猪附红细胞体病流行病学调查及不同药物治疗效果

对保定市猪附红细胞体病进行流行病学调查,并对感染附红体断奶仔猪进行药物治疗试验.选择保定市6个县区30个不同规模的猪场和20个散养户,随机采集不同年龄阶段猪血液样品2 040份,进行直接压片镜检、血液涂片染色镜检和碘制动试验等病原学检测;选择阳性断奶仔猪进行药物治疗试验.结果保定市猪附红细胞体感染率为74.25％,不同年龄阶段的猪不同季节均可感染附红细胞体;临床治疗及体外药敏试验结果表明,贝尼尔、咪唑苯脲、盐酸多西环素、磺胺间甲氧嘧啶和土霉素对断奶仔猪附红细胞病的治疗具有较好的效果,尤以盐酸多西环素效果最佳.     

重庆地区家畜附红细胞体分子流行病学调查及危险性因素

本试验对重庆地区牛、猪和羊附红细胞体进行分子流行病学调查及危险性因素分析。在2006—2008年期间,采用鲜血压片法、姬姆萨染色法和基于16SrRNA-PCR方法,共检测了307头份牛血样,检测阳性率分别为46%、48%和11%;检测猪血样1 658头份,检测阳性率分别为63%、68%和76%;检测羊血样1 191份,检测阳性率分别为61%、70.4%和16.1%。危险性因素分析结果显示,山区牛附红细胞体感染阳性率极显著高于丘陵地区(OR=16.03,95%CI=5.47～17.11)(P<0.01),山区猪和山羊附红细胞体感染阳性率显著高于丘陵地区(猪:OR=1.38,95%CI=1.06～1.79;羊:OR=1.43,95%CI=0.54～3.82)(P<0.05)。农户散养牛和猪的附红细胞体感染阳性率极显著高于规模化养殖(牛:OR=3.2,95%CI=1.48～6.89;猪:OR=2.28,95%CI=1.79～2.89)(P<0.01)。农户散养山羊附红细胞体感染阳性率高于规模化养殖场(OR=1.19,95%CI=1.09～1.54)(P>0.05),但差异不显著。     

重庆荣昌县牛、羊附红细胞体感染情况调查及危险性因素分析

采用鲜血压片、瑞氏染色法、姬姆萨染色法和PCR法检测荣昌县牛、羊附红细胞体的感染情况,并选择比数比(OR)、相对危险性(RR)及95%可信限(95%CI)对附红细胞体病的流行进行危害性评估.结果显示:鲜血压片、瑞氏染色法、姬姆萨染色法和PCR法检测附红细胞体,牛的阳性率为33%、33%、33%和0,羊的阳性率分别为64.5%、57.3%、53.6%和11.8%.圈养羊相对于放养羊感染附红体的危险性OR= 1.27,RR=1.18,95%CI=0.91～1.53.表明在荣昌地区牛、羊存在着附红细胞体感染.     

渝西地区猪附红细胞体病感染情况调查

2003年4月～2004年3月，采用鲜血压片法对重庆西部部分定点屠宰场的屠宰肥猪、规模化猪场及散养的生长育肥猪、断奶仔猪共882（头）份血液，进行猪附红细胞体病检测，其感染率达66．55％，说明重庆西部地区猪附红细胞体病感染率较高，不同年龄阶段猪的感染率存在显著差异。     

猪附红细胞体的形态学观察方法的比较

本文通过鲜血压片镜检、瑞氏染色、姬姆萨氏染色对猪附红细胞体进行形态学方面的观察,并对三种形态学研究方法的优缺点进行评价。结果表明,鲜血压片镜检法易受温度影响,姬姆萨染色易受pH值和染色时间的影响,瑞氏染色法要防止颗粒沉积。     

猪附红细胞体PCR与光镜检测方法的比较研究

应用鲜血压片、姬姆萨染色、吖啶橙染色三种光镜检测方法以及PCR法检测猪附红细胞体,对临床20例疑似病例进行检测,比较其检出率,结果表明,鲜血压片、姬姆萨染色、吖啶橙染色以及PCR法临床检测率分别为20%、35%、50%、70%。证实PCR检测方法明显优于其它光镜检测方法。     

一例仔猪感染猪附红细胞体的诊断

为了对一例仔猪附红细胞体病做出准确的诊断,本文采用了三种血液形态学诊断方法。猪附红细胞体病形态学诊断方法包括鲜血生理盐水压片、血涂片的瑞氏和姬姆萨染色,以及在油镜下观察猪附红细胞体的形态,采用上述方法对该例仔猪附红细胞体病做出了准确的诊断,为临床治疗提供了依据。     

将乐县猪附红细胞体病流行情况调查

将血涂片用姬姆萨染色、镜检,确认猪附红细胞体阳性感染,调查将乐县猪附红细胞体病流行情况。调查发现将乐县猪附红细胞体阳性感染率夏季比冬季更高,而且有逐年上升的趋势。     

单克隆抗体间接免疫荧光(IFA)检测猪附红细胞体

为建立利用单克隆抗体检测猪附红细胞体病的间接免疫荧光(IFA)方法,用抗猪附红细胞体的单克隆抗体,对48份疑似猪附红细胞体感染的病猪猪血进行免疫荧光检测,并与血涂片镜检及PCR检测方法进行比较,结果显示IFA检测的阳性率为68.75%,与PCR检测阳性率为77.08%符合率较高,比血涂片的瑞氏和姬姆萨染色镜检阳性率高出近30个百分点;而用猪肺炎支原体、猪链球菌和猪巴氏杆菌作对照,结果均呈阴性。建立的用抗猪附红细胞体的单克隆抗体检测猪附红细胞体病的IFA特异性强,敏感性高;检测临床样品的结果准确可靠。     

猪附红细胞体DnaJ基因PCR诊断方法的建立及应用

为建立一种特异、敏感、准确的猪附红细胞体诊断技术,本试验根据GenBank上发表的猪附红细胞体全基因组(NC-015153.1)中的DnaJ基因序列设计合成了一对特异性引物,建立了猪附红细胞体DnaJ基因PCR诊断方法,进行了特异性和敏感性试验,并与姬姆萨染色镜检方法进行了临床应用比较.结果,猪附红细胞体DnaJ基因PCR诊断方法扩增片段大小为868 bp(GenBank登录号为;JN247670),与GenBank中(NC_015153.1)同源性为99％,该方法扩增不出犬新孢子虫、牛附红细胞体、犬附红细胞体等基因片段,最低检测猪附红细胞体DNA量为124 fg/μL,通过对53份猪血液样本的检测,并与血液涂片姬姆萨染色镜检比较,说明建立的PCR诊断方法具有特异、敏感、准确等优点,完全适用于猪附红细胞体的诊断.     

猪附红细胞体50S核糖体基因PCR检测方法的建立及应用

根据GenBank上最新发布的猪附红细胞体基因组序列(NC-015155)设计一对引物,并以吉林省延边地区猪附红细胞体基因组DNA为模板,建立猪附红细胞体50 S核糖体基因PCR诊断方法,通过特异性、敏感性及临床应用试验验证,快速准确的检测出猪附红细胞体.试验结果显示,建立的猪附红细胞体PCR诊断方法扩增片段大小为10...     

Passive immunization of pigs against experimental infection with Streptococcus suis serotype 2

The safety and protective efficacy of a horse antiserum raised against inactivated whole cell preparations of Streptococcus suis serotype 2 was investigated in pigs by experimental challenge. The antiserum was evaluated in two similar experiments each comprising 12 4-week-old pigs treated with 6 ml of antiserum the day before challenge and four pigs used as challenge controls. Pigs were infected by subcutaneous injection with approximately 10(11) colony forming units of S. suis serotype 2. Clinical disease in the pigs that could be attributed to infection with S. suis was reduced from 88 to 35% (P = 0.015). The percentage of pigs with lesions that could be associated with S. suis was reduced from 88 to 22% (P = 0.002) and isolation of S. suis serotype 2 was reduced from five (63%) out of eight pigs in the combined challenge control groups to 3 (13%) out of 23 pigs in the combined treatment groups. These results indicate that passive immunization of pigs may be a way to reduce or control S. suis serotype 2 infections in pigs.     

Pathogenicity of Eperythrozoon suis alone and when mixed with Babesia trautmanni in experimentally-infected pigs

The pathogenicity of a single infection with Eperythrozoon suis and of a mixed infection of E. suis and Babesia trautmanni in experimentally-infected pigs, was described. In the pigs with a single infection, parasitaemia of E. suis was observed 4 days after blood inoculation. Although parasitaemia with this parasite was also observed on the 4th day in a mixed infection, the parasitaemia of B. trautmanni was not noted until 14 days after inoculation at a period when that of E. suis had started to fall. No parasitaemia was observed in any of the pigs in the splenectomized and unsplenectomized uninoculated control animals. The pigs carrying either single or mixed infections had pyrexia and their temperatures were consistently higher than those of the control animals. Infected pigs also showed anaemia with significant decline in Pcv, Hb and RBC values. The total WBC count rose in the infected pigs and the rise was more pronounced in pigs carrying E. suis alone. In addition, it was only in pigs infected by E. suis alone that a decline in the percentage of neutrophils and a rise in percentage lymphocytes was observed.     

Respiratory chlamydial infection based on experimental aerosol challenge of pigs with Chlamydia suis

An experimental study of aerogeneous challenge in pigs was conducted in order to reveal characteristic features of porcine respiratory chlamydiosis. Eight conventionally raised pigs were exposed to a pathogenic strain of Chlamydia (C.) suis, four controls were mock infected. Besides pathological changes, the acute-phase and humoral immune responses, as well as the dissemination and transmission of the challenge strain was monitored in the course of infection. The data from clinical investigations, LPS-binding protein assay, antibody ELISAs, confocal laser scanning and light microscopy, immunohistochemical staining and PCR provided extensive evidence of the pathogenic potential of C. suis for the porcine respiratory system. This model appears suitable for further pathophysiological and immunological investigations of chlamydial respiratory infections and can also be recommended for studies of Chlamydia-associated infections of the human lung.     

南疆地区猪链球菌流行病学调查

为了解猪链球菌在新疆南疆地区正常猪群中的流行情况,对库尔勒地区、阿克苏地区、喀什地区无菌采集的286头份健康屠宰猪的扁桃体进行猪链球菌种的鉴定;采用猪链球菌谷氨酸脱氢酶（gdh）基因设计引物,建立PCR方法。结果表明,南疆地区猪链球菌的携带率达到了17．13％;对携带猪链球菌的扁桃体进行细菌的分离鉴定,荻得47株猪源性链球菌;采用多重PCR对分离的47株猪链球菌进行主要致病血清学的检测,未见主要致病血清型。     

猪链球菌感染风险因子分析及控制要点

为控制猪场链球菌感染的风险,降低猪链球菌发病率。我们对猪链球菌感染的可能风险因素进行了分析,引入HACCP理念,绘制了猪场猪链球菌感染的流程图,识别出猪场猪链球菌感染的风险因子及关键控制点(CCP-like),即隐性带菌猪、混群饲养、精液、蓝耳病、伪狂犬及PCV-2型感染等病毒性免疫抑制病、疫苗免疫、药物预防。针对各关键控制点制定出相应的防控措施,为猪链球菌的防控提供了技术思路。     

Porcine coccidia in Papua New Guinea

Faecal samples from 232 domestic pigs raised on concrete, 98 free-ranging village pigs, and five wild boar showed 46.6 (108/232), 54 (53/98) and 80% (4/5) prevalence of coccidian oocysts, respectively. Eight species of Eimeria, and Isospora suis, were recovered. In their descending order of predominance in the pigs raised on concrete, the species of coccidia were E. debliecki (26.7%), E. scabra (22.4%), E. neodebliecki (19.8%), E. porci (15.5%), E. suis (11.6%), E. polita (8.6%), E. perminuta (7%), E. spinosa (5.6%) and I. suis (3.9%). The first five species listed above predominated in the village pigs as well. E. polita, E. spinosa and I. suis were not found in the wild boar. I. suis oocysts prevailed in 8.3% of the 36 sows on concrete, and in 11.1% (3/27) of those which were positive for coccidia. Isosporoid oocysts were absent in the village sows. Of the 125 less than 24-day-old piglets, 29.6% were diarrhoeic, and of these, 43.2% were positive for coccidia. Four of the 16 (25%) coccidia-positive, diarrhoeic piglets, and four of the 37 (10.8%) coccidia-positive non-diarrhoeic piglets shed I. suis oocysts, an observation which seems to weaken the present contention that I. suis is the primary causative agent of neonatal porcine coccidiosis. The highest mean number of oocysts per gram faeces (23,550) was recorded from the diarrhoeic farm piglets on concrete, and the lowest of 6,100 from the gestating farm sows. Mean opg data revealed very little significant quantitative variation between the corresponding age groups of the free-ranging village pigs and the commercially-farmed ones. One of the most interesting findings in the study was that the sows were more frequently infected than all other age groups.     

猪附红细胞体16S rRNA基因的序列测定和系统进化分析

从确诊为猪附红细胞体感染的猪场，无菌采集血样，抽提猪附红细胞体基因组DNA，采用真细菌的通用引物进行16S rRNA基因扩增，对扩增产物进行克隆和测序。从3个地理位置不同的猪场均成功地扩增出长度为1469bp的核苷酸序列。系统进化分析表明，3个猪场样品所测序列一致性达99．52％以上，具有相同的基因型，但与国外报道的猪附红细胞体Illinois株同源性为95％，属于同一基因群，但基因型不同；所有种类的附红细胞体和血巴尔通氏体组成同一进化分支，这类血营养菌与支原体科，支原体属的病原最靠近(75％)，而与立克次氏体目的病原较远(70％)。上述研究证实，广东所流行的猪附红细胞体是一种新基因型的猪附红细胞体，建议命名为猪附红细胞体广东株型；为反映进化关系，猪附红细胞体和其它血营养菌应划归于支原体科的支原体属。     

Eperythrozoon infection in swine: effect on the acid-base balance and the glucose, lactate and pyruvate content of venous blood

The influence of latent and of splenectomy-induced clinically manifest Eperythrozoon suis infection on the following parameters of the carbohydrate metabolism and the acid-base status was tested in venous blood of German Landrace pigs: Levels of glucose, lactic and pyruvic acid, blood-pH, base excess, actual bicarbonate concentration, standard bicarbonate concentration, pCO2, pO2. The latent E. suis infection resulted in a consistent decrease of blood glucose level. 23 days after infection, blood glucose was reduced by 25% of the initial value. The other parameters were not changed by latent E. suis infection. Acute Eperythrozoonosis induced severe hypoglycaemia (means Gluc, = 39.7 mg/dl and blood acidosis (means pH = 7.13). In vitro experiments showed that break-down of glucose in E. suis infected blood occurs very rapidly. There was no significant reduction of the glucose concentration in control blood that had been treated accordingly. There was an increase of lactic acid (means = 62.7 mg/dl), pyruvic acid (means = 1.86 mg/dl), and pCO2 (means = 82.1 mm Hg). The concentrations of actual bicarbonate (means = 24.8 mmol/l) and standard bicarbonate (means = 20.9 mmol/l) were lowered, and there was a negative base excess (means = -3.56 mmol/l). The ratio of lactic and pyruvic acid changed from 11:1 to 30:1. It seems likely that E. suis itself is able to metabolize glucose. Acidosis is considered to result from both the increase of lactic acid (metabolic component) and an impairment of pulmonary gas exchange (respiratory component).     

Indirect hemagglutination for Eperythrozoon suis detection in experimentally and spontaneously infected swine

Ten splenectomized and non-splenectomized pigs were experimentally infected with E. suis bearing red blood cells in order to determine the antibody response. All animals were monitored for antibody titer by indirect hemagglutination over a period of 80-290 days postinfection. Latent E. suis infection only yielded a detectable antibody titer in one pig. Acutely infected pigs had a titer ranging up to 1:640. Maximum antibody response lasted only 2 months and dropped below the level of detection of our assay within 2 to 3 months. At this time, the clinical symptoms could reappear and antibodies were again detectable. However, no booster effect was observed with this second outbreak. We also determined the antibody frequency in 138 pigs from 16 herds in Southern Germany. Pigs from only 4 out of 6 clinically positive herds had antibody titer against E. suis. 20 out of 78 pigs of the clinical positive herds demonstrated a detectable E. suis antibody titer. In 10 herds that were asymptomatic and presumed uninfected all 80 pigs were serologically negative for E. suis.