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Item Development of evidence-based strategies to control Brucella spp. in dairy herds in Henan Province, China : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Epidemiology at Massey University, Manawatu, New Zealand(Massey University, 2025-03-25) Wang, YuBrucella spp. remains a significant challenge in China, affecting the dairy industry and public health despite decades of voluntary control measures. This thesis aims to address key knowledge gaps in diagnosis, epidemiology, and disease impact of Brucella spp. in dairy herds to inform evidence-based control strategies in Henan Province, China. A scoping review of 61 studies (2004-2022) characterized the epidemiological landscape, revealing that B. abortus biovar 3 predominated 85.8% of Brucella spp. isolates recovered from dairy cattle in China. Considerable heterogeneity was observed in prevalence estimates and Brucella spp. isolation across provinces. These findings guided subsequent investigations into diagnostic accuracy, biosecurity practices, disease impact, and financial analyses. To enhance diagnostic accuracy, a cross-sectional study evaluated the diagnostic performance of four serological tests in Henan dairy herds. Using a novel Bayesian latent class model, optimal cut-off values were established for fluorescence polarization assay and competitive ELISA, estimating test sensitivity (69.7%-89.9%) and specificity (97.1%-99.6%). These findings provide a foundation for improving brucellosis diagnostic strategies. Beyond diagnosis, an assessment of farm biosecurity practices and stakeholder motivations was conducted using a structured questionnaire. Two distinct clusters of dairy herds were identified. Cluster 1, characterized by medium (400-1000) to large (>1000) herd sizes and higher educational levels, showed better adherence to proper biosecurity practices than Cluster 2. Stakeholders prioritized disease impacts and economic losses, highlighting the need for integrating these into the brucellosis control programs. To address this knowledge gap about disease impact, a longitudinal study estimated the effects of Brucella seroconversion on key production indicators. The annual incidence of seroconversion of brucellosis was 13.1% (95% CI: 10.9, 15.6) at the cow level. Seroconverted cows exhibited a reduction in daily milk yield (3.2 kg/day, 95% CI: 2.4, 4.0), elevated somatic cell counts, and increased pregnancy loss (relative risk: 4.26, 95% CI: 3.17, 5.73), compared to that of consistently negative cows. These findings provided essential epidemiological insights into the seroconversion of Brucella spp. and its implications on three essential dairy productivity outcomes. Building on these epidemiological insights, a financial analysis estimated the direct annual costs of Brucella infection at 78.9 Chinese Yuan (CNY) per animal and 4,019 CNY per infected cow. Among the three evaluated interventions (vaccination, test-and-culling, and test-and-culling plus vaccination), vaccination was the most cost-effective, yielding a benefit-cost ratio of 5.84 (95% CI: 4.34 – 7.42) and a net present value of 408.2 thousand CNY over ten years. Overall, this thesis integrates epidemiological, diagnostic, biosecurity, and financial analyses to inform evidence-based brucellosis control in Henan dairy herds. These findings could support farm stakeholders and policymakers in improving the control of Brucella spp. in Henan dairy herds, contributing to broader brucellosis control efforts in China.Item Effects of operating a solar air heater on the indoor air quality in classrooms during the winter : a case study of Palmerston North primary schools : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Building Technology at Massey University, Auckland, New Zealand(Massey University, 2020) Wang, YuSchools are densely populated places, where children spend a large amount of their time. The indoor air quality (IAQ) in classrooms impacts students’ health, academic outcomes and school absences (Borras-Santos et al., 2013; Mi et al., 2006; Shendell, Prill, et al., 2004; Smedje and Norbäck, 2000; Taskinen et al., 2007). Three New Zealand (NZ) studies have found low ventilation rates, low temperature levels, high relative humidity (RH) levels and high carbon dioxide (CO2) levels during the winter months in NZ primary schools (Bassett and Gibson, 1999; Cutler-Welsh, 2006; McIntosh, 2011). These results show a need to improve the indoor environment in NZ schools during the winter. NZ school hours, from 9 am to 3 pm, are well aligned with the optimum solar radiation and classrooms lend themselves to heat from solar energy. A project was undertaken to investigate if operating a roof-mounted solar air heater (SAH) could improve the classroom IAQ during the winter. This two-year crossover project was undertaken in four Palmerston North (PN), NZ primary schools in 2013 and six PN, NZ primary schools in 2014. These consisted of the four schools participated in 2013 plus two additional schools. In each school, two adjacent classrooms with similar construction characteristics and population characteristics participated in this project. The two adjacent classrooms were randomly assigned either to a treatment group (SAH installed and operated) or to a control group (SAH installed but not operated). The main objective of this project was to investigate the change in levels of the classroom temperature, RH, CO2, and ventilation rate from when a roof-mounted SAH was operating (treatment) and was not operating (control). Resulting from operating the roof-mounted SAH, the temperature in treatment classrooms was on average 0.5 °C higher than in the control classrooms, when both the control and treatment classrooms had the same heater use. When the control and treatment classrooms achieved the same temperature, the heater use in the treatment classrooms was 27% less than the heater use in the control classrooms. Across all schools, CO2 levels in the treatment classrooms were on average 96 ppm lower than in the control classrooms. In five out of 10 schools (50%), the levels of CO2 in the treatment classrooms were lower than in the control classrooms. Only in one treatment classroom did the ventilation rate meet the NZ Ministry of Education recommended level of 4 air changes per hour. Overall, operating a roof-mounted SAH played a positive role in increasing the temperature and ventilation rate in classrooms during the winter. However, there was not sufficient airflow to satisfy the ventilation requirements. Future research should investigate the impact of operating a SAH on the school ventilation and temperature considering increasing the SAH outlet air volumetric flow rate and keeping the outlet air temperature around 18 °C to bring more heated air into classrooms.