Immunological Activity of Leptospira Pomona Bacterins

Seven commercially available leptospiral bacterins were compared in guinea pigs and on that basis two of them, the best and the poorest, were further compared in calves. A wide variation was observed in their antigenicity and in their ability to provide protection. Guinea pigs appeared to be satisfactory test animals for evaluation of bacterins prepared for use in cattle.     

Pathological and Bacteriological Studies of Hydrosalpinx in Buffaloes

The objectives of the present study were to investigate the bacteria accompanying hydrosalpinx of the buffalo cow and investigate the correlation between bacterial infection of the uterus and hydrosalpinx. Buffalo cows’ reproductive tracts were collected from Mosul abattoir. A total 385 uterine samples were examined of which 25 were having hydrosalpinx. Swabs for bacteriology, fluid for cytology and biopsies for histopathology were collected from the hydrosalpinx and the uterus from each samples included in this study. Results of this study indicated high prevalence of hydrosalpinx (6.5%) including unilateral (n = 19; 76%) and bilateral (n = 6; 24%) hydrosalpinx. Although 16 samples (64%) of the hydrosalpinx samples had no bacterial growth, the most prevalent bacteria recovered from hydrosalpinx were Corynebacterium hemolyticum and Actinomyces bovis, 42.8% and 28.6%, respectively. The most prevalent bacteria in the uterus were Archanobacterium pyogenes (18.5%), Staphylococcus aureus (14.8%), and Listeria monocytogenes (11.0%). Higher rates of leukocytes infiltration (p < 0.01) were observed in the uterine discharge than hydrosalpinx. A significant (p < 0.01) increase in lymphocytes was found in uterine discharge. Microscopic examination of the hydrosalpinx showed mucosal atrophy and dilatation of oviductal lumen without any signs of inflammation. It could be concluded that there is no correlation between bacteria isolated from uterus and hydrosalpinx. No association was found between bacteriological cultures and hydrosalpinx. Inflammation of the uterine tissue could be extended to utero‐tubal junction producing local inflammation resulting in fibrosis and tubal obstruction. The obstruction in the lumen of the oviducts resulted in accumulation of fluid.     

急性非洲猪瘟的实验病理学研究

旨在通过对非洲猪瘟临床病理学和组织病理学的研究,探讨病理学变化与疾病发生发展的内在关系及其病理机制。选用体重20 kg左右的长白猪13头,肌内注射非洲猪瘟病毒毒株Pig/HLJ/18,剂量10²HAD₅₀·mL^-1。试验期间的死亡猪,全部进行系统剖检和取材,制备石蜡切片,苏木素伊红染色。建立病理学评价标准,病变（无序分类变量）用频率和百分比表示,病变程度（有序分类变量）按各组织器官的不同病变进行分级和评分。结果表明,发病猪符合非洲猪瘟急性、热性、高传染性等临床特征,发病率100%,病死率100%。病死猪表现败血症典型特征,尸体易腐败,血凝不良或溶血,尸僵不全。主要病理损伤为出血性坏死性淋巴结炎、急性炎性脾肿（败血脾）、脑水肿、肺水肿和肺实变等。脾和淋巴结是非洲猪瘟病毒攻击的靶器官,病变最为显著,出现时间最早,持续时间最长,发生频率最高。病理变化以血液循环障碍尤为突出,包括水肿、充血、淤血、出血、梗死和弥散性血管内凝血等多种病理表现,出血性病变为其最主要的特征。非洲猪瘟病毒引发的以淋巴细胞渗出为主的炎症反应贯穿始终,在病程的中后期表现更为明显。结果提示,急性非洲猪瘟的主要病理过程为典型的免疫/炎症级联反应和严重的全身血液循环障碍,共同导致急性非洲猪瘟的高发病率和高死亡率。     

Experimental Pathological Study of Acute African Swine Fever

To study the clinicopathology and histopathology of African swine fever (ASF), and to explore the internal relationship between pathological changes and disease occurrence and development and its pathological mechanism, 13 Landrace pigs with bodyweight about 20 kg were intramuscular injected with African swine fever virus (ASFV), strain Pig/HLJ/18 at a dose of 10²HAD₅₀·mL^-1. During the experiment, all the dead pigs were systematically dissected and sampled, paraffin sections were produced, and haematoxylin-eosin staining was performed. Clinicopathological evaluation standards for acute ASF were established, then pathological lesions (classification variables) were expressed by counting frequency and percentage, and the lesion degree (continuous variables) was graded and scored according to different pathological changes of various tissues and organs. The results showed that all infected pigs were in line with the clinical characteristics of ASF, including acute, febrile and highly infectious, with a 100% incidence rate and 100% mortality. The dead pigs showed typical characteristics of septicemia, cadavers prone to corruption, blood clotting adverse or hemolysis, rigor mortis incomplete. The main pathological lesions were hemorrhagic necrotizing lymphadenitis, acute inflammatory splenomegaly (septic spleen), cerebral edema, pulmonary edema and lung consolidation et al. The spleen and lymphonodus are the target organs attacked by ASFV, with the most significant lesions, the earliest occurrence time, the longest duration and the highest frequency. The most prominent pathological changes are blood circulation disorders, including multiple pathological manifestations such as edema, hyperemia, congestion, hemorrhage, infarction, disseminated intravascular coagulation (DIC), and the most important characteristics are hemorrhagic lesions. The inflammatory reaction of lymphocytic exudation caused by ASFV runs through the whole process, especially in the middle and later stages of the course. The results suggest that the main pathological process of acute African swine fever is a typical immune/inflammatory cascade reaction and severe systemic blood circulation disorder, which resulted in the high incidence rate and high mortality rate of acute ASF.     

An isolation of Leptospira serotype Pomona from a domestic cat

Extract

Between November 1971 and July 1972, the gastro-intestinal tracts of 51 dogs and 47 cats of various age were examined for helminth parasites. The animals examined were unselected and had been submitted for autopsy following death from causes unrelated to parasitism. Most of the animals were pets, but included in the survey were some working dogs. All came either from the city of Palmerston North or its surrounding rural areas.     

Clinical and Pathological Observations on the Experimental Passage of Swine Dysentery

The length of incubation for 36 eight and 12 week old swine in eight experimental passages averaged 11 days and ranged from five to 24 days. The duration of diarrhea for 24 of these swine averaged 6.4 days and ranged from two to 19 days. The consistent macroscopic lesion was a colitis and, subsequently, a typhlitis. In the swine euthanized on the first day of diarrhea, the colitis was most intense in the coils near the apex of the colon and, frequently, these swine had a hyperemia of the fundus of the stomach. The amount of visible blood in the colon varied. Organisms identified microscopically and ultrastructurally as spirochetes were observed commonly in the feces and the mucosal glands of the colon of swine with a diarrhea, but not in the adjacent mesenteric lymph nodes. These spirochetes which were the most numerous on the first day of diarrhea, could not be isolated and propagated in vitro. Swine which recovered naturally or were medicated at the height of a diarrhea, developed a resistance to swine dysentery. Colon from infected swine remained infectious when stored at -77°C for nine months but not when stored at -16°C. Feces from infected swine were not infectious after lyophilization and storage at -12°C.     

Influence of Diet on Experimental Swine Dysentery. 3. Pathological Changes

Three experiments have been carried out to elucidate the possible influence of the vitamin E and selenium content of the feed on experimental swine dysentery. In most of the pigs given a vitamin E and selenium deficient diet, large and diffuse pseudomembranes appeared in the spiral colon, which also usually displayed a distended appearance and prominent oedematous infiltrations in the mesentery. The histological examination revealed large fibrinous pseudomembranes attached to defects on the mucosal surface. There were also pseudo-membranes containing necrotic mucosal tissue. Fibrinoid thrombi within minute vessels were readily observed in the latter lesions. The vitamin E supplemented pigs had colonic lesions very much like the deficient animals, while half of the selenium supplemented animals developed none or moderate inflammatory changes, the other half displayed, however, prominent pseudomeinbranes in the colon. Ten out of 26 pigs supplemented with both vitamin E and selenium were not affected by swine dysentery. In the remaining pigs catarrhal inflammatory lesions dominated in the colonic mucosa. In some of these animals pseudomembranes occurred, but they were usually small and of limited distribution. The vascular thromboses and tissue necrosis demonstrated within the colonic lesions are found to be compatible with a Shwartzman reaction. Erythrocytic “thrombi” and other phenomena associated with stasis are further believed to be of pathogenetic importance in this respect. It is emphasized that this report also illustrates the enhancing effect of a combined supplement of vitamin E and selenium on resistance to swine dysentery.     

A unique genotype of Leptospira interrogans serovar Pomona type kennewicki is associated with equine abortion

Although serologic data indicate horses in N. America are exposed to a variety of leptospiral serovars, abortion is almost always associated with Leptospira interrogans serovar Pomona type kennewicki. A variety of wildlife including raccoons, white tailed deer, striped skunks, opossums, and red and grey foxes have been shown to host serovar Pomona and have therefore been suspect as sources of infection for pregnant mares. The aim of the present study was to examine genetic diversity in serovar Pomona type kennewicki in wildlife and in aborting mares. Our approach utilized PCR that targeted tandem repeats at the VNTR - 4 locus and a 1235 bp 5'-sequence of the lk73.5 (sph2) and adjacent upstream sequence unique to serovar Pomona. All isolates/specimens of equine origin in 1992 and 2008 yielded amplicons of 1235 and 595 bp, whereas 14 isolates/specimens from wildlife yielding a 1235 bp amplicon characteristic of serovar Pomona produced amplicons of 1300, 550 bp (3), 1300 bp (10), or 595 bp (6) with the VNTR - 4 primer set. Wildlife therefore hosted at least three different genetic variants of type kennewicki including the genetic variant that predominated in aborting mares. The data are consistent with other studies indicating specific genetic variants of type kennewicki show a strong tendency to be associated with a specific host. Levels of antibody in wildlife sera reactive with rLk73.5, rLig130 and sonicate of type kennewicki were poorly correlated with PCR data, although rLk73.5 was superior to rLig130 in detection of antibody responses. PCR is therefore a more reliable tool for studies of wildlife reservoirs of Leptospira sp. than serologic surveillance that targets host induced proteins or LPS-rich sonicate.     

Porcine Hemophilus parahemolyticus Pneumonia in Saskatchewan II. Bacteriological and Experimental Studies

The incidence of porcine pleuropneumonia caused by Hemophilus parahemolyticus has shown a marked increase in recent years in some countries. Isolation of a strain distinct from European serotypes was made from a natural outbreak of the disease in pigs in Saskatchewan. Experimentally infected pigs did not develop clinical signs but pathologic-anatomic studies of lungs revealed the presence of necrotizing fibrinous pneumonia with intense proliferation of mesenchymal tissue elements. Similar extensive fibroblastic activity had been found to be a typical feature in the natural infection. It is speculated that the Saskatchewan strain may have invasive patterns different from European serotypes.     

实验性鸡病毒性关节炎病理学研究

应用国内分离的鸡病毒性关节炎病毒“吉毒株”(VAV—J)成功地复制了鸡病毒性关节炎(VA).详细观察了实验性鸡病毒性关节炎的临床症状,并运用肉眼、光镜、电镜及免疫琼脂扩散等技术对该病进行了系统的病理学研究.结果表明,实验性鸡病毒性关节炎腱断裂病变少见;急性期,关节与腱鞘滑膜下网状细胞增殖,大量异染性细胞、淋巴细胞和巨噬细胞浸润,有的严重出血;慢性期,滑膜形成绒毛样突起,并有淋巴细胞性结节形成,并见籽骨骨化障碍;未发现以异染性细胞浸润为主的心肌炎;免疫器官具有明显病变.关节液中病毒粒子的检出率为100%,可用于本病的诊断.     

实验性猪口蹄疫免疫病理形态学研究

选用健康仔猪13头,分成4组:健康对照组2头,健康攻毒组5头,免疫组和免疫攻毒级各3头。健康攻毒组经皮下注射猪口蹄疫病毒(FMDV);免疫组和免疫攻毒组均经皮下接种猪口蹄疫牛皮肤细胞弱毒苗(FMD-BC),观察1个月后,前者扑杀,后者再攻FMDV,1个月后扑杀。结果:健康攻毒组5头仔猪均出现口蹄疫(FMD)典型的临床症状和病现学变化,其淋巴结、脾脏不同程度的变性、坏死和出血,淋巴小结减少和缩小,淋巴细胞稀少,浆细胞呈坏死性变化,酯酶阳性(ANAE~ )细胞和次级淋巴小结均减少;免疫组未见任何FMD病理学变化,主要见全身各部位淋巴结及脾脏不同程度地增大,尤以肩前、髂下和脾门淋巴结更为显著,其淋巴小结显著增多、增大,淋巴细胞活化,大、中淋巴细胞增多,以过渡型和未成熟型浆细胞为主,ANAE~ 细胞和次级淋巴小结均增多;免疫攻毒组的变化与免疫组相似。     

疑似猪瘟病例的病理学诊断

对送检的42例疑似猪瘟或伪狂犬病病例样品进行了病理学诊断。样品主要包括扁桃体、淋巴结、脾脏、肺脏、肾脏、肠、脑等,通过甲醛固定,石蜡切片,H.E.染色后进行显微镜下观察,结果显示,主要的病理变化包括扁桃体炎、脾炎、淋巴结炎、肠炎、肺炎、肾小球分叶增多、脑膜脑炎,未见伪狂犬病嗜酸性包涵体。结合相关病理学知识,初步判定疑似猪瘟。     

非典型猪瘟的病理学检查及诊断

猪瘟是由猪瘟病毒所引起的传染性强、病死率高的烈性传染病，在世界上许多养猪国家均有不同程度的流行［１］，是国际兽疫局规定必需检疫的Ａ类传染病，为此各国都致力于消灭猪瘟的工作。我国５０年代后由于兽医科技人员的一致努力，通过广泛的免疫接种，基本上控制了本病的发生与流行。但８０年代以来我国的猪瘟疫情又有重新抬头趋势，随着普遍的猪瘟疫苗的免疫接种，猪体内存在不同程度的免疫抗体。近两年猪瘟的发病形式和特征都有所变化，急性病程及较大规模的暴发流行已较少发现，而代之以病程较长、症状病变轻微不显著的所谓“非典型猪…     

Studies on the Susceptibility of Water Buffaloes to Leptospira

Eight mature farming type, Taiwan, water buffaloes were inoculate with L. australis A while six received L. canicola. Before inoculation all animals were negative to the microscopic-agglutination test (agglutinationlysis test) using the above species as antigen.

No sign of clinical leptospirosis was observed although four animals developed temperatures.

Cultures made from buffalo blood, kidneys and urine and from blood of guinea pigs inoculated with kidney emulsion and urine from the inoculated buffalo were all negative for leptospiral organisms.

Blood samples drawn from the water buffalo 2, 3 and 4 weeks post inoculation were negative to the microscopic-agglutination test except for one animal. Blood from the animal taken two weeks post-inoculation was positive at 1:100 dilution with L. australis A antigen but that taken at 3 and 4 weeks was negative.

     

天然富硒牛奶的实验研究

１６头泌乳期相近的健康荷斯坦奶牛，随机分为４组，Ⅰ组不予处理作为对照，Ⅱ、Ⅲ、Ⅳ组每天分别按低、中、高（０．５×１０－６，１．０×１０－６，１．５×１０－６）３个剂量水平于精料中添加亚硒酸钠。实验前及投硒后每隔２０ｄ采集血液、乳汁和毛样１次，检测各项指标。实验观察期８０ｄ。结果表明，奶牛日粮中添加不同水平的无机硒盐，能显著提高试验牛血清、乳汁和被毛中的硒含量，其升高幅度与投硒量成正相关；Ⅳ组牛的奶硒含量达到稳定高台期约需６０ｄ，其平均值为０．０９０ｍｇ／Ｌ，比对照组提高约４倍；而奶中乳糖、乳脂、乳蛋白等成分以及钙、磷、铜、锌、铁等矿物元素无明显变化（Ｐ＞０．０５）。在整个实验观察期，试验牛红细胞数、血红蛋白量等血常规指标，血清钙、磷、锌等矿物元素含量，以及ＧＯＴ、ＣＰＫ、ＡＬＰ、ＵＮ等１０余项肝、心、肾功能指标均无显著性改变（Ｐ＞０．０５），临床表现及产奶量亦无明显变化；血清硒、毛硒含量远低于中毒标准的下限，表明本添加剂连续投服８０ｄ对奶牛无毒副作用。Ⅲ、Ⅳ组牛的淋巴细胞转化率、淋巴细胞数以及γ球蛋白含量增加，表明奶牛免疫机能有所增强。