A study of brain injury in New Zealand sea lion pups : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand

Roe, Wendi Dianne

A study of brain injury in New Zealand sea lion pups : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand

dc.contributor.author	Roe, Wendi Dianne
dc.date.accessioned	2012-05-04T04:51:02Z
dc.date.available	2012-05-04T04:51:02Z
dc.date.issued	2011
dc.description.abstract	The New Zealand sea lion (Phocarctos hookeri) is a threatened species endemic to New Zealand. The majority of breeding in this species occurs on the Auckland Islands in the sub-Antarctic, and recent population estimates indicate that pup production is declining. Trauma is a significant cause of mortality in New Zealand sea lion pups, and much of this is believed to be caused by adult and subadult males, that bite, crush, shake and throw young pups. In this thesis, a number of techniques are used to determine the role played by traumatic brain injury in the mortality of NZ sea lion pups. The findings of gross necropsy examinations show that pups have numerous lesions indicative of traumatic brain injury, including skull fractures and subdural haemorrhages, and that pups die due to crushing and impact injuries. Although some pups have gross lesions considered in human paediatric medicine to be indicative of shaking injury, detailed histological and microbiological studies of sea lion pups show that most of these are associated with meningitis due to Klebsiella pneumoniae. This bacterium is a common cause of pup mortality. Immunohistochemical techniques are used to demonstrate that axonal injury is common in sea lion pups, but show that shaking is not a common mechanism of this pathological process. Instead, most axonal injury is found to be due to hypoxia-ischaemia, and evidence that raised intracranial pressure has occurred is comparatively common in dead pups. The combined findings of histological and immunohistochemical studies suggest that lesions such as optic sheath haemorrhage, intracranial subdural haemorrhage, spinal sub-meningeal haemorrhage, and optic nerve axonal injury could be caused by pertubations to vascular, intra-ocular, intracranial and subarachnoid pressure rather than being a direct result of trauma as is proposed in shaken baby syndrome.	en
dc.identifier.uri	http://hdl.handle.net/10179/3272
dc.language.iso	en	en
dc.publisher	Massey University	en_US
dc.rights	The Author	en_US
dc.subject	Phocarctos hookeri	en
dc.subject	Hooker's sea lion	en
dc.subject	New Zealand sea lion	en
dc.subject	Sea lion pups	en
dc.subject	Sea lion mortality	en
dc.subject	Auckland Islands	en
dc.subject	Sea lion diseases	en
dc.subject	Klebsiella pneumoniae	en
dc.subject	Meningitis	en
dc.title	A study of brain injury in New Zealand sea lion pups : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand	en
dc.type	Thesis	en
massey.contributor.author	Roe, Wendi Dianne	en
thesis.degree.discipline	Animal Science	en
thesis.degree.grantor	Massey University	en
thesis.degree.level	Doctoral	en
thesis.degree.name	Doctor of Philosophy (Ph.D.)	en