Chytridiomycosis, an emerging infectious disease of amphibians in South Africa / C. Weldon

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dc.contributor.author Weldon, Ché
dc.date.accessioned 2009-02-18T06:14:11Z
dc.date.available 2009-02-18T06:14:11Z
dc.date.issued 2005
dc.identifier.uri http://hdl.handle.net/10394/860
dc.description Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2005.
dc.description.abstract The sudden appearance of chytridiomycosis, as the cause of amphibian deaths and population declines in several continents suggests that its etiological agent, the amphibian chytrid fungus Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. Efforts were directed to determine the occurrence of chytridiomycosis in Africa, whether the disease had been introduced into South Africa in recent years and how wild frog populations were affected by infection. A chytridiomycosis survey of 2,300 archived and live specimens involving members of the Pipidae family in sub-Saharan Africa, as well as a number of unrelated frog species in South Africa was conducted by histological diagnosis of skin samples. The epidemiological evidence indicated that chytridiomycosis has been a stable endemic infection in southern Africa for 23 years before any positive specimens were found outside Africa. The occurrence of chytridiomycosis in South Africa can be described as widespread both in terms of geographical distribution and host species and generally infection is not associated with adverse effects at the individual or population level. It was proposed that the amphibian chytrid originated in Africa and that the international trade in the African clawed toad Xenopus laevis that commenced in the mid 1930s was the means of dissemination. A risk assessment of the X. laevis trade demonstrated that chytridiomycosis could spread through this pathway and culminated in the development of a management protocol to reduce the risks of spreading disease through this animate commodity. Initial comparative genetic analysis of B. dendrobatidis strains isolated from South African frogs with a global set of 35 strains, suggests that analysis of a more geographically diverse set of southern African strains is needed before this line of argument can support or reject the "out of Africa" hypothesis.
dc.publisher North-West University
dc.subject Chytridiomycota en
dc.subject Batrachochytrium dendrobatidis en
dc.subject Chytridiomycosis en
dc.subject Disease en
dc.subject Origin en
dc.subject Epidemiology en
dc.subject Africa en
dc.subject Amphibian declines en
dc.subject Xenopus laevis en
dc.title Chytridiomycosis, an emerging infectious disease of amphibians in South Africa / C. Weldon en
dc.type Thesis en
dc.description.thesistype Doctoral

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    This collection contains the original digitized versions of research conducted at the North-West University (Potchefstroom Campus)

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