Studies on protozoan parasites of small mammals

Mohamed, HA 1986, Studies on protozoan parasites of small mammals , PhD thesis, University of Salford.

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Abstract

Studies on several different protozoan parasites of small mammals, moles (Talpa europaea), bank voles (Clethrionomys glareolus), field voles (Microtus agrestis), field mice (Apodemus sylvaticus), mice, rats and rabbits are described in this study. In the mole (Talpa europaea) three parasites were studied: Elleipsisoma thornsoni, Cyclospora talpae and Trypanosoma talpae. Elleipsisoma thornsoni was described as a parasite in the red blood cells of the mole earlier this century and its identity and parasitic nature was in doubt* Electron microscopic studies conclusively showed that the parasite was an Apicomplexan and was different from other blood parasites of haemosporidians and piroplasms by the presence of a conoid. Cyclospora talpae, a coccidian in the liver of the mole, was studied by both the light and electron microscope. In histological sections, the localisation of macro- and microgametocytes in the epithelial cells of the bile ducts was investigated. The ultrastructure of the sexual and asexual stages were studied. In Trypanosoma (Megatrypanum) talpae, some preliminary aspects of its reproduction in the mammalian host and the development in haemogamasid mites was studied. This is the first recorded observation of the development of mammalian trypanosomes in mites. In these mites an isosporan-type coccidian (with developmental stages of sporogony and gametogony) was also found and described. The sporulation of oocysts was completed inside the mite's body and was typically isosporan with 2 sporocysts, each with 4 sporozoites. The second part of this study was concerned with the biology of the trypansomes of the subgenus Herpetosoma: T. microti. T. evotomys T. grosi, T. lewisi w/2, T. musculi P/2 and T. nabiasi. Cultivation of T. microti, T. evotomys and T. grosi in insect tissue culture media and their ultrastructure is reported and compared with T. lewisi and T. musculi. T. nabiasi was grown in blood agar medium. T. microti and T. musculi were grown in Microtus agrestis embryo fibroblasts to study development in vitro at 37°C of the bloodstream and reproductive forms. T. microti, T. musculi P/2 and T. lewisi w/2 were also grown for the first time in a new semi-defined, cell-free medium to study development of the mammalian forms at 37°C. The successful cultivation of Herpetosoma trypanosomes made it possible to conduct the biochemical studies, on thin-layer starch-gel electrophoresis, of six trypanosome species (T. microti, T. evotomys, T. grosi, T. lewisiw/2, T. musculi P/2 and T. nabiasi) using 13 isoenzymes. Results from 10 isoenzymes of these trypanosomes, except T. nabiasi which was available only as a weak lysate, were analysed by two computer programmes which constructed both a similarity index and a cladistic relationship. The results were in accord with the previous groupings of these trypanosomes based on observations of methods of reproduction in mammals and development in vectors.

Item Type: Thesis (PhD)
Contributors: Molyneux, DH (Supervisor)
Schools: Schools > School of Environment and Life Sciences
Funders: European Development Fund (EDF), British Council
Depositing User: Institutional Repository
Date Deposited: 30 Jun 2021 14:26
Last Modified: 27 Aug 2021 21:54
URI: http://usir.salford.ac.uk/id/eprint/61073

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