The application of epidemiology in aquatic animal health -opportunities and challenges

ABSTRACT: Over recent years the growth in aquaculture, accompanied by the emergence of new and transboundary diseases, has stimulated epidemiological studies of aquatic animal diseases. Great potential exists for both observational and theoretical approaches to investigate the processes driving emergence but, to date, compared to terrestrial systems, relatively few studies exist in aquatic animals. Research using risk methods has assessed routes of introduction of aquatic animal pathogens to facilitate safe trade (e.g. import risk analyses) and support biosecurity. Epidemiological studies of risk factors for disease in aquaculture (most notably Atlantic salmon farming) have effectively supported control measures. Methods developed for terrestrial livestock diseases (e.g. risk-based surveillance) could improve the capacity of aquatic animal surveillance systems to detect disease incursions and emergence. The study of disease in wild populations presents many challenges and the judicious use of theoretical models offers some solutions. Models, parameterised from observational studies of host pathogen interactions, have been used to extrapolate estimates of impacts on the individual to the population level. These have proved effective in estimating the likely impact of parasite infections on wild salmonid populations in Switzerland and Canada (where the importance of farmed salmon as a reservoir of infection was investigated). A lack of data is often the key constraint in the application of new approaches to surveillance and modelling. The need for epidemiological approaches to protect aquatic animal health will inevitably increase in the face of the combined challenges of climate change, increasing anthropogenic pressures, limited water sources and the growth in aquaculture. TABLE OF CONTENTS: 1 Introduction 42 The development of aquatic epidemiology 73 Transboundary and emerging diseases 93.1 Import risk analysis (IRA) 103.2 Aquaculture and disease emergence 113.3 Climate change and disease emergence 133.4 Outbreak investigations 134 Surveillance and surveys 154.1 Investigation of disease prevalence 154.2 Developments in surveillance methodology 164.2.1 Risk-based surveillance and scenario tree modelling 164.2.2 Spatial and temporal analysis 164.3 Test validation 175 Spread, establishment and impact of pathogens 185.1 Identifying routes of spread 185.1.1 Ex-ante studies of disease spread 195.1.2 Ex-post observational studies 215.2 Identifying risk factors for disease establishment 235.3 Assessing impact at the population level 245.3.1 Recording mortality 245.3.2 Farm health and production records 265.3.3 Assessing the impact of disease in wild populations 276 Conclusions 317 Competing interests 328 Authors' contributions 329 Acknowledgements 3310 References 33.     

钙信号通过IP3通路对肥胖小鼠脂肪合成代谢的影响

【目的】探讨IP3信号通路是否会影响肥胖小鼠细胞内的钙离子浓度以及钙信号对肥胖小鼠脂肪代谢的作用机制,进一步了解胞内钙离子浓度变化对脂肪代谢的作用机理。【方法】用高脂日粮饲喂小鼠30d以建立肥胖模型,将肥胖小鼠分为对照组、去甲肾上腺素(NE)组、肝素组、钙组、钙+NE组和钙+肝素组,除对照组和钙组外的各药物组小鼠分别给予相应的药物处理,腹腔注射质量浓度0.1mg/mL的NE或1.5mg/mL的肝素0.2mL/(只.d);对照组和钙组同法给予等体积的生理盐水。对照组、NE组和肝素组小鼠饲喂普通日粮,钙组、钙+NE组和钙+肝素组小鼠饲喂加钙饲粮(钙含量12g/kg),小鼠共饲喂16d,期间每3d测1次体质量,17d时禁食12h,摘眼球取血后脱颈椎处死,分离血清检测其中甘油三酯(TG)、总胆固醇(TC)和高密度脂蛋白(HDL-C)的浓度,并取脂肪组织,测定附睾脂肪和肾周脂肪组织质量,分析附睾脂肪、肾周脂肪和肝脏的钙含量。通过RT-PCR法分析与脂肪生成密切相关的转录因子PPARγ、C/EBPα和脂解基因HSL及生脂基因FAS mRNA的表达水平,检测IP3受体IP3R1的mRNA表达水平。【结果】肝素和膳食钙处理对肥胖小鼠有极显著的减肥效果(P<0.01),可极显著减少体脂质量(P<0.01),降低血清中TG和TC浓度(P<0.01),而HDL-C浓度极显著升高(P<0.01),肝素和膳食钙处理肥胖小鼠的PPARγ、FAS和IP3R1的mRNA水平均极显著降低(P<0.01),HSL mRNA水平极显著升高(P<0.01),C/EBPα的mRNA水平无明显变化;NE处理对肥胖小鼠的作用效果与肝素相反,其可明显削弱减肥作用(P<0.01)。膳食钙有显著的减肥效果(P<0.01),但钙+NE组的减肥效果弱于钙组(P<0.01),钙+肝素组的减肥效果强于膳食钙的处理效果(P<0.01)。【结论】IP3通路激活可引起胞内钙离子浓度升高,脂肪蓄积增加;反之,脂肪蓄积减少。通过IP3通路,膳食钙可抑制胞内钙离子增加。     

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