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Biology and immunobiology of Spirometra in Western Australia

Stephanson, Jillian Marianne (1985) Biology and immunobiology of Spirometra in Western Australia. PhD thesis, Murdoch University.

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Abstract

Parasites of the genus Spirometra collected in Western Australia, were classified as s. erinacei on the basis of their host range (natural and experimental), developmental rate, morphology and host-parasite relationships.

Experimental results, in particular those from an inbred isolate, indicated that earlier workers had underestimated this species phenotypic plasticity.

Variation was associated with experimental (infection, collection, processing and examination procedures), environmental (temperature, pH and salinity), host (species, strain, age, size, sex, diet and immune status) and parasitic (age and numbers) factors.

The inbred isolate was compared with other Western Australian isolates, Spirometra from other localities in Australia and abroad, and published data on Spirometra and Diphyllobothrium. This showed that several taxonomic criteria are of limited or no value (e.g. the host range of the procercoid, plerocercoid and adult, the prepatent period, and periodicity of egg production), or of use at the specific rather than generic level (e.g. adul t neck length).

Infections with Spirometra plerocercoids evoked both humoral and cell mediated immune responses, but the plerocercoids were seldom killed by their host. With time the parasites growth rate, migratory activity, parasite-induced host weight gain, and host mortality these changes are thought to be immunologically mediated. This outcome was not markedly affected by active immunization (with live plerocercoids, plerocercoid tail antigens or secretory antigens), by infections with Taenia taeniaeforrmis or by Bacillus Calmette-Guerin, Corynebacteriwn parvum or Freunds complete adjuvant.

A slight immunosuppression (assessed in vivo), was seen in infected mice. This immunosuppression may be caused by plerocercoid secretory products, but whether it contributes to their ability to survive in a wide range of hosts could not be ascertained.

The study concluded that perhaps as few as three other forms (S. pretoriensis, Baer, 1924; S. theileri, Baer, 1924 and S. trinitatis, Cameron, 1936) are sufficiently different from the cosmopolitan form(s) of Spirometra to rank as independent species. This study does not support the view, held by some other workers, that Spirometra and Diphyllobothrium should be amalgamated. Thus the genus is clearly in need of taxonomic revision but because of the parasites variability, there is insufficient detailed data on "rare" species for a satisfactory revision at the present time.

The similarity between the Australian Spirometra and those in other localities, in particular Japan, and the absence of any records of definitive hosts among animals native to Australia, suggests that this parasite has been introduced to Australia, possibly by mans activities.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Environmental and Life Sciences
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s): Dunsmore, John and Thompson, Andrew
URI: http://researchrepository.murdoch.edu.au/id/eprint/51745
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