The epidemiology of Theileria orientalis Ikeda type in New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Sciences, Massey University, Palmerston North, New Zealand

Abstract

Listed in 2020 Dean's List of Exceptional ThesesThe research presented in this thesis was primarily conducted to document and understand the Theileria orientalis Ikeda type epidemic in New Zealand from 2012 onwards. The thesis summarises the epidemiology of the initial outbreak, presents the results of a prevalence study conducted by the Ministry for Primary Industries in 2013, presents and analyses the common history, haematology and biochemistry changes associated with acute T. orientalis infection, uses different modelling techniques to analyse the spatial-temporal effects on the epidemic, to predict the likely extent of the T. orientalis epidemic and to project the likely effects of global warming on the ecology of Haemaphysalis longicornis, the only competent vector for T. orientalis Ikeda type in New Zealand. In addition, two observational field studies were conducted, the first was a cross-sectional study to investigate the vertical trans-placental transmission of T. orientalis infection from dam to calf and the second was a longitudinal study to investigate the temporal dynamics and effects of T. orientalis infection on haematocrit, production and reproduction in three commercial New Zealand dairy herds