动物副黏病毒感染与对策思考

尼帕病毒(Ni V)和亨德拉病毒(HeV)属于副黏病毒亚科的亨尼帕病毒属的成员。Ni V和HeV感染引起新的两种重要的人兽共患传染病。有关APMV-1(NDV)的发病和流行以及病原学研究认为APMV-1不断发生演化,新的基因型不断产生,对不同宿主的致病力不断变化,病毒感染的宿主谱不断扩大。本文简要介绍两种新的人兽共患传染病和APMV-1对鹅、鸭、猪的感染研究现状,就APMV-1宿主感染谱与演化加以分析,思考新的动物副黏病毒病防控对策。     

非洲猪瘟防控的经验和误区

自从2018年8月我国报告首例非洲猪瘟疫情以来,经过3年多的艰难探索,我们面对非洲猪瘟疫情从最初的恐惧和束手无策,到现在的精准清除和“与狼共舞”,疫情防控从被动应对进入到常态化管理和无疫小区建设阶段;非洲猪瘟可防可控的预测得到了实践证明。但是由于我国幅员辽阔,养猪模式多样,疫情防控水平参差不齐;非洲猪瘟疫情零星散发的风险持续存在。下面就我们的观察和调查,对近年来非洲猪瘟防控上的一些经验和误区进行简要分析。     

空气负氧离子对鸡胚和雏鸡生长发育的影响

将星杂288鸡种蛋960枚随机分为4组,进行3周孵化试验,各组空气负氧离子浓度分别为200000、100000、50000和40个/cm3。再取孵出的雏鸡120只随机分为4组,进行6周饲养试验,所设负氧离子浓度分别为100000、50000、25000和30个/cm3。结果表明:(1)200000和100000个/cm3负氧离子有助于胚胎的生长发育,能提高种蛋的孵化率;(2)50000个/cm3负氧离子可降低雏鸡料肉比和死亡率,并能促进雏鸡的生长发育,改善雏鸡的某些血液生理生化指标;(3)25000个/cm3以上的负氧离子对孵化和育雏的空气环境有一定净化作用。     

Experimental infection of Black Belly and INRA 401 straight and crossbred sheep with trichostrongyle nematode parasites

Compared to INRA 401 lambs reared in France, Black Belly (BB) lambs reared in Guadeloupe (F.W.I.) were highly resistant to both primary and secondary experimental infection with Haemonchus contortus. To investigate this huge inter-breed difference, a nucleus flock of BB was constituted, and experiments were conducted to: (i) confirm this difference in lambs born in France, (ii) check whether it was similar for Trichostrongylus colubriformis and Teladorsagia circumcincta, and (iii) find out whether this difference was age-related. Forty BB lambs, 84 F1 lambs (BB siresxINRA 401 ewes) and 88 INRA 401 lambs born in two cohorts were used in an experimental design involving three host breeds, both genders and two age-groups (3.5- and 7-month-old when first infected). The limited availability of BB lambs made the study incomplete. Infection consisted of the administration of two doses of 10,000 infective larvae of one of the nematode species, separated by an anthelmintic treatment and an interval of 1 week before the second dose was administered. Fecal egg counts (FECs) were done on Days 28 and 35 after each infection; ewe lambs of the INRA 401 and F1 breeds were necropsied, the worm burden was established, the length of the female worms measured and the eggs in utero counted. For H. contortus and T. colubriformis, the FEC was lower in the BB than in the INRA 401 lambs, and the FEC found for the F1 lambs was intermediate. For T. circumcincta, only data for the F1 and INRA 401 lambs were available, and the FECs for these breeds were the same. In all three breeds, the FEC determined after the second dose was significantly lower than that found after the first dose in the ewe lambs, but not in the ram lambs. Infecting the lambs when they were 7- instead of 3.5-month-old significantly lowered egg excretion of both parasites in the F1 (P<0.0001), but not the INRA 401 lambs. Worm numbers in the F1 and in the INRA 401 ewe lambs confirmed the FEC data, many F1 lambs being free of T. colubriformis. The H. contortus female worms were shorter and had fewer eggs in utero in the F1 than in the INRA 401 lambs. A higher proportion of T. circumcincta was at the fourth larval stage in the F1 lambs. In conclusion, the BB breed is much more resistant than INRA 401 to H. contortus, with the F1 lambs being more like the BBs after the second dose. This difference was also found for T. colubriformis and, to a lesser extent, for T. circumcincta.     

合理调整免疫程序 科学实施动物免疫

现阶段我国动物疫病的防控主要采取免疫的策略,现行的免疫方案中存在着一些问题,各地区和养殖企业应结合本地区和/或本场的实际情况,制定出具有更强的指导性、可操作性和自己特色的免疫方案,更好地指导动物的免疫工作。     

Using a Bayesian belief network to aid differential diagnosis of tropical bovine diseases

The examination of presenting signs has always played an important role in the diagnosis of diseases in animal populations. In the case of diseases of tropical cattle, such expertise is often scarce and confined to those experts with many years of experience. To capture, conserve and disseminate such valuable expert knowledge remains a key challenge to the application of knowledge-based systems in veterinary medicine. In this communication, we explore the use of a Bayesian belief network to quantify expert opinion with a view to estimating the likelihood of various diseases in the presence and absence of certain signs. Information was elicited from a panel of 44 experienced veterinarians to provide the response matrix of 27 signs associated with 20 commonly occurring diseases in sub-Saharan cattle. Using this prior information, estimates of the probability of certain signs occurring with each disease were calculated from which the Bayesian belief network was able to propagate the posterior probability of each of the diseases based on the observed signs. The method as an aid in making diagnosis is discussed. It is recognised that such an approach is but one strand in the process of arriving at a diagnosis. For ease of use and accessibility, the approach has been converted into the software program CaDDiS (Cattle Disease Diagnosis System) which is available for consultation on the World Wide Web.     

Selection of immunodominant mimics of IROMP-99 of rabbit Pasteurella multocida from a random 12-peptide library

A random 12-peptide library was used to screen immunodominant mimics of 99kDa iron-regulated outer membrane protein (IROMP-99) of rabbit Pasteurella multocida. In the present study, expression of IROMPs of rabbit P. multocida strain C51-12 were analyzed by SDS-PAGE, and Western blot to determine the specificity of rat antiserum antibodies against IROMP-99. Only IROMP-99 whose expression was induced under iron-restricted conditions was detected on nitrocellulose paper. The phage display library was screened with rat normal and IROMP-99-specific antiserum. The positive phage clones were identified using enzyme-linked immunoadsorbent assay (ELISA) and inhibition assays for their reactivity to the antiserum. Out of the 18 randomly selected positive clones that showed higher reactivity to rat antiserum, only ten clones efficaciously inhibited binding of rat antisera to IROMPs and their displayed peptides were determined. Alignment using DNAStar-MegAlign software, results showed that motif WHxTxP was highly conserved among nine clones, only clone A7 had no obvious linear homology with either. Our findings suggest that the motif WHxTxP could be an immunodominant mimic epitope of IROMP-99 of rabbit P. multocida strain C51-12.     

不同断奶日龄仔猪血清代谢物水平的变化

本试验研究了不同断奶日龄仔猪血清代谢物水平的变化。试验设１７日龄断奶、２１日龄断奶、２８日龄断奶、３５日龄断奶４个处理组,每个处理３个重复,每个重复１窝,定时采血。结果表明,１７、２１日龄断奶组仔猪血糖浓度显著低于３５日龄断奶组（Ｐ〈０．０５）,在断奶后２～３周时间内,以１７日龄断奶组仔猪血糖浓度波动最大;４个不同断奶日龄组之间仔猪血清尿素氮浓度没有显著差异;与３５日龄断奶组比,１７日龄断奶仔猪血     

大豆黄酮对奶牛血清钙、磷及葡萄糖水平的影响

本研究选用40头胎次、产奶量、泌乳期相近的中国荷斯坦奶牛随机分成4组(n=10),试验组奶牛日粮中分别添加45、60和75mg/kg大豆黄酮,在试验前及试验开始后第10天、第20天和第30天颈静脉采血,测定4组奶牛血清钙、磷和葡萄糖水平。结果表明:与对照组相比较,试验1组中血清钙、磷和葡萄糖变化均不显著(P>0.05);试验2组仅血清钙在第30天时显著高于对照组(P<0.05);试验3组第10天和20天时血清钙水平显著高于对照组(P<0.05),第30天时血清钙水平极显著高于对照组(P<0.01),而血糖水平仅第30天显著高于对照组(P<0.05)。