Landscape features influence genetic structure of black-tailed prairie dogs (Cynomys ludovicianus)

Black-tailed prairie dogs (Cynomys ludovicianus) currently live in metapopulations in the parts of their range where plague, caused by the bacterium Yesinia pestis, has invaded. Prairie dogs are highly susceptible to the pathogen, with most animals within towns dying during Y. pestis outbreaks. A review of population genetic studies of prairie dogs demonstrates considerable differentiation between prairie dog towns. Despite declines and fluctuations in size of prairie dog populations, they continue to harbor considerable genetic variation. This results from continual dispersal and gene flow, likely along low-lying drainages that connect towns. When combined with estimates of population size, the landscape genetic approach described here will provide precise estimates of dispersal and gene flow, in addition to evaluation of long-term stability of prairie dog metapopulations.     

The harvest of the freshwater crayfish <Emphasis Type="Italic">Astacus leptodactylus</Emphasis> Eschscholtz in Turkey: harvest history,impact of crayfish plague,and present distribution of harvested populations

This review focuses on the present distribution of populations of the crayfish Astacus leptodactylus that are harvested in Turkey. It also examines the history of this harvest and the impact that crayfish plague has had on them. Crayfish plague, caused by the fungus-like organism, Aphanomyces astaci Schikora, 1906, is a severe parasite of freshwater crayfish and has caused a lot of damage to A. leptodactylus populations in Turkey since 1984. Turkey was the largest provider of A. leptodactylus to Western Europe from 1970 (or possibly earlier) until 1986. For example, the peak production was reached in the early 1980s, with over 5,000 tonnes being exported in 1984. On the other hand, as a result of the crayfish plague the harvest of A. leptodactylus was reduced severely in most populations in Turkey after 1985. The harvest was only 320 tonnes in 1991. After the occurrence of crayfish plague in Turkey, in order to increase crayfish production uncontrolled A. leptodactylus stockings have been carried out in many waterbodies throughout Turkey. These introductions have caused an increase in the number of A. leptodactylus populations, but exploitation of A. leptodactylus is still under the pressure of the plague, although there has been a steady increase in crayfish production in recent years. The harvest increased to 2,317 tonnes in 2004. Fortunately, among those populations affected by crayfish plague, large amounts of A. leptodactylus can still be harvested from three lakes, ?znik (Bursa), E?irdir (Isparta) and Çivril (Denizli). Thus, it seems that A. leptodactylus has a degree of resistance to crayfish plague. It is therefore interesting to investigate the resistance of A. leptodactylus caught from these populations to crayfish plague.     

Persistence of Gunnison’s prairie dog colonies in Arizona, USA

Although the five species of prairie dogs (Cynomys spp.) are recognized as important components of grassland ecosystems in western North America, they have experienced major population declines due to poisoning, outbreaks of sylvatic plague, recreational shooting, and habitat conversion. From May 2000 to October 2001, we investigated 270 colonies of Gunnison’s prairie dog (Cynomys gunnisoni) in Arizona. Because these colonies were classified as active in previous surveys (1987, 1990-1994, 1998), we were able to examine their persistence. Most (70%) of the colonies became inactive between the initial and recent surveys, with colony extinctions spanning our study area. Colony persistence was positively associated with the persistence of the nearest neighboring colony but was not associated with major vegetation type, distance to nearest neighboring colony, or initial size of the colony. The amount of area occupied by individual colonies varied between surveys, sometimes dramatically. We found little evidence that the reduction in active colonies was due to poisoning, recreational shooting, or habitat conversion. Rather, direct and indirect evidence suggest plague is the primary factor negatively impacting Gunnison’s prairie dog populations in Arizona. Currently, there is no way to control or prevent plague outbreaks in Gunnison’s prairie dog populations. To mitigate the effects of localized plague outbreaks on the overall population of this species, we suggest that Gunnison’s prairie dog be reintroduced to public lands throughout its historical range.     

榆林地区动物间鼠疫风险调查分析

鼠疫是鼠疫耶尔森菌借鼠蚤传播为主的甲类传染病,系广泛流行于野生啮齿类动物间的一种自然疫源性疾病,易感动物主要为啮齿动物,人类一旦感染对其生命健康存在极大的危害。榆林地区虽然目前未发生动物间鼠疫疫情流行,但与榆林地区接壤的内蒙、宁夏等地近年来相继报道出现动物间鼠疫疫情传播情况。本文通过对鼠疫的流行特点和传播途径进行论述,对榆林地区目前面临的形势及风险进行研判,并进一步对本地人间鼠疫防控工作进行深入调查研究,为逐步建立系统性的动物间鼠疫监测工作提供科学依据。     

黄骅市东亚飞蝗大发生原因分析与治理对策

深入分析了黄骅市蝗区东亚飞蝗的发生特点、发生趋势及其原因,并提出了相应的治理对策。     

2018年青海省鼠疫流行病学分析

分析了2018年青海省鼠疫监测结果,为制定鼠疫防控措施提供科学依据。应用Excel软件分析2018年青海省鼠疫监测、鼠疫疫源地调查和人间鼠疫病例数据,采用描述性流行病学方法进行分析。结果表明:2018年青海省未发生人间鼠疫疫情,全省各地区未检出鼠疫F1抗体血清,未分离出鼠疫菌。结论近年来青海省动物间鼠疫每年均有发生,虽然本年度未检出阳性血清和分离出鼠疫菌,但不能排除有些地区存在动物间鼠疫流行的可能性,鼠疫流行风险依然存在。     

2012年青海省国家级鼠疫监测点监测结果分析

分析2012年青海省4个国家级鼠疫监测点的监测结果,为进一步制定鼠疫预防控制措施提供科学依据.按《全国鼠疫监测工作方案》和《青海省鼠疫监测方案》的要求,对监测点主要宿主动物和媒介昆虫进行病原学和血清学监测;采用路线法调查旱獭密度、五米夹线法调查小型啮齿动物种类和数量分布;对检获的宿主动物体的媒介昆虫进行分类鉴定和计数.结果表明4个监测点的平均旱獭密度为0.039只/hm2,早獭平均蚤指数为0.021,染蚤率 2.13％,共检测各类动物材料938份,检出鼠疫菌2株,检测动物血清536份,IHA阳性2份.     

国家级鼠疫监测点格尔木市2007-2012年鼠疫流行病学特征分析

分析青海省格尔木市境内鼠疫流行特征,探讨鼠疫流行态势,为今后鼠疫防治工作提供科学依据。格尔木市作为青藏铁路沿线的国家级监测点按照《青藏铁路鼠疫防治技术方案》、《青藏铁路防治工作方案》和《全国鼠疫监测方案》实施监测工作,汇总2007—2012年格尔木市境内的鼠疫监测报告,应用描述流行病学方法进行分析。格尔木市2007—2012年动物间鼠疫时有发生,共分离鼠疫菌1株;检出鼠疫F1抗体阳性血清1份。格尔木市动物间鼠疫流行仍旧活跃,鼠疫防治态势依然严峻。。     

鸭瘟病毒TK基因及其编码蛋白的生物信息学分析

运用生物信息学方法,对鸭瘟病毒TK基因的基本元件和TK蛋白的理化性质、结构、功能进行分析。明确了TK基因启动子、转录起始位点、编码区P、olyA的位置;发现TK蛋白的二级结构以α螺旋为主,属于混合型蛋白,在结构和功能上与疱疹病毒胸苷激酶高度相似。生物信息学分析结果说明,鸭瘟病毒TK蛋白具有疱疹病毒胸苷激酶的活性,鸭瘟病毒TK基因可能为鸭瘟病毒的非必需毒力基因。     

明清时期江淮地区的蝗灾探析

从对传统农业社会经济破坏程度来看,蝗灾是仅次于水旱灾害的一种高危害的灾种。本文以灾害学、历史学等学科的方法,比较系统地探讨了明清时期江淮地区蝗灾的几个阶段以及时空分布特点和影响因素。