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To develop better control strategies for Cooperia oncophora a detailed understanding of the population dynamics is desirable. To achieve this, aspects of the life cycle have been studied in a series of experiments, including the free-living and the parasitic phases. To investigate the development from egg to third stage larvae, faeces containing C. oncophora eggs gathered from different donor animals were incubated at different constant and variable temperatures as well as under natural conditions in the field. To examine the survival of C. oncophora third stage larvae they were kept under similar conditions as for the development experiments. Based on the results at constant temperatures, parameters were calculated for a model to simulate the effect of temperature during the free-living phase of this nematode. A further experiment was conducted over an 11 month period to investigate the effect of host age and previous exposure on the establishment rate of third stage larvae in 3 groups of young calves. Two groups received a high or low dose of trickle-infection and the third remained as an uninfected control group. At lower temperatures the development rate and success from egg-third stage larvae were both low but increased with higher temperatures. At 8°C 50% development was reached in 56 days with a success rate of 5.5% compared to 5 days and 26.4% respectively at 32°C. The highest development success rate of 37.4% was observed at 28°C. For larval survival, the median survival was 512.2 days at 8°C and decreased to 6.4 days at 37°C. Both development and survival were significantly (p<0.05) influenced by the host animal from which the faeces were sourced. Utilising these parameters in a model provides a useful tool to further understand the effect of temperature on the free-living stages. The establishment rate of C. oncophora in the trickle-infected groups declined rapidly compared to the control group but was not significantly different (p>0.05) to the control g

Background: Neospora caninum is a parasite that causes disease, largely in cattle and dogs. It is a disease of significant interest within New Zealand due to its association with bovine abortion. The economic impact of bovine abortion justifies the development of a bovine vaccine against N. caninum. Aim: To develop and optimise diagnostic procedures for the detection of Neospora from a variety of blood and tissue samples and to isolate a New Zealand strain of Neospora caninum. Methods: A local strain of Toxoplasma gondii and an imported Neospora caninum strain, Nc-Liverpool, were used to optimise tachyzoite growing conditions in bovine endothelial (BE) cells and Vero host cell cultures. A serum study using 112 tissue culture flasks was performed to determine whether foetal bovine serum or horse serum supplemented media provided the optimal growing conditions for Nc-Liverpool tachyzoites. Nc-Liverpool tachyzoites were also used to determine the optimal growth period between passage, and harvest for cryopreservation and cryopreservation conditions. Percoll gradients were also tested using Nc-Liverpool tachyzoites. A known Neospora positive canine sample and murine tissues infected with Toxoplasma, were used during the development of the immunohistochemical diagnostic technique. Antibody concentrations and incubation temperatures were tested to reduce cross-reactivity and increase specific stain intensity. Immunohistochemistry was performed on sections of all tissue samples used for N. caninum isolation and experimentally infected murine tissue. Several PCR techniques were developed, the final PCR used being a combination of the different techniques, which produced a 250kb band. PCR-3 used the NF6/GA1 primer combination for Neospora detection and TF6/GA1 for Toxoplasma detection, additional Mg2+ and an annealing temperature of 55°C were required. Whole tissue was processed via DNA elution whereas cell culture and Percoll purified tachyzoites were used following crude l