Coccidiosis in the kiwi (Apteryx spp.) : aspects of the pathology, epidemiology and parasite biology : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand

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Although coccidiosis was first reported in kiwi 35 years ago, there has been little published information available on this disease, and the following research presents the first in--‐depth account of coccidiosis in kiwi. In the present study, coccidiosis was found mainly in juvenile birds and affected all five species of kiwi (Apteryx spp.). Infection was common, with 13% of kiwi submitted for necropsy and 25% of droppings examined during the study period presenting evidence of coccidia. Disease may cause mortality, and coccidiosis was the primary diagnosis in 26% of kiwi with pathological evidence of infection. Clinical signs associated with disease were usually non--‐specific, and included a combination of depression, dehydration, inappetance, weight loss and diarrhoea with fresh blood or meleana. Enteric coccidiosis was the most common form identified at necropsy, with evidence of at least three separate intestinal species of coccidia in kiwi. The presence of lamina propria macromeronts and large colorectal polyps containing progametocytes suggested at least some enteric species in kiwi may be highly fecund. In addition, the life cycle of some species appears highly complex. Renal merogony and gametogony was a common finding, suggestive of a separate species of coccidia within the kidney. Visceral stages of merogony were also identified in the liver, and occasionally in the spleen and lung. It is currently unknown where gametogony occurs for these visceral forms, and whether these are obligatory parts of the life cycle of one or more coccidial species or rather aberrant presentations of those normally found in the intestine or kidney. Morphological studies confirmed that at least four of the coccidia affecting kiwi are of the genus Eimeria, and these findings were substantiated using molecular techniques targeting the internal transcribed spacer (ITS) regions of the coccidial ribosomal DNA. Molecular results showed significant sequence variability within both ITS--‐1 and ITS--‐2 regions, consistent with findings from Eimeria spp. from other hosts. Results from this research provide the foundation for future investigations into the biology of coccidia affecting kiwi, enabling sound veterinary advice for management of this disease.
This thesis comprises articles either published or yet to be published. Due to possible copyright infringement the entire full text cannot be reproduced here. If you wish to view the thesis, please access the print copy held in the Library. Chapter 2 Chapter published exactly as Morgan, K. J., Alley, M. R., Pomroy, W. E., Castro, I., & Howe, L. (2012). Enteric coccidiosis in the brown kiwi (Apteryx mantelli). Parasitology Research, 111(4), 1689-1699. doi: 10.1007/s00436-012-3008-5 Access the full text: Chapter 3 Chapter published exactly as Morgan, K. J., Alley, M. R., Pomroy, W. E., Gartrell, B. D., Castro, I., & Howe, L. (2013). Extra-intestinal coccidiosis in the kiwi (Apteryx spp.). Avian Pathology, 42(2), 137-146. doi: 10.1080/03079457.2013.776665 Access the full text: Chapter 4 Submitted version of chapter published as Morgan, K. J., Castro, I., Lopez-Villalobos, N., Pomroy, W. E., Alley, M. R., Gartrell, B. D., Howe, L. (2014). Prevalence of and risk factors for coccidiosis in kiwi between 1977 and 2011. New Zealand Veterinary Journal, 62(6), 315-320. doi: 10.1080/00480169.2014.932657 Access the full text: Chapter 5 This chapter contains information on morphology of a number of Eimeria spp. identified from kiwi [yet to be published]. Chapter 6 This chapter provides molecular evidence of Eimeria spp. from the kiwi [yet to be published].
Kiwis, Coccidiosis, Eimeria