Climatic variation is an important driver of avian life history and population dynamics. Climate change models predict increased variability for many regions and to predict the effects on species, we need to examine how their life history characteristics influence their response to climate. I studied how environmental conditions influenced the ecology of white-tailed (Lagopus leucura) and rock ptarmigan (L. mutus) in tundra habitats of the southern Yukon Territory. Although sympatric in the study area, breeding territories were generally segregated, with white-tailed ptarmigan selecting steep, rocky slopes at higher elevations and rock ptarmigan preferring lower elevation sedge meadows. For both species, cold spring temperatures delayed the onset of breeding, resulting in smaller clutch sizes and fewer hatched young per female. However, delayed breeding led to a stronger reduction in these rates for rock ptarmigan, suggesting a lower resilience to extend reproductive effort in colder years. White-tailed ptarmigan were also more likely to re-nest following failure and had higher daily nest survival, both of which contributed to greater annual productivity compared to rock ptarmigan. Annual adult survival showed the opposite pattern to productivity as rock ptarmigan survival was 24 percent higher than white-tailed ptarmigan. This finding suggested a reproduction-survival trade-off exists for the two species, which may be driven by differing susceptibility to environmental factors in the region. Life history theory predicts that if the likelihood of future breeding opportunities is low, individuals should increase current reproductive effort, which may explain why white-tailed ptarmigan have longer breeding seasons and higher reproductive effort under unfavourable climatic conditions. Population models showed that growth rates (λ)were approximately stable for rock ptarmigan (λ=1.01), but declining for white-tailed ptarmigan (λ=0.96). Simulations showed that warmer spring temperatures over the next few decades would elevate λ by ~0.05 for both species, but the extent of increase in λ may be reduced with more variable spring conditions. Population growth will also depend on how changing winter conditions influence survival for each species. Model simulations suggest that if juvenile and adult survival are positively correlated, rock ptarmigan would be more resilient to severe years that simultaneously depress reproduction and survival.

Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors that mediate host-responses to pathogens. In mammals, TLR ligands promote cellular activation and the production of cytokines. Several TLR ligands have been employed prophylactically for the control of bacterial or viral diseases in the mouse model. However, the TLR-mediated responses in chickens have not been well described. Importantly, the utility of TLR agonists for the control of viral pathogens, such as avian influenza virus (AIV), has not been fully explored in chickens. To this end, the studies described in this thesis characterized the kinetics of in vivo responses in chickens to the TLR4 ligand lipopolysaccharide (LPS) and the TLR21 ligand CpG ODN. It was demonstrated that both of these ligands induced the up-regulation of several immune system genes in the spleen, including those associated with pro-inflammatory and antiviral responses, as well antigen presentation. By harnessing the immunostimulatory properties of TLR ligands, it was also demonstrated that the prophylactic administration of either poly I:C (a TLR3 ligand), LPS or CpG ODN may confer immunity to a low pathogenic avian influenza virus, as determined by a reduction in both oropharyngeal and cloacal virus shedding in infected birds. Furthermore, transcriptional analysis of genes in the spleen and lungs identified interleukin (IL)-8, interferon (IFN)-α and IFN-γ as correlates of immunity. In conclusion, TLR ligands may modulate several aspects of the chicken immune system to induce an anti-viral state, thereby conferring immunity to AIV.

Many countries, including Nepal, have been affected with highly pathogenic avian influenza (HPAI) outbreaks. There have been human mortalities in some countries and large numbers of poultry either died or were culled due to HPAI. The overall objective of this thesis was to improve our understanding of the epidemiology and economics of avian influenza (AI), and particularly HPAI, in Nepal. We determined the seroprevalence of and risk factors for AI virus antibodies presence in ducks in Kathmandu, Nepal. The estimated true prevalence of AI viruses (AIV) antibodies was 27.2% [95% Confidence Interval (CI): 24.6- 29.5]. Age of the ducks was identified as the only risk factor for AIV seropositivity. Ducks older than one year were more likely to be seropositive compared to ducks less than six months of age [Odds Ratio= 2.17 (95% CI: 1.07- 4.39)]. This study provided baseline information about seroprevalence of AIVs in Kathmandu that will benefit further research to differentiate the subtypes of AIVs circulating in Kathmandu. We also evaluated alternatives to the current control program (CCP) for HPAI in Nepal. The considered alternatives were: (i) absence of control measures (ACM) and (ii) vaccinating 60% of the domestic poultry flock twice per year. Cost-benefit analysis approach was used to evaluate the economic feasibility of the programs. In terms of the benefit-cost ratio, our findings indicated that there is a return of 1.96 dollars for every dollar spent in the CCP compared to ACM. The net present value of the CCP versus ACM was US$ 989,918. The vaccination program yielded a return of 2.41 dollars for every dollar spent when compared to the CCP. The net present value of vaccination versus implementing the CCP was US$ 13,745,454. These results support a continued investment into the CCP rather than ceasing to implement government regulated control measures and suggest that vaccination may be an even better control alternative. In summary, our studies have highlighted the value of epidemiologic and economic analysis in research of AI. Our results are expected to lead to an improved understanding and awareness of AI in Nepal and to formulation of better control strategies.

No description available.

Those who are interested in the public mood, including politicians and economists, comment that the public are becoming ever more sceptical about many things, but health risk information should not be one of them. If health risk information is perceived by the public as ‘just another scary story’, or ‘more of the same we heard last month’, then the ability of risk messages to convey urgency and recommend action could be greatly diminished; the ‘cry wolf’ scenario becomes more real every time a threat appears in the media but fails to materialise. This thesis explores how avian influenza, (H₅N₁), as a health risk category, has been reported and represented in the New Zealand media. By analysing avian influenza-related items in four New Zealand newspapers over a six-year period, 2002-2008, and by comparing results with those found in a U.S. study by Dudo, Dahlstrom & Brossard (2007), this thesis explores the dominant themes and discourses the media drew upon when reporting the health threat of avian influenza. In addition, data from four focus groups sessions was analysed for the purpose of exploring public perceptions of health risk messages and the influence of the media on those perceptions. This thesis was situated within a constructionist epistemology, and employed a mixed-methods methodology with content, thematic and textual analyses. Risk communication theories and models, media conventions of agenda-setting and framing, and sociological concepts informed how the topic of health risk communication was operationalised. The analysis of the focus group data explored how the participants discussed the threat of H₅N₁; how they constructed concepts of personal and community risk, what role, if any, they attributed to the media in their construction and how they positioned themselves in regards to illness and contagion. The focus group analysis revealed that three dominant themes - risk, media and ‘othering’ – represented how the focus group participants talked about the risk of avian influenza. These and several sub-dominant themes shared similarities to those found in the newspaper analysis. Whilst initial discussions seemed to indicate a nonchalant attitude towards the risk of avian influenza, the many topics and themes that characterised the way the participants discussed the risk between them, showed that they had thought about the personal consequences of a possible health risk, and had formed strong opinions about many facets of that risk. Results from the newspaper analysis largely mirrored those of the above U.S. study, and showed that the New Zealand media favoured episodic over thematic framing; sensationalising the reporting of avian influenza, whilst providing little in the way of scientific and contextual information. Moreover, the analysis showed that, when reporting health risks, media templates are well established. The analysis of the focus group data revealed that the participants wanted media health risk messages to be clear, concrete and factual. However, this desire for messages that communicate certainty about risk, which is, by definition inherently uncertain, raises questions about the very nature of risk communication. Findings of this thesis suggest that future risk communication research should focus, not on how the media are reporting health risks, but how the public conceptualise risk, construct it in times of crisis and evaluate their ability to control it.

The golden-winged warbler (Vermivora chrysoptera) inhabits lower elevations on reclaimed surface mines in Kentucky, an indication of recent range expansion in this imperiled species. In 2004 and 2005, I compared breeding habitat between the golden-winged warbler and blue-winged warbler (V. pinus) in eastern Kentucky at landscape, territory, and nest site scales. Distance to forest edge averaged 38 m for the golden-winged warbler and 33 m for the blue-winged warbler. Maximum territory size averaged 1.5 ha for the golden-winged warbler and 2.1 ha for the blue-winged warbler. The golden-winged warbler occurred at higher elevations (up to 912 m) than the blue-winged warbler (up to 693 m). Golden-winged warblers occurred on flatter slopes when coexisting with bluewinged warblers. A higher percentage of grass cover occurred in golden-winged warbler territories where blue-winged warblers were absent compared to territories of either species where the two coexisted. Golden-winged warblers coexisting with blue-winged warblers were more often found in shrub cover than when they established territories in absence of blue-winged warblers. Management for the golden-winged warbler should focus on enhancement of transition zones between forest edges and open grasslands, especially at higher elevations.

No description available.

Surveillance of domestic poultry flocks for antibodies against avian influenza and Newcastle disease to detect and differentiate between these diseases is very important. The ability to determine if the detected influenza virus antibodies belong to one of the reportable H5 or H7 subtypes is imperative. These two major viruses are continually responsible for economic loss in poultry industries all over the world. Current serological methods of detection are an effective means of detecting antibody responses to these viruses, however continually investigating improved methods of surveillance is important. Development of a serological assay using Luminex technology which involves the use of recombinantly generated influenza A nucleoprotein, hemagglutinin H5, hemagglutinin H7, and Newcastle disease nucleocapsid proteins bound to Magplex beads allowed for the simultaneous detection of antibodies against these proteins that matches the efficiency of past methods while maintaining high levels of specificity and overall accuracy. Assay development took the form of two connected projects beginning with construction of an assay that operated in duplex, detecting antibodies against influenza nucleoprotein (AIV-NP) and Newcastle disease nucleocapsid protein (APMV-1-NC). Once optimized, the second half of development involved expansion of the assay to include detection of H5 (AIV-H5) and H7 (AIV-H7) subtypes, as well as the addition of internal assay quality controls to monitor assay performance over time. Assay thresholds and overall performance of both of these functional assays were evaluated using large quantities of field and experimental sera from chickens and turkeys to maximize specificity and overall accuracy.

There is a growing interest in assessing the neurotoxic potential and endocrine disrupting properties of perfluoroalkyl compounds (PFCs). Several studies have reported in vitro and in vivo effects related to neuronal development, neural cell differentiation, pre- and post- natal development and behaviour. PFC exposure altered hormone levels (e.g. thyroid hormone, estrogen, and testosterone) and the expression of hormone-responsive genes in mammalian and aquatic species. Hormone-mediated events are critical in central nervous system development and function, especially those controlled by thyroid hormones (THs). The studies presented in this thesis are the first to assess the effects of PFCs on primary cultures of neuronal cells in two avian species; the domestic chicken (Gallus domesticus) and herring gull (Larus argentatus). The following TH-responsive genes were examined using real-time RT-PCR: type II iodothyronine 5’-deiodinase (D2), D3, transthyretin (TTR), neurogranin (RC3), octamer motif binding factor (Oct-1), and myelin basic protein (MBP). Several PFCs were shown to alter mRNA expression levels of genes associated with the TH pathway in avian neuronal cells. It was determined that short-chained PFCs (<8 carbons) altered the expression of TH-responsive genes to a greater extent than long-chained PFCs (≥8 carbons). Although several significant changes in mRNA expression were observed in TH-responsive genes following PFC exposure in chicken embryonic neuronal (CEN) cells (Chapter 2), there were fewer changes in herring gull embryonic neuronal (HGEN) cells (Chapter 3). The mRNA levels of D2, D3, TTR, and RC3 were altered following treatment with several short-chained PFCs in CEN cells. Oct-1 and RC3 expression were induced following treatment with several short-chained PFCs in HGEN cells. These studies are the first to report that PFC exposure alters mRNA expression in primary cultures of avian neuronal cells and provide insight into the possible mechanisms of action of PFCs in the avian brain.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 166-191). / Microfiche. / xiii, 191 leaves, bound ill. 29 cm