A Study on the Transmission of Oesophagostomum dentatum and Hyostrongylus rubidus among Outdoor Reared Pigs in Denmark

This study was carried out to obtain basic information on the transmission of Oesophagostomum dentatum and Hyostrongylus rubidus in outdoor reared pigs in Denmark. Eighteen 10 weeks old worm-free pigs were allocated into 3 groups of 6 pigs each. In May, all pigs were turned out on the same parasitologi-cally naive pasture, and after 2 weeks the pigs in groups 2 and 3 were experimentally infected with 10,800 O. dentatum and 8,700 H. rubidus infective larvae, respectively. Pigs in group 1 served as non-infected controls. All pigs were reared together on the experimental pasture for further 134 days until slaughter in October. Strongyle egg counts, differentiation of infective larvae at species level, serum pepsinogen, and herbage larval infectivity were monitored at regular intervals throughout. Both strongyle species established in the originally parasite-free pigs (group 1) and cross infections were established in group 2 and 3. The pigs were exposed to steadily increasing herbage infectivity of both species of strongyles. At the end of the experiment, geometric mean worm burdens of O. dentatum in groups 1,2 and 3 were 1202, 6136 and 1431 respectively, the burden in group 2 being significantly higher (p<0.05) than that of the 2 other groups. The geometric mean worm burdens of H. rubidus in groups 1, 2 and 3 were 4907, 3679 and 5246 respectively, showing no significant differences between groups.     

野生牧草混播组合的经济评价

1993～1995年在天山北坡利用野生豆科和禾本科草进行的放牧,刈割和刈牧兼用等不同利用方式的混播组合试验,其生长和经济状况优于单播,为野生牧草资源开发利用提供了一定的借鉴。     

Transmission of Sarcoptes scabiei in Swine by Fomites

Transmission of sarcoptic mange by fomites was investigated by placing mange-free piglets in pens for either fixed or variable periods of time during the first six days following removal of mange infected swine. Transmission occurred in pigs with as little as 24 hours exposure to fomites. Clinical signs of pruritis and focal erythematous skin lesions developed in various pigs from four and a half to 13 weeks after exposure. Pigs with the longer exposure developed clinical signs more rapidly than those with a shorter exposure. Four of six pigs developed a chronic form of the disease characterized by thickened encrustations and scurf from which mites were readily demonstrated. The remaining two pigs developed only the pruritic form and mites were never found in numerous skin scrapings examined.     

重庆喀斯特地貌型优良牧草引种筛选试验

通过3年对29个牧草品种物候期、适应性能、产量、主要营养成分、再生性能等进行的试验研究,在酉阳县3个不同海拔高度共筛选出20个优良牧草品种,其中豆科6个、禾本科11个、其他科3个.这些牧草产量高、适应性强、营养价值高,可作为喀斯特地貌型区域人工草地建植、天然草地改良的主打草种,可进行大面积推广.     

重庆喀斯特地貌型优良牧草引种筛选试验

通过3年对29个牧草品种物候期、适应性能、产量、主要营养成分、再生性能等进行的试验研究,在酉阳县3个不同海拔高度共筛选出20个优良牧草品种,其中豆科6个、禾本科11个、其他科3个。这些牧草产量高、适应性强、营养价值高,可作为喀斯特地貌型区域人工草地建植、天然草地改良的主打草种,可进行大面积推广。     

山东和河北部分地区四种猪病的血清学调查

[目的]了解山东和河北部分地区猪瘟、猪繁殖与呼吸综合征、猪伪狂犬、猪圆环病毒病的发病情况。[方法]用间接ELISA方法对144个规模化养猪场的2 008份猪血清进行抗体水平检测。[结果]两省猪瘟、猪繁殖与呼吸综合征、伪狂犬中和（gB基因）、伪狂犬病毒野毒感染（gE基因）、圆环病毒病的抗体平均阳性率分别为：89%~92%、87%、92%~95%、33%~40%和76%。各阶段猪群的猪瘟、猪繁殖与呼吸综合征、猪伪狂犬中和（gB基因）抗体阳性率普遍较高,都在80%以上;伪狂犬野毒（gE基因）抗体阳性率在14%~90%之间,其中流产母猪的抗体阳性率最高,为90%;1~4周的仔猪圆环抗体阳性率为76%（152/199）,4~10周的保育猪的抗体阳性率最低,为67%（327/489）。[结论]这四种猪病的抗体阳性率较高,免疫猪基本能得到保护,但在个别猪场仍有发病,可能与免疫失败、新流行毒株的出现、继发感染等因素有关。提示各大猪场要针对实际情况,制定出严格的综合性防控措施。     

红池坝牧草引种试验研究

本研究旨在通过野生和栽培牧草引种试验，筛选返青早，枯黄晚，青草期长的优良草种。结果表明，已筛选出返青早，枯黄晚，青草期比当地鸭茅延长６０－８８天的草种或品种七个；返青期比当地鸭茅提早１６－１７天的草种四个，五种中旬每亩产草量比当地鸭芭高７７．８－４５５．７千克的草种五个。     

湖南省某生猪批发市场疫病传播风险评估

为评估湖南省某生猪批发市场猪群疫病的发生风险,找出可能的风险因素,便于提出针对性预防措施,采用自行设计的调查问卷,结合访谈和现场调查,对27户经营户进行了调查,并将调查结果和调运数据相结合进行了疫病传播风险定性评估。结果显示:该市场疫病传入的可能性"高",内部传播的可能性"中等",疫病传出的可能性"高"。生猪调运频次多、数量大,经纪人行为复杂,运输车辆清洗消毒不彻底是可能的风险因素。评估结果提示,应尽量减少经纪人行为影响,重点加强对运输车辆的清洗消毒。     

2018年江西及福建省新现猪急性腹泻冠状病毒的分子流行病学调查

猪急性腹泻综合征冠状病毒(Swine Acute Diarrhea Syndrome Coronavirus,SADS-CoV)是2017年在我国广东首次发现的一种可导致新生仔猪急性水样腹泻及死亡的新型冠状病毒。为调查2018年江西及福建猪群中该病毒的感染情况,试验建立了一种SADS-CoV套式RT-PCR检测方法,并调查2018年江西及福建腹泻猪只样本中SADS-CoV的流行情况。根据GenBank数据库中SADS-CoV GDS04毒株(登录号MF167434)的核衣壳蛋白(N)基因核酸序列,设计了两对特异性套式引物。以猪流行性腹泻病毒、猪传染性胃肠炎病毒、猪繁殖与呼吸综合征病毒、猪瘟病毒等病毒的基因组为模板检测引物的特异性。通过优化反应条件建立了检测SADS-CoV的套式PCR方法,用建立的套式PCR方法对2018年从江西和福建两省8个猪场采集的492份腹泻样品进行检测。应用设计的两对套式引物扩增出了650 bp和291 bp两个特异性片段。试验建立的套式PCR检测方法特异性好,只能扩增SADS-CoV,其最低检测限度为102拷贝/μL。利用所建立的方法对来自江西和福建省的492份腹泻猪临床样品进行检测,从福建猪群样品中检出了2份SADS-CoV感染,未从江西临床样品中检出SADS-CoV。试验将为SADS-CoV的临床检测提供一种套式PCR检测方法,结果表明该病毒在福建猪群而未在江西腹泻猪群中流行,将对SADS-CoV的临床诊断等具有应用价值。     

鲁豫冀交界地区重要猪病的流行病学调查

开展鲁豫冀交界地区重要猪病的流行病学调查对于控制和减少该地区重要猪病的发生具有重要意义。2016年3月—2017年10月从鲁豫冀交界地区采集了1 196份样本,采用ELISA检测试剂盒检测猪瘟（classical swine fever,CSF）、猪繁殖与呼吸综合征（porcine reproductive and respiratory syndrome,PRRS）、猪伪狂犬病（porcine pseudorabies,PR）、猪流行性腹泻（porcine epidemic diarrhea,PED）抗体及抗原。结果表明,猪瘟抗体阳性率为82.94%（496/598）,抗原阳性率为2.56%（6/234）;猪繁殖与呼吸综合征抗体阳性率为81.94%（490/598）,出现繁殖障碍性疾病的病料中抗原阳性率为20.73%（51/246）;猪伪狂犬病的g B抗体阳性率为72.78%（484/665）,g E抗体阳性率为14.59%（97/665）;PEDV抗体阳性率为47.50%（95/200）,其中免疫群体的阳性率为63.30%,未免疫群体的阳性率为35.00%。该调查结果表明,在以上地区重要猪病的免疫情况不容乐观,有待于进一步加强相关疾病的免疫工作。     

建设人工柠条草场的试验研究

针对高寒干旱自然特点,种植抗寒、抗旱、抗风沙植物柠条,建设人工柠条草场,改造改良退化、沙化、荒漠化草地.结果建成后植被覆盖率由30%提高到90%多,生物量由每公顷1 246.9kg增长到9 975.0kg,土地含沙量减少17%.同时,防风效果提高9倍,固沙固土能力提高2倍,土壤中有机质、速效N、速效K等含量显著增加,有益微生物区系和数量提高几倍或几十倍.证明人工柠条草地改造退化、沙化、荒漠化土地是行之有效的.     

我国18个省份猪源肠球菌耐药调查及分析

为研究我国猪源肠球菌的耐药情况,本研究采集18个省市猪养殖场的粪便样品836份进行了肠球菌的分离鉴定,并通过琼脂稀释法测定11种抗菌药物的最小抑菌浓度.结果 显示:从836份样品中共分离出225株肠球菌,其中屎肠球菌106株,粪肠球菌56株,小肠肠球菌34株,鹑鸡肠球菌17株,铅黄肠球菌7株,坚忍肠球菌4株,Enter...     

非洲猪瘟的流行特征和传播路线

2018年8月3日辽宁省沈阳市某猪场首次暴发非洲猪瘟疫情。为了解全球非洲猪瘟流行形势,正确认识非洲猪瘟的病原学和流行病学特征,防止非洲猪瘟在我国进一步扩散和传播,本文简明阐述了非洲猪瘟特有的病原学特征、主要感染源、传播途径以及监测技术要点,分析了需特别关注的4种传染源,供相关人员参考,以便及早根除国内的非洲猪瘟疫情,保障我国养猪业健康发展。     

Resistance to levamisole and cross-resistance between pyrantel and levamisole in Oesophagostomum quadrispinulatum and Oesophagostomum dentatum of pigs

Two strains of Oesophagostomum spp., consisting of both O. quadrispinulatum and O. dentatum, were subjected to a controlled in vivo assay for resistance to levamisole and pyrantel by comparison with susceptible isolates. One strain (LEM) was recently isolated from a commercial herd, where sows showed high numbers of strongyle eggs in faeces within 2 weeks of farrowing and following treatment with levamisole at the manufacturer's recommended dose rate 1 week before farrowing. Levamisole had been used as the sole anthelmintic for treatment for at least 7 years on this farm. Treatment with pyrantel in this herd also indicated cross-resistance to this drug. A mixed population of O. quadrispinulatum and O. dentatum of this strain was subjected to controlled in vivo assays. Faecal egg count reduction (FECR) was found to be -573.3% (P greater than 0.05) and worm count reductions (WCR) of O. quadrispinulatum and O. dentatum were estimated as 44.5% (P greater than 0.05) and 96.4% (P less than 0.001), respectively. Treatment with pyrantel showed that cross-resistance existed to this drug, with FECR of 10.4% (P greater than 0.05) and WCR of 64.5% (P greater than 0.05) and 90.7% (P less than 0.05) for O. quadrispinulatum and O. dentatum, respectively. Another strain (VJ) was isolated from another commercial pig herd, which was dosed with pyrantel citrate four times a year for at least 8 years. This strain showed resistance to pyrantel, with FECR of 43.8% (P greater than 0.05) and WCR of 65.9% (P greater than 0.05) and 49.4% (P greater than 0.05) for O. quadrispinulatum and O. dentatum, respectively. However, both species were susceptible to levamisole. Our results suggested that selection with levamisole gave rise to levamisole resistance and automatically conferred resistance to pyrantel, whereas selection with pyrantel only resulted in resistance to this drug alone. These findings are discussed in relation to the location of the two species of Oesophagostomum in the large intestine of pigs and the mode of action of this class of anthelmintics.     

我国规模猪场伪狂犬病流行状况及场间传播风险因素

猪伪狂犬病是严重危害全球养猪业的传染病。随着伪狂犬病基因缺失疫苗的出现,一些发达国家通过免疫及淘汰带毒猪,已在家猪中成功实现了伪狂犬病净化。本文结合近年来的调查和研究资料,对猪伪狂犬病的主要流行病学特征、在国内猪群中的流行概况、场间传播风险因素以及防控措施等进行了详细综述,为该病的防控和净化提出了建议。