Are we ready for pandemic influenza?

During the past year, the public has become keenly aware of the threat of emerging infectious diseases with the global spread of severe acute respiratory syndrome (SARS), the continuing threat of bioterrorism, the proliferation of West Nile virus, and the discovery of human cases of monkeypox in the United States. At the same time, an old foe has again raised its head, reminding us that our worst nightmare may not be a new one. In 2003, highly pathogenic strains of avian influenza virus, including the H5N1 and H7N7 subtypes, again crossed from birds to humans and caused fatal disease. Direct avian-to-human influenza transmission was unknown before 1997. Have we responded to these threats by better preparing for emerging disease agents, or are we continuing to act only as crises arise? Here we consider progress to date in preparedness for an influenza pandemic and review what remains to be done. We conclude by prioritizing the remaining needs and exploring the reasons for our current lack of preparedness for an influenza pandemic.     

转基因和基因编辑猪的研究进展

猪是重要的农业经济动物,其在遗传背景、解剖学、生理病理学、营养代谢和疾病特征等方面与人类高度相似,是农业生产性状改良、人类疾病动物模型和异种器官移植研究的重要对象。随着ZFN、TALEN和CRISPR等基因编辑技术的出现,转基因或基因编辑猪的研究取得快速发展。本文将结合当前我国转基因及基因编辑猪的研究现状,对基因编辑技术在农业生产性状改良如提高产肉量、改善肉质、提高抗病能力和建立人类疾病模型、动物生物反应器、异种器官移植等方面进行综述,以期为猪遗传改良和医学研究提供参考。     

Prevention and control of zoonoses at their source: from the Chinese perspective

Zoonoses are a significant public health concern and cause considerable socioeconomic problems globally. The emergence of severe acute respiratory syndrome (SARS), highly pathogenic avian influenza (HPAI), and Ebola virus disease (EVD) has had a significant effect on the national economy and public health in China, and other countries. This review analyzed zoonotic disease issues faced by China, and the main factors contributing to the risk of zoonotic disease. The Chinese government has devised new strategies and has taken measures to deal with the challenges of these diseases, and the prevention and control of zoonoses at their source. A strategy that is suited to China’s national conditions, is proposed.     

Chaos versus noisy periodicity: alternative hypotheses for childhood epidemics

Whereas case rates for some childhood diseases (chickenpox) often vary according to an almost regular annual cycle, the incidence of more efficiently transmitted infections such as measles is more variable. Three hypotheses have been proposed to account for such fluctuations. (i) Irregular dynamics result from random shocks to systems with stable equilibria. (ii) The intrinsic dynamics correspond to biennial cycles that are subject to stochastic forcing. (iii) Aperiodic fluctuations are intrinsic to the epidemiology. Comparison of real world data and epidemiological models suggests that measles epidemics are inherently chaotic. Conversely, the extent to which chickenpox outbreaks approximate a yearly cycle depends inversely on the population size.     

Immunotherapeutic approaches to Alzheimer's disease

Although neurodegenerative diseases such as Alzheimer's disease are not classically considered mediated by inflammation or the immune system, in some instances the immune system may play an important role in the degenerative process. Furthermore, it has become clear that the immune system itself may have beneficial effects in nervous system diseases considered neurodegenerative. Immunotherapeutic approaches designed to induce a humoral immune response have recently been developed for the treatment of Alzheimer's disease. These studies have led to human trials that resulted in both beneficial and adverse effects. In animal models, it has also been shown that immunotherapy designed to induce a cellular immune response may be of benefit in central nervous system injury, although T cells may have either a beneficial or detrimental effect depending on the type of T cell response induced. These areas provide a new avenue for exploring immune system-based therapy of neurodegenerative diseases and will be discussed here with a primary focus on Alzheimer's disease. We will also discuss how these approaches affect microglia activation, which plays a key role in therapy of such diseases.     

猪流感病毒研究进展

猪流感是猪常见呼吸道疾病之一,在世界范围内流行.患猪常续发其他疫病,导致猪死亡率增加,该病毒变异体还可跨种传播,严重影响养猪业的发展及人的健康.为此,简要介绍了猪流感的病原,比较了猪流感临床症状,分析了病毒跨种间传播致病机制的分子基础,并概述了其公共卫生意义.     

丁型流感病毒在中国的流行状况及研究进展

丁型流感病毒是继甲型、乙型和丙型流感病毒之后的一种新型正粘病毒,2011 年首次由美国从表 现出流感样症状的猪只中分离出来,并于 2016 年被国际病毒分类委员会正式命名为丁型流感病毒。目前丁型流 感病毒已广泛分布于美洲、亚洲、欧洲和非洲的数十个国家。丁型流感病毒利用牛作为其自然宿主和扩增宿主, 并定期扩散到其他哺乳动物物种,包括猪、马、羊和骆驼等。因此,丁型流感病毒具有广泛的地域分布和宽泛 的宿主范围。丁型流感病毒感染可导致牛患轻度至中度呼吸道疾病,被认 为是牛呼吸系统疾病综合征的重要关 联因子。血清学证据表明,丁型流感病毒具有感染人的潜在风险。我国研究人员于 2014 年首次在山东省的牛群 中检测到丁型流感病毒,随后,来自不同团队的研究人员分别于 2017、2021 和 2022 年报道了丁型流感病毒核 酸阳性病例。为更好地了解丁型流感病毒对我国畜牧养殖业的影响,系统综述了丁型流感病毒在我国的分布情 况和研究进展,并分析 了丁型流感病毒在我国的流行趋势及对我国畜牧养殖业的潜在威胁。     

猪流行性感冒研究进展

猪流行性感冒(Swine influenza,SI)是由猪流感病毒(Swine influenza virus,SIV)所引起的一种高度传染性病毒病,对养猪业和公共卫生具有严重隐患.文章对SI的病原及其血清型、疾病流行与分布、SI与其他疾病的关系、公共卫生意义和防制等最新研究进展进行了综述,这对进一步认识和控制该病具有重要意义.     

Synchrony, waves, and spatial hierarchies in the spread of influenza

Quantifying long-range dissemination of infectious diseases is a key issue in their dynamics and control. Here, we use influenza-related mortality data to analyze the between-state progression of interpandemic influenza in the United States over the past 30 years. Outbreaks show hierarchical spatial spread evidenced by higher pairwise synchrony between more populous states. Seasons with higher influenza mortality are associated with higher disease transmission and more rapid spread than are mild ones. The regional spread of infection correlates more closely with rates of movement of people to and from their workplaces (workflows) than with geographical distance. Workflows are described in turn by a gravity model, with a rapid decay of commuting up to around 100 km and a long tail of rare longer range flow. A simple epidemiological model, based on the gravity formulation, captures the observed increase of influenza spatial synchrony with transmissibility; high transmission allows influenza to spread rapidly beyond local spatial constraints.     

基于分层多元复合模型的广东省农田土壤有机碳高精度制图

农田有机碳库是唯一可在较短时间尺度上通过合理利用而进行适度调节的碳库,农田土壤有机碳高精度制图对进一步明析地理环境背景,提升区域土壤固碳潜力,促进碳交易、碳中和等具有重要的意义。本研究以广东省为研究区,在中大空间尺度区域综合特征分区的基础上,基于地理探测器确定农田土壤有机碳空间分异的变量结构,分区构建分层多元复合模型,根据208 503个土壤采样点数据编制研究区高精度农田土壤有机碳密度空间分布图。结果表明：耦合自然地理特征和社会经济特征,引入多距离空间聚类进行中大空间尺度综合特征分区,能够显著收敛样本离散程度,土壤有机碳样本标准偏差均值、方差均值较未分区前分别下降0.55、3.53,Moran''s I指数上升0.08。受自然环境与人为扰动双重影响,农田土壤有机碳空间变异的变量众多,且不同综合特征分区内变量结构差异较大,年均降水量、海拔高度、地形坡度等变量在不同特征分区的影响力存在显著差异,土地利用方式及土壤理化性质等变量对不同特征分区均存在较大的影响力。基于地理探测器构建的分层多元复合模型,较好地解决了中大尺度和复杂情景下土壤有机碳空间分异规律与空间突变的同步表达矛盾,抑制了多变量插值噪声增加,其综合精度较地理加权回归模型（GWRK）、径向基函数神经网络（RBFNN）和普通克里格（OK）分别提升6.45%、10.45%和7.50%。在大密度样本集支持下,综合区域综合特征分区、地理探测器、分层多元复合模型等技术手段编制的广东省高精度农田土壤有机碳空间分布图,预测结果准确,空间细节表达清晰,为编制大空间尺度的土壤有机碳分布图探索了有效路径。     

胶东半岛地区酿酒葡萄病害的发生与防治现状调查

采用田间调查结合问卷调查的方法,对山东胶东半岛地区酿酒葡萄生长期病害进行调查。结果表明:山东胶东半岛地区酿酒葡萄生长期主要病害有6种,包括炭疽病、霜霉病、白腐病、灰霉病、酸腐病以及褐斑病;其中炭疽病是主要病害,发病严重的病果率达35.63%,个别地块有绝收现象;褐斑病只在个别地块中发现;酸腐病和霜霉病在葡萄生长后期加重;炭疽病严重的地块酸腐病也严重。病害防治主要采用化学药剂防治,药剂种类以石硫合剂、波尔多液、多菌灵及福美双为主;整个生长季施药普遍在14～15次,最多可达17次。     

好氧堆肥去除畜禽粪便病原体的研究进展

近年来，非洲猪瘟、甲型H1N1流感、禽流感和新冠肺炎等疫情频发，其中甲型H1N1流感和禽流感等人畜共患病的病原体引发的疫情传播逐渐受到固体废弃物处理利用领域的关注。携带大量病原体的畜禽粪便若不能合理循环利用，会对人体健康和生态安全造成威胁。高温好氧堆肥是一种处理固体废弃物的常用方法，堆肥过程的高温阶段能够有效降低病原体数量，但仍有部分堆肥产品因病原体残留而存在安全风险。本文综述了堆肥过程对病原体的去除效果及其影响因素，探讨了堆肥产品中病原体残留的可能原因和存在的风险，并基于此提出了可以提高堆肥病原体去除效果的工艺优化方向，这将最大程度降低堆肥产品的安全风险，确保畜禽粪便堆肥产品的安全高效使用。     

Sequence homology between certain viral proteins and proteins related to encephalomyelitis and neuritis

Post-infectious or post-vaccinal demyelinating encephalomyelitis and neuritis may be due to immunological cross-reactions evoked by specific viral antigenic determinants (epitopes) that are homologous to regions in the target myelins of the central and peripheral nervous systems. Such homologies have been found by computer searches in which decapeptides in two human myelin proteins were compared with proteins of viruses known to infect humans. These viruses include measles, Epstein-Barr, influenza A and B, and others that cause upper respiratory infections. Several regions identified in myelin basic protein and P2 protein can be related to experimental allergic encephalomyelitis or neuritis in laboratory animals.     

A simple model for complex dynamical transitions in epidemics

Dramatic changes in patterns of epidemics have been observed throughout this century. For childhood infectious diseases such as measles, the major transitions are between regular cycles and irregular, possibly chaotic epidemics, and from regionally synchronized oscillations to complex, spatially incoherent epidemics. A simple model can explain both kinds of transitions as the consequences of changes in birth and vaccination rates. Measles is a natural ecological system that exhibits different dynamical transitions at different times and places, yet all of these transitions can be predicted as bifurcations of a single nonlinear model.     

Digital infrared thermography for monitoring canopy health of wheat

Computer-aided diagnosis and prognosis models have been used for management decisions in crop protection. Initial infection rate, temperature and leaf wetness are important parameters in disease epidemiology and for decision support models. So far, in-field variability and variability between fields have not been taken into account for management decisions in disease control. This study aimed at testing the use of an imaging IR thermography system as a tool for monitoring the microclimatic conditions promoting incidence and severity of diseases within wheat fields with a high spatial resolution. Experiments were conducted on the detection and differentiation of leaf wetness on a single leaf scale and a crop canopy scale (1 m²) under controlled conditions. Field studies focused on comparing ground-based and air-borne thermographic data and linking these to ground-truth data.     

Endemicity of H9N2 and H5N1 avian influenza viruses in poultry in China poses a serious threat to poultry industry and public health

The H9N2 and H5N1 avian influenza viruses (AIVs) have been circulating in poultry in China and become endemic since 1998 and 2004, respectively. Currently, they are prevalent in poultry throughout China. This endemicity makes them actively involved in the emergence of the novel lineages of other subtypes of influenza viruses, such as the well-known viruses of the highly pathogenic avian influenza (HPAI) H5N2 and the 2013 novel H7N7, H7N9 and H10N8 subtypes, thereby threatening both the poultry industry and public health. Here, we will review briefly the prevalence and evolution, pathogenicity, transmission, and disease control of these two subtypes and also discuss the possibility of emergence of potentially virulent and highly transmissible AIVs to humans.     

Site-specific management: the application of information technology to crop production

Site-specific management (SSM; also called, precision agriculture) is the management of agricultural crops at a spatial scale smaller than that of the whole field. Widespread farmer adoption of SSM practices is contingent on its economic advantage. Three criteria that must be satisfied in order for SSM to be justified are, (1) that significant within-field spatial variability exists in factors that influence crop yield, (2) that, causes of this variability can be identified and measured, and (3) that, the information from these measurements can be used to modify crop management practices to increase profit or decrease environmental impact. The objective of this paper is to review the state of SSM at the turn of the millennium and to offer some speculation as to its future course. The review is organized around the essential components of SSM listed above, i.e. measuring spatial variability, analyzing the data obtained from these measurements, using information gained from this analysis to effect changes in management practices, and determining whether the resulting benefits are worth the costs. The discussion section considers some potential effects of large-scale adoption of SSM, should this adoption occur.     

近10年景观生态学模型研究进展

对2001—2010年国内外景观生态学模型研究文献的梳理发现,景观模型研究已是景观生态学研究的热点与重点。归纳总结了当前景观生态学研究领域中景观模型的主要特点、优劣势及其应用范畴,并将景观模型归纳为空间概率模型、领域规则模型、景观过程模型和景观智能耦合模型4大类,其中景观过程模型进一步分为空间生态系统模型、空间斑块动态模型、空间直观景观模型、个体行为模型。提出当前景观生态模型研究中存在的主要问题,即数据源获取与模型间的矛盾、重模拟轻检验、生态过程对格局影响的模型研究尚为薄弱、模型尺度推绎仍未有大突破等。最后,从景观模型的有效性检验和评价、模型的尺度推绎、模型的简化和现实应用性、模型的普适性以及模型的辅助支持等方面对景观生态模型的研究未来予以展望。     

基于农户尺度的山区生态压力及其影响因素分析———以重庆市为例

生态压力反映了人类对自然界的干扰,其值的降低预示着地区的森林转型和植被恢复.基于重庆市山区1 015份问卷调查数据,采用本地生态足迹的方法来度量农户尺度山区的生态压力,并运用多元线性回归模型分析影响山区生态压力的主要因素,重点分析山区农村劳动力转移对生态压力的影响.研究发现:1)研究区人均生态压力为1.590hm~2,农户的薪柴采集活动是山区生态压力的主要来源;2)家庭总人口、非农劳动力年均工资水平、家庭农业收入、家庭拥有电器数量以及地区哑变量武隆县和巫山县对山区的生态压力产生显著影响;3)山区农村劳动力的转移确实能够降低地区的生态压力,但是在作用路径上,并不是通过减少农村劳动力的数量,而是通过提高非农劳动力的工资水平、增加农户务农的机会成本发生作用的.     

贵阳市烤烟种植大户经营模式的调查

对贵阳市6个乡(镇)种烟大户和分散农户的几种烤烟种植模式进行了调查。结果为贵阳市烤烟种植模式主要有5种:公司 职工 科技园经营、政府 公司 大户经营、多个大户合作经营、大户独立经营和分散农户经营模式,各种种植模式在栽培管理水平、烟叶质量、产量表现上均以大户种植模式优于分散农户种植模式,且以烟草公司 职工 科技园经营最好。在烤烟生产上建议限制小面积农户,控制大户,发展烤烟的适度规模化种植,有利于技术人员的管理与指导和农户的集中管理,提高烟叶的质量,实现烤烟的可持续发展。