鼢鼠对天然草场危害程度的调查

为了进一步掌握高原鼢鼠对天然草场产草量的危害程度,海北州结合2003年春季灭治高原鼢鼠的工作,对同宝牧场天然草场进行了全面的调查了解.调查在一定的面积内以捕尽法,详细了解鼢鼠的数量、雌雄比例、怀胎仔数和对草场产草量的危害程度等情况.     

鼢鼠对天然草场危害程度的调查

<正> 为了进一步掌握高原鼢鼠对天然草场产草量的危害程度,海北州结合2003年春季灭治高原鼢鼠的工作,对同宝牧场天然草场进行了全面的调查了解。调查在一定的面积内以捕尽法,详细了解鼢鼠的数量、雌雄比例、怀胎仔数和对草场产草量的危害程度等情况。     

化隆县草地鼠虫危害调查

1997～1998年对化隆县草场上发生的鼠虫危害进行了调查研究,发现5大类草场都有害鼠和蝗虫分布;其中,在山地草甸和山地草原上较多.全县鼠害草场面积22506hm2,虫害草场面积21986hm2;高原鼢鼠和高原鼠兔是优势害鼠,狭翅雏蝗、小翅雏蝗和红翅皱膝蝗是优势害虫.高原鼠兔密度为2.5只/hm2,高原鼢鼠为3只/hm2;蝗虫平均密度为21头/hm2.     

化隆县草地鼠虫危害调查

１９９７￣１９９８年对化隆县草场上发生的鼠虫危害进行了调查研究,发现５大类草场都有害鼠和蝗虫分布,其中,在山地草甸和山地草原上较多,全县鼠害草场面积２２５０６ｈｍ＾２,虫害草场面积２１．９８６ｈｍ＾２,高原鼢鼠和高原鼠兔是优势害鼠,狭翅雏蝗和红翅皱膝蝗是优势害虫。高原鼠兔密度为２．５只／ｈｍ＾２。高原鼢鼠为３只／ｈｍ＾２;蝗虫平均密度为２１头／ｈｍ＾２。     

夏河县天然草地害鼠分布及防治调查

本文根据气候、地貌、草场类型、经济效益等特点对夏河县天然草地上主要危害鼠种及其分布情况和危害情况进行了简单的调查。调查结果显示:夏河县天然草场上主要危害鼠为仓鼠科鼢鼠亚科的高原鼢鼠和鼠兔科的高原鼠兔,危害面积达16.42万hm2,占全县草场总面积的32.75%,并针对鼠害发生情况,提出了一些防治措施。     

黑河场牧东北鼢鼠和高原鼠兔的分布及其危害

<正> 为了探索高原鼠兔和东北鼢鼠(以下简称鼠兔和鼢鼠)在同一地区气候条件下,对不同草场植被、土壤的危害,以便控制鼠害,保护草场。我们于1980年6～9月有在若尔盖县黑河牧场对鼠兔和鼢鼠进行了初步调查,现将结果汇报于后。     

药物防治高原鼢鼠的几个重要环节

药物防治高原鼢鼠的几个重要环节甘肃省天祝县草原工作站李春涛高原鼢鼠（Ｍｙｏｓｐａｌａｘｂａｉｌｅｙｉ）属啮齿目仓鼠科鼢鼠亚科，俗称瞎老，是一种长年营地下穴居生活的害鼠。在天祝地区主要集中分布在海拔２７００～３２００米之间的山地草甸草场和海拔２８００～...     

甘南州人工捕捉高原鼢鼠弓箭法演变与效果对比

本文对甘南草原地下害鼠高原鼢鼠人工捕捉弓箭法的几种方式演变进行了详细阐述。同时,通过在相同的鼠害危害草场进行现场对比试验,获得了最佳人工捕捉弓箭安置方法,为今后大面积防控高原鼢鼠提供可靠的人工捕捉弓箭方法。     

门源县天然草场高原鼢鼠繁殖性能研究

采用弓箭捕获法对门源县开然草场高原鼢鼠(Myospalax baileyi)的繁殖性能进行了调查研究.结果表明:鼢鼠的繁殖期在4月下旬至5月底,此时的雌雄比例为1:0.64,受胎率为82.2%,平均胎仔数4只左右.建议灭治时间为4月20日至5月底.     

气象因子对高原鼢鼠种群数量的影响

高原鼢鼠是青藏高原地区主要的啮齿动物种类之一,了解其种群数量与气象因子的关系对高原鼢鼠种群消长规律及生物多样性的维持具有重要意义。2013-2016年对高原鼢鼠种群密度进行了研究,利用Pearson相关分析以及典范对应分析对高原鼢鼠种群密度以及扰动区草地生物量与7个气象因子的相关性进行了分析。结果表明,高原鼢鼠种群密度及草地生物量总体呈下降趋势,且高原鼢鼠种群密度与双子叶植物生物量呈显著正相关(P0.05)。温度和降水量对高原鼢鼠种群数量以及生物量有较大影响,其中年平均气温和年平均最低气温与高原鼢鼠种群密度显著相关(P0.05),另外,高原鼢鼠种群密度与日照时数关系密切。气象因子主要通过对高原鼢鼠食物的影响而对其产生间接影响。     

高原鼢鼠栖息地的植被特征

对高原鼢鼠种群不同发展阶段下植被的群落特征进行了为时３年的研究。结果表明,植物种的多样性、植被的闰我度和地下生物量均表现为随鼠群数量的增另和作用时间的工而增加,群落的平均高度则因低矮植物的增加而有所下降,在一定条件睛,高原鼢鼠与植被相互作用可在某种状态下取得平衡并保持稳定。在地下生物量的组成上,直根和根茎的总量在地下生物量中所占比重保持相对稳定,但在鼠群发展初期,直根所占比重较小,而根茎所占比重较     

Real-timeqPCR检测鸡胚中贝氏隐孢子虫方法研究

为检测鸡胚中贝氏隐孢子虫,本研究根据GenBank公布的贝氏隐孢子虫和原鸡18SrRNA基因序列设计针对贝氏隐孢子虫的特异性引物,并以贝氏隐孢子虫卵囊基因组DNA为模板,建立检测贝氏隐孢子虫SYBRGreen实时荧光定量PCR（Real—timeqPCR）方法,同时对贝氏隐孢子虫在鸡胚中培养7d后尿囊膜和尿囊液样品中虫体DNA进行检测。结果表明,建立的SYBRGreenreal—timeqPCR方法可特异性检测到贝氏隐孢子虫,建立的标准曲线线性关系良好（R2=0．998）,卵囊基因组DNA检测阈值为10个卵囊,重复检测结果显示试验重现性较好。该方法成功检测到尿囊膜和尿囊液中虫体DNA。本研究建立了快速、特异的定量检测鸡胚中贝氏隐孢子虫real—timeqPCR方法,可用于对贝氏隐孢子虫在鸡胚中繁殖规律分析和抗隐孢子虫药物筛选等研究。     

2株贝氏隐孢子虫鸡源分离株对雏鸡的致病性比较

为了解不同地区鸡源贝氏隐孢子虫的致病特点,对收集到的郑州、林州两地区鸡源贝氏隐孢子虫卵囊经雏鸡传代扩增纯化后,分别以1×106个卵囊量接种3日龄罗曼公雏鸡,从其排卵囊情况、临床症状和病理学变化比较了2个分离株的致病情况。结果表明:2个隐孢子虫分离株均主要引起雏鸡呼吸道症状和法氏囊炎病变;接种雏鸡均于感染后第4天开始排卵囊,林州株和郑州株排卵囊持续期分别为23 d和13 d;排卵囊高峰期均为感染后第8~12天。雏鸡感染2个地区鸡源贝氏隐孢子虫分离株后,排卵囊量及排卵囊规律存在差异。     

鸭源贝氏隐孢子虫对鸡的致病性

设计3个不同剂量的鸭源隐孢子虫试验感染2日龄雏鸡,通过临床症状、增重、排卵囊规律和法氏囊指数及寄生器官组织扫描电镜观察,证实贝氏隐孢子虫160万个卵囊感染即可引起明显的呼吸道症状,发病鸡增重显著降低,法氏囊严重萎缩。贝氏隐孢子虫致病程度和排卵囊规律与感染剂量相关,主要病变表现呼吸道病变和法氏囊炎症。     

Experimental infections in domestic ducks with Cryptosporidium baileyi isolated from chickens

Oral inoculation of 13 ducks (Anas platyrhynchos) with 1 x 10(6) Cryptosporidium baileyi oocysts produced patent infections but no clinical signs of disease. Intratracheal inoculation of 13 ducks with 1 x 10(6) C. baileyi oocysts produced only mild clinical signs of respiratory disease, no deaths, and gross lesions of airsacculitis in only three ducks. The distribution of developmental stages of C. baileyi in ducks was similar to that observed in experimentally infected chickens and turkeys. Results of this study indicate that ducks are more resistant to experimentally induced respiratory cryptosporidiosis caused by C. baileyi than are chickens and turkeys.     

贝氏隐孢子虫鸡胚和雏鸡增殖模型筛选抗隐孢子虫药物试验

为探讨复方磺胺对甲氧嘧啶、磺胺二甲基嘧啶、地克珠利和阿奇霉素4种药物对鸡胚和雏鸡人工感染模型中鸡源贝氏隐孢子虫的作用,筛选有效防治隐孢子虫药物,采用鸡胚培养和人工感染雏鸡模型,分别以各组鸡胚发育状况、鸡胚中卵囊量、雏鸡精神状态、排卵囊规律、体质量变化、发病率、死亡率等为观察指标,考察这4种药物对隐孢子虫的作用。结果显示,使用复方磺胺对甲氧嘧啶、磺胺二甲基嘧啶、地克珠利、阿奇霉素组鸡胚中虫体数分别为阳性对照组的15.05%、88.71%、77.42%、68.82%。复方磺胺对甲氧嘧啶可缓解人工感染雏鸡隐孢子虫病临床症状,感染雏鸡发病率降低20%,死亡率降低13.13%,且可使排卵囊强度降低。结果表明,复方磺胺对甲氧嘧啶以一定剂量连续使用一定时间对雏鸡贝氏隐孢子虫病有潜在治疗作用。     

Performance and oocyst shedding in broiler chickens orally infected with Cryptosporidium baileyi and Cryptosporidium meleagridis

To study effects of experimental cryptosporidiosis, broiler chickens were infected per os with 5 x 10(5) oocysts of Cryptosporidium baileyi and Cryptosporidium meleagridis. In the first experiment, chickens were infected with oocysts of C. baileyi at the age of 7, 14, and 21 days. In the second experiment, chickens were infected with oocysts of C. baileyi, C. meleagridis, or both cryptosporidial species at the age of 7 days. Although clinical signs of infection were apparent, neither final live weight nor mortality was significanty influenced in chickens infected with a single Cryptosporidium species. In chickens infected with C. meleagridis, the growth retardation was observed in the 2-wk period after infection. The compensatory growth, however, started when the oocyst shedding had ceased. The number of oocysts in excreta specimens of chickens infected with C. meleagridis was two to three times lower than in excreta of chickens infected with C. baileyi. Chickens infected with both C. baileyi and C. meleagridis (5 x 10(5) oocysts of each) had significantly lower final live weight and worse feed efficiency than chickens of other groups. Concurrent infection did not influence individual C. baileyi or C. meleagridis oocyst shedding.     

Interaction of reovirus and Cryptosporidium baileyi in experimentally infected chickens

No clinical signs, gross lesions, or increased mortality were observed in specific-pathogen-free chickens orally inoculated at 5 days of age with Cryptosporidium baileyi, reovirus 2035, reovirus 2408, or combinations of these agents. Weight gain of chickens inoculated with only reovirus 2408 was depressed 0-8 days postinoculation (PI) (P less than 0.01) but not for the 21-day period PI. Weight gain of chickens inoculated with only reovirus 2035 was not affected. Cryptosporidium baileyi infection significantly depressed weight gain 8-14 days PI but not for the entire 21-day period PI. Weight gain of chickens infected with both C. baileyi and reovirus 2035 was significantly depressed 0-14 days PI and for the entire 21-day period PI. Dual infection with C. baileyi and either reovirus appeared to promote shedding of both agents. Cryptosporidia were found principally in the rectum 2-10 days PI and in the bursa of Fabricius 6-10 days PI. Reovirus infection did not cause any microscopic lesions and did not modify lesions caused by C. baileyi infection.     

Renal Cryptosporidiosis (Cryptosporidium baileyi) in specific-pathogen-free chickens experimentally coinfected with Marek's disease virus

Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.     

Identification of the Cryptosporidium isolate from chickens in Japan by sequence analyses

The Cryptsosporidium isolate from chickens in Japan by Itakura et al. is not yet accurately identified because of several discrepancies in phenotypic features. We attempted to identify this isolate by analyzing the partial sequences of the 18S rRNA, COWP and HSP70 genes. The chicken isolate showed nearly 100% homology in each gene with C. baileyi, but less than 91% homology with C. meleagridis. In addition, these genes were classified into the same cluster with C. baileyi other than C. meleagridis by phylogenetic analysis. From these results, the Cryptosporidium isolate from chickens in Japan is considered to be one of the strains of C. baileyi.