host were investigated, and the possible
existence of intermediate transport hosts discussed.
Pathological effects of histozoic and coelozoic myxosporidian
infection were examined in selected hosts. Fibroblastic encapsulation
of plasmodia, and hyperplasia, characterised intestinal and branchial
infections of Myxobolus exiguus in mullet, and cystic replacement of
renal tissue was associated with Myxidium giardi infection in eels.
Biliary myxosporidiosis caused chronic irritation and fibrosis of the
gall bladder wall, increased bile viscosity and discolouration.
Incidence, periodicity and severity of various Myxosporidian
infections are discussed with regard to their disease potential and
possible impact on commercially-important teleost species.
| Date of Award | 1981 |
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| Original language | English |
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| Awarding Institution | |
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The biology of marine myxosporida and an investigation into the effects of these parasites on teleosts
Tomlinson, C. N. (Author). 1981
Student thesis: PhD