Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus)

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dc.contributor.advisorBishop, Jacqueline Men_ZA
dc.contributor.authorNaude, Vincent Normanen_ZA
dc.date.accessioned2015-05-27T04:10:13Z
dc.date.available2015-05-27T04:10:13Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractIn the past decade African penguin (Spheniscus demersus) populations have experienced declining population sizes of > 60% in some instances. This has primarily been attributed to shifting prey availability and competition with regional purse-seine fisheries; however, possible novel threats exacerbated by diminishing population sizes and increased stress, may also be important contributors to the regional persistence of the species. These threats include the impacts of arthropod-borne blood parasites on the health of penguin populations. While parasitism of wild penguins has been poorly studied, susceptibility to infection with blood protozoa is well established in a wide range of penguin species held in captivity. This thesis assesses the prevalence of blood parasites in wild African penguins throughout the greater Agulhas-Benguela ecosystem. Using PCR-based techniques, 317 individuals were screened for the presence of known haemoparasite species of Plasmodium, Haemoproteus and Babesia across 12 breeding colonies. Babesia infection was confirmed for 60% of wild birds sampled, but methods used did not indicate infection with either Haemoproteus or Plasmodium species. Generalised linear modelling of ecological and life history parameters suggests that Babesia prevalence is primarily driven by a colony’s distance from the mainland, decreasing significantly as distance from the mainland increases. Captive birds held at the SANCOBB rehabilitation facility in Cape Town present with both Plasmodium and Babesia species, providing the positive controls for the study. The relative scarcity of Plasmodium and Haemoproteus infection in the wild may be the result of an absence of suitable vectors and/or high post mortality in the host. Alternatively, the sensitivity of the method used requires further investigation as Plasmodium infection has been confirmed previously in penguin populations using PCR-based approaches. This study provides the first baseline estimate of blood parasitism in African penguins across their breeding range, and raises the need for further research and monitoring. The results suggest that high Babesia prevalence in African penguins may be related to (1) an ecological system of chronicexposure to infection reservoirs, such as the co-occurring cormorant and gannet populations and (2) increasing anthropogenic impacts, especially in mainland colonies. Data on blood parasitism in co-occurring seabird species is required to fully elucidate their role in Babesia infection dynamics in the region. To improve understanding and facilitate timely detection of changes in blood parasite exposure, standardised methodologies are advocated to better inform the conservation management of this iconic species.en_ZA
dc.identifier.apacitationNaude, V. N. (2014). <i>Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus)</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/12924en_ZA
dc.identifier.chicagocitationNaude, Vincent Norman. <i>"Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus)."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2014. http://hdl.handle.net/11427/12924en_ZA
dc.identifier.citationNaude, V. 2014. Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus). University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Naude, Vincent Norman AB - In the past decade African penguin (Spheniscus demersus) populations have experienced declining population sizes of > 60% in some instances. This has primarily been attributed to shifting prey availability and competition with regional purse-seine fisheries; however, possible novel threats exacerbated by diminishing population sizes and increased stress, may also be important contributors to the regional persistence of the species. These threats include the impacts of arthropod-borne blood parasites on the health of penguin populations. While parasitism of wild penguins has been poorly studied, susceptibility to infection with blood protozoa is well established in a wide range of penguin species held in captivity. This thesis assesses the prevalence of blood parasites in wild African penguins throughout the greater Agulhas-Benguela ecosystem. Using PCR-based techniques, 317 individuals were screened for the presence of known haemoparasite species of Plasmodium, Haemoproteus and Babesia across 12 breeding colonies. Babesia infection was confirmed for 60% of wild birds sampled, but methods used did not indicate infection with either Haemoproteus or Plasmodium species. Generalised linear modelling of ecological and life history parameters suggests that Babesia prevalence is primarily driven by a colony’s distance from the mainland, decreasing significantly as distance from the mainland increases. Captive birds held at the SANCOBB rehabilitation facility in Cape Town present with both Plasmodium and Babesia species, providing the positive controls for the study. The relative scarcity of Plasmodium and Haemoproteus infection in the wild may be the result of an absence of suitable vectors and/or high post mortality in the host. Alternatively, the sensitivity of the method used requires further investigation as Plasmodium infection has been confirmed previously in penguin populations using PCR-based approaches. This study provides the first baseline estimate of blood parasitism in African penguins across their breeding range, and raises the need for further research and monitoring. The results suggest that high Babesia prevalence in African penguins may be related to (1) an ecological system of chronicexposure to infection reservoirs, such as the co-occurring cormorant and gannet populations and (2) increasing anthropogenic impacts, especially in mainland colonies. Data on blood parasitism in co-occurring seabird species is required to fully elucidate their role in Babesia infection dynamics in the region. To improve understanding and facilitate timely detection of changes in blood parasite exposure, standardised methodologies are advocated to better inform the conservation management of this iconic species. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus) TI - Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus) UR - http://hdl.handle.net/11427/12924 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/12924
dc.identifier.vancouvercitationNaude VN. Prevalence and drivers of blood parasitism in African penguins (Spheniscus demersus). [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/12924en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherZoologyen_ZA
dc.titlePrevalence and drivers of blood parasitism in African penguins (Spheniscus demersus)en_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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