猪链球菌病的诊断和防治

1　临床症状及剖检变化某猪场存栏猪 5 0 0 0余头 ,于 1 999年 1 0月发生该病 ,从保育猪舍开始 ,2～ 3天发病蔓延到整个猪场 ,先后发病 82 0头 ,经紧急治疗仍死亡 3 2 5头 ,病死率为 3 9.6 %。表现突然发病不食 ,体温 41～43℃ ,结膜潮红、流泪。有浆液性鼻液 ,呼吸困难 ,腹下、四肢、耳尖等处皮肤呈出血性紫斑 ,少部分育成病猪表现明显的神经症状 ,共济失调 ,倒地四肢做游泳状 ,磨牙或口吐白沫 ,大多于 1～ 3天内死亡 ,症状较轻及治愈者 ,偶留有跛行或生长不良。剖检变化差异较大 ,主要为全身淋巴结充血肿胀 ,脾脏肿大 1～ 3倍 ,边缘发生出…     

Efficacy of tiamulin against experimentally induced Streptococcus suis type-2 infection in swine

Eighteen 4-week-old pigs were used in a study to evaluate tiamulin in drinking water for control of experimentally induced Streptococcus suis type-2 infection. Pigs in groups A and B (n = 6 pigs/group) were aerosolized with a logarithmic-growth phase culture of S suis type 2, whereas pigs in group C (n = 6 pigs) served as noninfected and nonmedicated controls. After exposure to S suis, pigs in group B were given 180 mg of tiamulin/L of drinking water for 5 days. Pigs in group B consumed more feed (P = 0.009) and gained body weight faster (P = 0.02) than did pigs in group A. Pigs in group A had higher rectal temperature (P = 0.05) for up to 7 days after S suis exposure, higher clinical sign scores (P = 0.008), higher serum cortisol concentration on days 7 and 14, higher gross lesion scores (P = 0.03), and higher microscopic lesion scores (P = 0.01) than did pigs in groups B and C. Gross and microscopic lesions in pigs of groups A and B included meningitis, pneumonia, pleuritis, pericarditis, peritonitis, and synovitis of variable severity. Streptococcus suis type 2 was recovered from tissue specimens of 2 group-A pigs and 1 group-B pig. Data indicated that tiamulin administered via drinking water significantly reduced the effects of S suis type-2 infection.     

Isolation of Streptococcus suis from swine in Nebraska

Streptococcus suis was isolated from swine with localized and diffuse infections. The isolates (n = 121) were unable to grow in broth containing 6.5% NaCl. Their abilities to hydrolyze esculin were variable, as were their fermentative reactions in lactose, trehalose, raffinose, and inulin. Sorbitol was not attacked by any strain. Serologic reactions were obtained between the isolates and coagglutination reagents prepared from commercially available antisera to streptococcal groups D, R, or S.     

Plasma haptoglobin concentration in swine after challenge with Streptococcus suis

Eight 15-week-old pigs, reared under specific pathogen-free conditions, were inoculated with Streptococcus suis serotype 2. The animals were monitored before and after challenge by measuring rectal temperature, recording specific clinical symptoms and collecting blood samples for haptoglobin determination. Twenty-four hours after infection, the average haptoglobin plasma concentration of the animal group increased significantly and reached a maximum 4 days post-inoculation, followed by a constant mean level until the end of the trial on day 10. In spite of individual differences between the animals, an increase in haptoglobin concentration of at least 2.5 times above normal was observed in all infected pigs 1 day after challenge. Twenty-four hours after challenge, lameness was observed in five animals and an elevated body temperature was observed in seven of the eight experimental infected animals. These are the classical clinical symptoms of streptococcal infection. Haptoglobin was shown to increase in acute S. suis infection in pigs.     

Epidemiological relationship of human and swine Streptococcus suis isolates

Two cases of meningitis due to Streptococcus suis in humans are reported here. A butcher and an abattoir worker were referred to a health centre in Castellón (Spain) with fever and symptoms of meningitis. After adequate treatment, a slight hipoacusia persisted as sequelae in both cases. Colonies of S. suis group R, serotype 2 and phenotype MRP+EF+ were isolated from cerebroespinal fluid. Epidemiological studies showed that both workers had in common the handling of pork meat of slaughtered healthy pigs from three closed farms. A study of the tonsils from apparently healthy, slaughtered pigs was carried out. A total of 234 tonsillar samples were obtained and 81 strains of S. suis were isolated from them. Serotype 2 appeared to be the most frequent (50.6%), and the analysis for phenotype showed a high percentage of tonsillar strains with the phenotype MRP+EF+ (35.9%). The humans and 28 tonsillar swine strains showed a similar profile (S. suis group R, serotype 2 and phenotype MRP+EF+). A total of 26 of the swine isolates were analysed by ribotyping using EcoRI. The human strains showed the same six-band hybridization pattern that shared five bands with the pattern most frequently shown by most of the tonsillar N. suis group R, serotype 2 and phenotype MRP+EF+ strains, differing only in the lightest, faintest band which was slightly less anodical in human (> or = 1.8 kb) than in swine (approximately 1.8 kb). From these results, both groups of strains, humans and porcine, showed differences; how can these differences in the pattern of ribotyping be explained if they should have the same origin? Is it possible that they have undergone an adaptation to the new host or perhaps the modification is due to other unknown causes? Further studies in this area are required in order to answer these questions.     

Studies of Streptococcus suis type 2 infection in pigs

Investigations into the immunology, pathogenesis and epidemiology of Streptococcus suis type 2 infections were carried out in experimental pigs and in naturally-occurring field outbreaks of disease. The capsular polysaccharide from Str. suis type 2 was shown to induce opsonic antibodies in pigs when injected with Freund's incomplete adjuvant, but difficulties encountered in experimental production of the disease prevented a study of their protective effects. Problems with the bactericidal tests led to an investigation of other assays for antibodies against Str. suis type 2, namely, a phagocytic test with pig neutrophils, a mixed reverse passive antiglobulin haemagglutination test and an indirect haemagglutination test. There was evidence that with modifications both the latter tests would be useful. Transmission studies in 39 conventionally-reared and 7 hysterectomy-derived, colostrum-deprived pigs yielded interesting results with regard to the distribution of the organism in relation to the disease process. Tonsil carriage in clinically-healthy pigs was demonstrated after experimental and natural infection. Detectable carrier rates varied between 0 and 59%. The organism was shown to persist in the presence of circulating opsonic antibodies and in pigs on penicillin-medicated feed. Attempts to isolate the organism from the genital tract were unsuccessful. Medicated early weaning and classical SPF techniques applied to infected herds appeared to be effective in producing pigs free from Str. suis type 2 infection.     

Antimicrobial susceptibility of Streptococcus suis isolated from clinically healthy swine in Brazil

Streptococcus suis is an important pathogen in the swine industry. This study is the first to report on the antimicrobial susceptibility of S. suis isolated from clinically healthy pigs in Brazil; the fourth major pork producer in the world. The antimicrobial susceptibility of 260 strains was determined by disc diffusion method. Strains were commonly susceptible to ceftiofur, cephalexin, chloramphenicol, and florfenicol, with more than 80% of the strains being susceptible to these antimicrobials. A high frequency of resistance to some of the antimicrobial agents was demonstrated, with resistance being most common to sulfa-trimethoprim (100%), tetracycline (97.69%), clindamycin (84.61%), norfloxacin (76.92%), and ciprofloxacin (61.15%). A high percentage of multidrug resistant strains (99.61%) were also found. The results of this study indicate that ceftiofur, cephalexin, and florfenicol are the antimicrobials of choice for empirical control of the infections caused by S. suis.     

Brucella suis biovar 3 infection in a Kentucky swine herd

Sows from a large farrow-to-finish operation in western Kentucky had late-term abortions. Boars and breeding-age sows were tested serologically for brucellosis, and 83 of 125 were classified as reactors. No brucellae were isolated from the tissues of 6 unbred reactor sows, but Brucella suis biovar 3 was recovered from 5 aborted fetuses. Epidemiological studies failed to determine the source of the infection.     

Agents of the "suis-ide diseases" of swine: Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis.

In recent years, Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis have emerged as important pathogens of swine, particularly in high health status herds. Their association with a wide range of serious clinical conditions and has given rise to the moniker "suis-ide diseases." These organisms are early colonizers and, for that reason, are difficult to control by management procedures such as segregated early weaning. Vaccination, serodiagnostic testing, and even serotyping are complicated by the presence of multiple serotypes, cross-reactive antigens, and the absence of clear markers for virulence. In this review, we discuss our current understanding of the pathogenesis, epidemiology, and management of the causative agents of the "suis-ide diseases" of swine.     

猪败血性链球菌与附红细胞体混合感染病例

猪败血性链球菌病是猪链球菌感染引起的一种急性败血性传染病,猪附红细胞体病是由猪附红细胞体寄生于猪红细胞而引起的一种散在的热性、溶血性传染病.本文以某猪场这2种病混合感染病例为题材,从发病基本情况、临床症状、剖检变化、实验室检验、防治措施等6个方面对该混合感染病例做了详尽的阐述.     

An indirect hemagglutination test for the diagnosis of Eperythrozoon suis infection in swine.

An indirect hemagglutination test was developed to detect naturally occurring eperythrozoonosis in swine and to follow experimentally induced infections serologically. The antigen used was prepared from the plasma of acutely infected, splenectomized pigs. The test was specific and reliable in detecting swine latently infected with the disease.     

猪链球菌病研究进展

猪链球菌(Streptococcus suis)是一种重要的人兽共患病病原体,能够引起猪的疫病,人类感染该菌可导致脑膜炎、败血症,甚至死亡.该菌对养猪业造成严重经济影响,对公共卫生事业构成巨大威胁.由于猪链球菌血清型较多,抗原结构复杂,在临床上又可呈现不同的症状,如败血症、脑膜脑炎、心内膜炎、肺炎、化脓性淋巴结炎、关节炎等,还常常与其他疾病发生合并感染.近几年来,该病的发病率和死亡率有逐年上升趋势.链球菌的致病性已引起临床工作者和科研人员的广泛关注和重视,国内外许多学者对猪链球菌做了大量的研究工作,已发现的猪链球菌2型的致病因子包括荚膜多糖、溶菌酶释放蛋白、细胞外因子、蛋白质片段和IgG结合蛋白、溶血素等.     

Isospora suis infection in piglets. A review

Recently several reports have been published on the association of Isospora suis with diarrhea in piglets. A review is given of. suis infection in piglets, in which the taxonomy, life cycle, pathogenicity, immunity, and treatment of I. suis and related organisms are discussed.     

附红细胞体自然感染猪血液流变学

选择临床健康的2月龄附红细胞体自然感染仔猪15头,每周采血1次,连续4次,检测血样的RBC、PCV、ηb10s-1、ηb150 s-1、ηp、ηre10 s、ηre150 s-1、AI、RI、TK.检测结果如下随着猪附红细胞体感染强度的增强,ηb10 s-1、ηre10s-1、ηre150 s-1、AI、RI、TK明显增高,而RBC、PCV、ηb150 s-1、ηp无明显变化,表明猪感染附红细胞体后,血液粘度增高,红细胞聚集性增高,红细胞变形能力降低,进而影响脏器组织的血液灌注和微循环功能.这些血液流变学改变,构成了血栓、炎症、变性、水肿、坏死等的病理学基础.