Prevalence of Haemophilus parasuis serovars isolated in Spain from 1993 to 1997

From 1993 to 1997, 327 strains of Haemophilus parasuis were isolated from spanish swine in our Diagnostic Laboratory and 174 strains (53.2%) were serotyped. Four serotypes, sv. 5 (18.4%), sv 4 (16%), sv. 2 (9.2%) and sv. 13 (8%) were the most frequently isolated and 29.3% of the studied strains were classified as non typable. The results obtained indicate that the distribution of the serotypes in Spain is very similar to that found by other researchers in Germany, Australia, Canada and alike to that found in the United States.     

广西地区副猪嗜血杆菌ERIC-PCR指纹图谱分型研究

为探讨肠道细菌基因间重复序列(ERIC)的聚合酶链反应(PCR)技术用于副猪嗜血杆菌基因分型的可行性,对分离自广西地区不同猪场的22株副猪嗜血杆菌进行ERIC-PCR指纹图谱分型研究.结果发现,22株分离株显示出12种指纹图谱,可以区分无法进行血清分型的菌株.表明ERIC-PCR可适用于对副猪嗜血杆菌进行分子流行病学调...     

Experimental colonization of piglets and gilts with systemic strains of Haemophilus parasuis and Streptococcus suis to prevent disease.

Haemophilus parasuis and Streptococcus suis are both major causes of losses during the nursery period, especially in herds using the segregated early weaning system. In this system, only a few piglets may be colonized with the herd's prevalent systemic strain, which results in infection of naive penmates late in the nursery. In view of these factors, the objectives of this study were: (1) to evaluate the early colonization of piglets with the farm's prevalent systemic strain of H. parasuis and S. suis as an alternative method for disease prevention; and (2) to evaluate 2 different protocols for experimental colonization: direct colonization of piglets and colonization of piglets through nose-to-nose contact with inoculated sows. Haemophilus parasuis and S. suis isolates recovered from diseased nursery pigs were characterized by the rep-PCR technique and the herd's prevalent strains were used for colonization. Piglets in the experimentally colonized groups were inoculated at 5 days of age by the oral route using a spray pump. Sows were colonized at 2 weeks prior to farrowing using a similar protocol. Although both colonization protocols were successful in getting the piglets colonized, direct inoculation of 5-day-old piglets with the herd's systemic strains of H. parasuis and S. suis tended to be more effective in reducing the morbidity and the mortality than the colonization of piglets by nose-to-nose contact with inoculated sows.     

Protection of vaccinated pigs against experimental infections with homologous and heterologous Haemophilus parasuis

The efficacy of a new Haemophilus parasuis vaccine for pigs was investigated. The vaccine contains H parasuis serotype 5 cells and is adjuvanted with Diluvac Forte (Intervet). Groups of pigs were vaccinated at five and seven weeks with 2 ml and their littermates served as unvaccinated controls. The vaccinated pigs were protected against a challenge with another strain of Hparasuis serotype 5 at two, eight and 17 weeks after the second vaccination, whereas the controls became very ill. The susceptibility of the pigs to the infection decreased with increasing age. After a heterologous challenge with H parasuis serotypes 1, 12, 13 and 14, two weeks after the second vaccination, the vaccine also gave clear protection. The severity of the illness among the control pigs differed with the different serotypes.     

aroA gene PCR-RFLP diversity patterns in Haemophilus parasuis and Actinobacillus species

The Haemophilus parasuis aroA gene encodes 5-enolpyruvylshikimate-3-phosphate synthase and participates in the aromatic amino acids and the folic acid universal metabolic pathway of bacteria. The application of aroA-based PCR-RFLP methodology yields a significant degree of diversity in H. parasuis and Actinobacillus species. PCR amplification of the aroA gene rendered a 1,067-bp fragment in all 15 H. parasuis serovars, and also in Actinobacillus pleuropneumoniae serotypes 1-12, Actinobacillus lignieresii, Actinobacillus equuli, Actinobacillus porcinus, Actinobacillus rossii, Actinobacillus suis, Actinobacillus ureae, Actinobacillus minor and Actinobacillus indolicus. Sau3AI and RsaI digestions of the aroA PCR products rendered seven different restriction fragment length polymorphism (RFLP) patterns: group I (H. parasuis serovars 1, 2, 4-6, and 8-15, A. porcinus and A. ureae), group II (H. parasuis serovars 3 and 7, and A. pleuropneumoniae serotypes 1, 4, 5, 9, 11 and 12), group III (A. lignieresii), group IV (A. pleuropneumoniae serotype 7), group V (A. pleuropneumoniae serotypes 2, 3, 6 and 8, A. equuli, A. rossii, A. minor and A. indolicus), group VI (A. suis) and group VII (A. pleuropneumoniae serotype 10). This is the first report describing the presence of aroA gene in H. parasuis, A. lignieresii, A. porcinus, A. rossii, A. suis, A. ureae, A. minor and A. indolicus and the data presented here demonstrates a significant degree of aroA genetic diversity in H. parasuis and species of the genus Actinobacillus.     

副猪嗜血杆菌的分离鉴定及相关特性研究

本试验从2013年北京地区疑似副猪嗜血杆菌病病料中分离到19株革兰氏阴性短小杆菌,对分离株进行培养特性、荚膜染色、生化特性、血清型分型及PCR鉴定,结果显示分离的19株细菌均为副猪嗜血杆菌（Haemophilus parasuis,Hps）,分别属于血清4、5、7、12及13型。对分离株进行药敏试验及致病性试验,结果表明各分离株均有多重耐药性,且各分离株除GS-3外均有较强毒力。     

副猪嗜血杆菌病研究进展

近年来,由副猪嗜血杆菌(Haemophilus parasuis,Hps)所引起的猪群多发性浆膜炎和关节炎在中国各地屡有发生,对仔猪和青年猪造成严重危害,给养猪业带来了巨大的经济损失,目前,该病已成为全球范围内影响养猪业的典型细菌性疾病。副猪嗜血杆菌血清型复杂,分离培养困难。为了全面认识该病,对其病原学、病理变化、流行病学、致病因子、诊断方法、免疫防治等进行了综述。     

副猪嗜血杆菌病的诊断及防治

2015年3月,江苏省泰兴市某猪场仔猪发生疑似副猪嗜血杆菌病。经过一系列综合诊断,初步诊断为副猪嗜血杆菌病。经药敏试验选择高敏药物进行治疗,最终控制和扑灭该病。主要介绍了该起病例的诊治经过,并与猪链球菌病的病理变化进行了鉴别,以期为兽医同仁提供参考。     

副猪嗜血杆菌流行病学调查及两株分离株耐药性和致病性分析

为了解山东地区副猪嗜血杆菌病的流行情况和流行菌株的生物学特性及致病性,将2016-2018年山东省12个地区送检的103个发病猪的病料进行细菌分离,并对疑似菌株进行形态学观察、PCR鉴定及血清型鉴定,对两株流行菌株进行了培养特性观察、生化特性鉴定、药敏试验及致病性研究。最终分离获得29株副猪嗜血杆菌,分离率为28.16%,其中血清型4型和5型最为流行,其次是1型和12型。该病多发于春秋两季,31~50日龄的仔猪感染率最高。两株流行菌株LZ株和LC株均对青霉素类、头孢类等药物高度敏感,LZ株对庆大霉素、卡那霉素等中度敏感,对林可霉素、链霉素不敏感,LC株对庆大霉素、林可霉素等中度敏感,对卡那霉素、链霉素不敏感;生化特性试验结果显示,LC株和LZ株的硝酸盐还原试验、接触酶试验、葡萄糖发酵试验以及果糖发酵试验的结果均为阳性,吲哚试验、氧化酶试验、甘露醇发酵试验的结果均为阴性;动物致病性试验表明LZ株和LC株均具有较强的毒力,最小发病剂量分别为4.5×10^9 CFU和6.0×10^9 CFU。该研究为副猪嗜血杆菌病的防治提供了重要的参考依据。     

The effect of season and vaccination for Glässer's disease and post-weaning Colibacillosis in an outdoor pig unit endemically infected with virulent strain of Haemophilus Parasuis serotype 5 and pathogenic Escherichia coli

The objective of this field trial was to determine if vaccination against Haemophilus parasuis serovar 5 (HPS 5) and pathogenic serotypes of Escherichia coli would improve nursery pig performance in an outdoor unit in different seasons. The unit was concurrently infected with HPS 5 and with different serotypes of E. coli. All piglets were born to HPS 5 vaccinated sows. The trial was carried out in four (two summer and two winter) groups. Group 1 (E. coli and HPS vaccinated, summer season) (n = 362): Piglets were vaccinated pre-weaning with inactivated E. coli-VT2e-toxin and post-weaning against HPS 5. Group 2 (non-vaccinated, summer season) (n = 349): Piglets were not vaccinated. Group 3 (E. coli and HPS vaccinated, winter season) (n = 358): The animals were analogously treated as Group 1. Group 4 (non-vaccinated, winter season) (n = 353): Piglets were not vaccinated. The following parameters were evaluated: A: average daily nursery weight gain (ADG), B: nursery mortality, C: feed efficiency (FE). No significant weight differences were detected within the vaccinated and non-vaccinated summer or winter raised groups of weaners. Summer raised weaners were significantly (P<0.05) heavier from day 35 on than winter raised animals. ADG and FE of summer raised pigs were significantly better (weeks 1-3 P<0.05; fourth week post-weaning P<0.01) during the nursery period than that of the winter raised groups. Winter raised vaccinated weaners showed during the last week of nursing significantly (P<0.05) better daily gain and feed efficiency compared with the non-vaccinated winter raised animals. Non-significant ADG and FE differences were detectable between the summer raised vaccinated or non-vaccinated groups of pig. Winter raised non-vaccinated animals suffered significantly (P<0.05) higher nursery mortality (10.63%) compared to the winter raised vaccinated animals. Implication: In cases of concurrent infections with HPS 5 and with different serotypes of E. coli, especially during winter season, vaccination against both diseases is suggested.     

Comparison between Haemophilus parasuis infection in colostrums-deprived and sow-reared piglets

The aim of this study was to compare the development of Glasser's disease in sow-reared and colostrum-deprived piglets. Ninety piglets from a commercial pig farm in Spain were used. The farm was positive for Haemophilus parasuis. Fifty-two pigs were sow-reared (SR) and 38 were colostrum-deprived (CD) piglets. The animals were intratracheally inoculated with H. parasuis serovar 5 and sacrificed at 1, 2 and 3 days post-infection. To assess the development of disease, antibody titers, clinical signs, pathological lesions, microbiological isolation and PCR amplification were compared between the groups. Inoculation of SR pigs did not cause clinical signs or lesions of Glasser's disease. In SR pigs, H. parasuis isolation and specific PCR amplification from tissues showed a very low number of positive samples. In contrast, in CD pigs, inoculation resulted in the typical signs and lesions of Glasser's disease. Positive microbiological isolation and specific PCR products were obtained from the majority of the tissues tested, and no antibodies against H. parasuis were detected. The experimental infection using CD pigs describes a successful method to study this microorganism and confirms the important role that maternal antibodies play in protection against clinical signs and disease.     

Relationship between serotype, virulence and SDS-PAGE protein patterns of Haemophilus parasuis

141 Haemophilus (H.) parasuis and 8 H. parasuis-like strains from different farms were serotyped according to Morozumi and Nicolet (1986 b) as well as to Bakos et al. (1952). It was possible to classify 72.8% of the investigated strains. 7 out of 12 serotypes have been described for the first time. The high specificity in the agar gel precipitation test was not reproducible in the more sensitive dot-blot procedure. The dot-blot results point to a participation of non-immunogenic polysaccharides in the detection reaction. The serotypes SV 1, SV 5, SV Jena 6 and SV Jena 10 proved to be highly virulent in SPF pigs, SV 2 and SV 4 were of medium virulence. The other serotypes were found to be nonvirulent. Unencapsulated strains and isolates of serotype SV 5 prevailed in animals with Glasser's disease. 23 H. parasuis and 3 H. parasuis-like strains were examined in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). On the basis of protein profiles of whole-cell lysates, 23 of them could be assigned to 5 groups. Apart from the highly virulent strains of serovar 1, which belonged to PAGE type III, all other highly virulent strains of the serovars SV 5, SV Jena 6 and SV Jena 10 were grouped into PAGE type I. No correlation could be found between PAGE type on the one hand and virulence or origin of isolates on the other hand.     

江西省部分猪场副猪嗜血杆菌病血清学调查

为调查江西省副猪嗜血杆菌病的流行情况,采集未进行疫苗免疫接种的11个猪场150份血清,应用间接血凝试验检测其抗体滴度,结果表明本地区副猪嗜血杆菌抗体总阳性率为44%,其中母猪阳性率偏高,说明该省猪场存在一定程度的副猪嗜血杆菌的感染.     

Prevalence of Streptococcus suis in four to eight week old clinically healthy piglets.

The study was undertaken to determine the prevalence, in the nasal cavities, of Streptococcus suis in four to eight week old clinically healthy piglets. Streptococci biochemically compatible with S. suis were isolated from 94% of piglets and 98% of farms. Of the 782 isolates submitted to serotyping, only 164 (21%) were included in the nine official serotypes. These 164 typable isolates originated from 121 (31%) of the 388 piglets and from 36 (73%) of the 49 farms included in the study. The most frequent serotypes found in piglets were, in decreasing order, 3, 4, 8 and 2. Serotype 1 was not detected in this survey. As many as 32% of piglets were found positive for two different serotypes and three different serotypes were found in 1%.     

Interaction of Haemophilus parasuis with nasal and tracheal mucosa following intranasal inoculation of cesarean derived colostrum deprived (CDCD) swine.

Twenty-three cesarean derived, colostrum deprived pigs were obtained at 5 wk of age and inoculated intranasally with either 1.4 x 10(8) colony forming units of Haemophilus parasuis or sterile phosphate buffered saline. Pigs were euthanized at 4, 8, 12, 18, 26, or 36 h post-inoculation and tissues from the oropharynx and respiratory tract were obtained for qualitative bacterial culture, immunohistochemistry for H. parasuis antigens, and light and transmission electron microscopy. Haemophilus parasuis was consistently isolated from the nasal cavity (17/17, 100%) and trachea (13/17, 76%) and rarely isolated from the lung (3/17, 18%) and blood stream (1/17, 6%) of infected pigs. Antigens of H. parasuis were sporadically detected on the nasal mucosa (6/17, 35%) and trachea (8/17, 47%). Light microscopic lesions included submucosal and intraepithelial infiltrates of neutrophils and infrequent, patchy loss of cilia. Ultrastructural changes in nasal mucosal epithelial cells included cell protrusion, loss of cilia, and dilation of the cytocavitary network. Bacteria were infrequently identified and were either within an amorphous material at the apical surface of the cilia or were between individual cilia. These results suggest H. parasuis associates with the nasal mucosa and can induce a suppurative rhinitis with nasal mucosal epithelial cell degeneration. This process may represent an initial event in the pathogenesis of H. parasuis infection of swine.     

Haemophilus parahaemolyticus serotypes. Serological response

Serotypes 1,2,4 and 5 of Haemophilus parahaemolyticus were inoculated into, respectively, 4,4,2 and 5 pigs. Serum samples were tested for circulating antibodies by the modified complement fixation test (CF test). When individual serotypes were used as antigen, titers were found only to the serotype which had been used for inoculation. Using antigen in which the serotypes were pooled, antibodies were demonstrated in sera from all the pigs. The CF titers obtained with the pooled antigen were equivalent to those found with each serotype separately. When the CF test was used for serological examination of field sera there was full agreement between the results obtained with the pooled antigen and those obtained with serotype 2 antigen alone. No cross reactions were found with the pooled antigen in herds that were sero-positive to Haemophilus parasuis, strain 4800. The experiment has shown that there is no serological cross reaction between serotypes 1, 2, 4 and 5 when they are used as antigen in the CF test. Also, the results imply that with a pool of the different serotypes of Haemophilus paralyticus as antigen similar results may be obtained as with the single serotype 2 antigen.     

副猪嗜血杆菌人工感染猪的病理学观察

用副猪嗜血杆菌分离株感染断奶仔猪,发病仔猪临床表现为体温中度升高、精神不振、被毛粗乱、站立不稳、厌食、呼吸困难。尸体剖检,可见胸腹腔纤维素渗出严重,有大量的渗出液、肺出血及脑充血等;病理组织学表现为,肺脏、心脏、脾脏等脏器含有大量的中性粒细胞的纤维蛋白性多发性浆膜炎、脑膜炎及支气管肺炎。结果表明,此分离株为一高致病潜力的菌株。     

Effect of vaccinating sows and their piglets on the development of Glässer's disease induced by a virulent strain of Haemophilus parasuis serovar 5

Ten pregnant gilts were divided into two groups of five and one group was vaccinated at 80 and 95 days of pregnancy with a commercial bacterin containing Haemophilus parasuis serovars 2, 3 and 5. Half the piglets born to each group of gilts were vaccinated at seven and 21 days of age with the same bacterin, and one week after they were weaned at five weeks, all the piglets were inoculated intratracheally with 10(6) colony-forming units of Hparasuis serovar 5. At slaughter, a significantly smaller percentage of the lungs of the pigs born to the vaccinated gilts was affected by pneumonic lesions, and significantly fewer of them had arthritic joint changes. The average daily liveweight gain of the pigs born to the vaccinated gilts was significantly greater than that of those born to the unvaccinated gilts, but the vaccination of the piglets had no effect. There was no significant difference between the feed conversion ratios of the four groups of piglets, and none between the average times they took to reach slaughter weight. The pigs born to the vaccinated gilts had higher ELISA titres to Hparasuis than those born to the unvaccinated gilts.     

副猪嗜血杆菌病疫苗研究进展

副猪嗜血杆菌病又称猪革拉泽氏病,副猪嗜血杆菌主要引起猪的多发性浆膜炎、纤维素性心包炎、关节炎和脑膜炎。目前预防该病主要是灭活疫苗,但不同血清型之间交叉保护性不强或无交叉保护作用。因此,发展新的广谱疫苗是未来的趋势。文章对副猪嗜血杆菌病的疫苗及其研究现状进行了分析综述。     

猪繁殖与呼吸综合征病毒NSP2基因不同变异毒株对仔猪致病性研究

为了评价猪繁殖与呼吸综合征病毒(PRRSV)不同分离毒株致病性差异,选择4株PRRSV分离毒株,即YX0907、BB0907、SY0909(属于NSP2基因亚型Ⅰ,具有30aa缺失特征)和NT0801(属于NSP2基因亚型Ⅱ,其NSP2上不存在缺失)进行动物接种试验。将23头45日龄PRRSV、猪圆环病毒2型和副猪嗜血杆菌阴性健康仔猪随机分为5组,第1～4组各5头猪,分别颈部肌内注射上述4株PRRSV分离株(均为第3代)2×104.32TCID50.(mL.头)-1,第5组3头猪作为空白对照,隔离饲养21d,每天观察临床症状。攻毒后不同时间测定病毒血症,并对死亡猪和第21天处死猪进行病理剖解、观察大体病理变化和组织病理变化。结果显示,BB0907毒株毒力最强,试验猪感染后体温明显升高,临床症状明显,可引起3/5死亡,病猪肺脏组织具有明显病理变化;YX0907毒株毒力较强,试验猪临床症状和病理变化明显,可引起2/5死亡;NT0801毒力较弱,部分试验猪感染后出现1～2d体温升高和轻度临床症状,未引起死亡;SY0909毒株毒力最弱,感染猪出现1～3d体温升高,临床症状不明显,病理变化较轻;而对照猪无临床异常表现和...