麦红吸浆虫的灾害与成灾规律研究——Ⅱ．灾害出现的影响因子与控制

小麦吸浆虫作为小麦的重要害虫能够成灾,内在条件在于其生活隐蔽、幼虫滞育与多态性、潜伏土壤中隔年或多年羽化、种群数量增长迅速,具r型与k型生态对策的优势特性。小麦作为承灾体,对麦红吸浆虫的危害有一系列防御机制,表现出不选择性、机械抗性、生化抗性等多层次的综合抗性。种植感虫小麦品种,抽穗期与吸浆虫的羽化高峰期相吻合,是出现灾害的基本条件。在半湿润和干旱地区,小麦生态系统的自然环境因子,如地形地势、土壤、温度、降雨、光照、风、天敌,以及农业生产措施如水利工程与灌溉、品种更换、种植制度、土壤耕作、施用农药、施肥、播期等田间管理措施与水平,对麦红吸浆虫发生与暴发成灾有交互影响作用。小麦品种的抗性程度、保持土壤湿度的灌溉条件与雨量、种植制度及农田农药的施用情况是麦红吸浆虫发生与成灾的关键因子,新灌区对麦红吸浆虫的灾害应特别引起注意。麦红吸浆虫灾害发生的过程分为孕育期、潜伏期、预兆期、暴发期、持续期、衰减期、平息期7个阶段。根据灾害出现各阶段的特征,提出了控制策略与监控措施。     

Rapid diagnosis of duck plagues virus infection by loop-mediated isothermal amplification

Duck virus enteritis is a serious disease among farmed and free-living ducks (Anatidae) and a constant threat to the commercial duck industry in China. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed to rapidly detect and diagnose duck plague virus (DPV) in both farmed and wild waterfowl, and compared with polymerase chain reaction (PCR) method and real-time PCR method in accuracy, sensitivity and specificity. A set of four specific primers was successfully designed to recognize six distinct genomic sequences of UL6 protein from DPV, including one forward inner primer, one back inner primer and two outer primers. The optimum reaction temperature and time were verified to be 61.5 °C and 60 min, respectively. Comparative experiments showed that LAMP assay was a simple, rapid, accurate, sensitive and specific method for detecting DPV, and was superior to PCR assay in sensitivity and specificity for DNA amplification. In addition, challenge tests indicated the newly developed LAMP method was more sensitive for the diagnosis of DPV infection than virus isolation and PCR. LAMP assay would be a good alternative method for on-farm disease diagnosis.     

Adaptive strategies of Yersinia pestis to persist during inter-epizootic and epizootic periods

Plague is a flea-borne zoonotic bacterial disease caused by Yersinia pestis. It has caused three historical pandemics, including the Black Death which killed nearly a third of Europe's population in the 14th century. In modern times, plague epizootics can extirpate entire susceptible wildlife populations and then disappear for long time periods. Understanding how Y. pestis is maintained during inter-epizootic periods and the factors responsible for transitioning to epizootics is important for preventing and controlling pathogen transmission and ultimately reducing the burden of human disease. In this review, we focus primarily on plague in North American foci and discuss the potential adaptive strategies Y. pestis might employ to ensure not only its survival during inter-epizootic periods but also the rapid epizootic spread and invasion of new territories that are so characteristic of plague and have resulted in major pandemics and establishment of plague foci throughout much of the world.     

鼠疫疫苗研究进展

鼠疫具有高度传染性和致病性,早期的预防很重要.免疫接种是预防鼠疫的重要措施之一.传统的鼠疫疫苗包括灭活疫苗、减毒活疫苗.随着生物技术的发展,使得亚单位疫苗和核酸疫苗应运而生,并成为研究的热点.论文综述了当前鼠疫疫苗的应用现状和新型疫苗的开发研究概况.     

四川省鸭瘟病原的分离鉴定

用9～10日龄鸭胚和血清交叉中和试验从四川省七个疑似鸭瘟发病片区分离鉴定了七株鸭瘟病毒。经测定,这七个毒株与鸭瘟标准强毒AV1221F16代的血清型、抗原性一致,没有血凝特性,对氯仿敏感,属于DNA病毒;鸭胚半数致死量DELD50为10^-4.59～10^-5.92/0.2mL;本动物回归使四川麻鸭在3～7天死亡;电镜下观察成熟病毒粒子呈球形成近似球形,带有囊膜,直径150～160nm,具有疱疹病毒的典型形态结构。     

苍南县蝗虫的发生与防治

介绍了苍南县１９９１－１９９８年蝗灾发生的情况,并对引起蝗灾蝗虫的种类,发生面积,发生原因及其防治措施进行分析和论述,为今后的治蝗工作提供依据。     

兔出血症病毒西藏野毒分离株的鉴定

对西藏农牧学院分离的一株兔出血症病毒(RHDV)西藏野毒进行血凝性、特异性和致病性进行鉴定。结果表明,此株RHDV野毒血凝价高达10240以上;RHDV抗血清可特异性抑制该株病毒对人“O”型红细胞的凝集;西藏株RHDV的最小致死量为10^-5／mL,是一株具有高致病力的RHDV强毒株。