Induction of chicken interferon by avian infectious bronchitis virus.

The ability of nine strains of avian infectious bronchitis virus (IBV) to induce chicken interferon has been investigated using Semliki Forest virus for the tests. The Beaudette, H120 and Connecticut 46 strains induced interferon in the allantoic fluids of embryonated hens' eggs, the highest titre (1 : 30) being associated with Beaudette; but these as well as the Massachusetts M-41 and H52 strains failed to yield interferon in primary monolayer cultures of chick kidney cells as did all nine strains in organ cultures of chick embryo trachea. None of six strains of IBV investigated was susceptible to the inhibitory effects of chicken interferon.     

Phenotypical and genotypical characteristics of paired isolates of Pasteurella multocida from the lungs and kidneys of slaughtered pigs

Twenty-eight strains of Pasteurella multocida were isolated from 12 Danish and two Canadian abattoir pigs. Fourteen strains were isolated from pulmonary inflammatory lesions, and 14 strains were isolated from kidneys of the same animals. Phenotypical and genotypical characteristics of the strains were evaluated with a view to determine if P. multocida isolated from kidneys might have been disseminated from the lungs. All field strains were capsular type A. The biochemical reactivity in the API-20E and API-ZYM commercial test-kits was uniform with the exception of alpha-glucosidase activity which was present at low levels in only ten of the strains. One strain was markedly serum sensitive, six strains slightly sensitive and the remaining were serum resistant. The peptide patterns obtained by polyacrylamide gel electrophoresis of whole cell proteins of the strains were very uniform with the exception of differences in intensity of bands in the 38 and 34 kD regions. The pattern of oligonucleotides obtained after electrophoresis of total genomic DNA digested with BamHI showed that the paired isolates had identical patterns in eight of the 14 animals. It is therefore likely that isolates from kidney lesions represent blood borne dissemination from primary pulmonary lesions.     

The interaction between Newcastle disease virus and Escherichia coli endotoxin in chickens.

The interaction between Newcastle disease virus (NDV) and Escherichia coli endotoxin was studied in cell cultures, embryonated chicken eggs, and 8-wk-old chickens. These interactions were evaluated according to the induction of specific or nonspecific resistance in the host system and the virus titer produced in both chicken embryos and chickens. The endotoxin of E. coli induced a decrease in the size of the bursa of Fabricius in live chickens. Escherichia coli endotoxin given intravenously induced plasma antiviral activity in chickens that was interpreted to be interferon, as detected in a vesicular stomatitis virus plaque reduction assay. Endotoxin failed to produced toxic effects in the chicken embryo fibroblasts (CEFs) or to result in any antiviral effect because no change was noted in the number of NDV plaques formed in CEF cultures. When endotoxin was given 3 days before NDV exposure in chickens, the virus titers were significantly (P < 0.05) decreased from a peak of 10(2) to 10(0.18), 10(2.5) to 10(0.18), and 10(2.5) to 0 in the spleens, lungs, and kidneys, respectively, at 72 hr post-NDV inoculation. When endotoxin was given 24 hr after NDV inoculation, the NDV titer significantly (P < 0.05) increased from 10(2.0) to 10(3.5), 10(2.5) to 10(6.5), 10(2.5) to 10(4.5), 0 to 10(2.5) in the spleen, lungs, kidneys, and liver, respectively, at 72 hr after NDV inoculation. In chicken sera, hemagglutination inhibition (HI) titer to NDV was significantly (P < 0.05) enhanced from 1164 to 3127 when endotoxin was given prior to virus inoculation. However, there was a decrease in HI to NDV from 1164 to 727 without a significant difference in chicken sera when NDV was given prior to endotoxin inoculation.     

呼吸型鸡传染性支气管炎病毒的抗原定位与动态分布

应用间接免疫荧光抗体(IFA)和RT-PCR法对人工感染IBV-M41株的SPF鸡不同脏器中的病毒进行了跟踪检测。结果在感染后24h气管中最早出现特异性荧光，感染后第3h肺脏和肾脏出现特异性荧光，感染后第5d肝脏、脾脏、法氏囊、直肠等脏器也不同程度的出现特异性荧光，特异性荧光在气管中最强，持续时间也最长，可达14d或更长：在肺脏和肾脏可持续3～5d；而在其他器官持续1～3d。试验结果表明气管、肺脏、肾脏都是M41株病毒增殖的场所，但随感染时间的延长，病毒最终定位于主要的靶器官气管。IFA和RT-PCR方法均可以对IBV抗原定位，相对来说IFA法更直观，而RT-PCR更灵敏。     

鸡呼吸道致病菌的分离鉴定

本试验旨在为开发防制鸡细菌性呼吸道疾病产品提供依据。本试验将患有呼吸道疾病的鸡病料如喉管、气管、肺脏组织接种到各种选择培养基分离细菌,对分离的17株菌株进行生化鉴定、PCR鉴定和致病力测定。结果显示,在伊红美蓝琼脂(EMB)培养基中分离出黑色金属光泽菌落;革兰氏染色后在光学显微镜下见到革兰氏阴性的短杆状细菌;PCR扩增出1 500 bp大小条带,测序结果与GenBank中细菌16S rDNA序列进行BLAST比对并构建系统进化树,分离菌最终鉴定为一株大肠杆菌。将分离的致病菌滴鼻感染肉鸡能损伤肉鸡呼吸道,使喉管出现血斑,气管红肿、布满血点,心脏、肝脏包裹黄色干酪样物质,气囊浑浊不透明,具有致病性。结果表明,分离的致病菌可作为产品开发的基础。     

Isolation and Identification of Respiratory Pathogens of Chicken

This study was aimed to provide the basis for prevention and control of development of a new product for bacterial respiratory disease of chicken.Diseased samples such as throat, trachea and lungs were inoculated on various selected media for isolating bacteria.17 isolated strains were identified by biochemistry assay and PCR, and then animal experiment were carried out.Black and glassy surface with metallic shine colony from EMB medium Gram-negative bacilli were observed under optical microscope.1 500 bp products were specifically amplified by PCR.DNA sequencing results were analyzed by BLAST and DNAStar with 16S rDNA sequence in GenBank.The results showed that the strains were identified as Escherichia coli.It could cause damage infection with the isolated bacteria through noses.Significant blood spots were observed on throat.Trachea was congestion, swelling and studded with blood points.Heart and liver were wrapped with yellow cheese substances.Air sac was yellow and opaque.The isolated bacteria could provide basis for developing a new product.     

Detection of avian infectious bronchitis viral infection using in situ hybridization and recombinant DNA

A recombinant DNA probe with specificity for the 3' end of genomic RNA from the Ark 99 strain of infectious bronchitis virus (IBV) was found to hybridize with extracted RNA of three strains with the Ark serotype, as well as the Mass41, Holl52, Gray, JMK, Conn, Fla and SE17 strains of IBV. Viral infection was detected in the cytoplasm of chicken embryo kidney cells inoculated with Mass41, Ark99, SE17 or two recent field isolates of IBV using in situ cytohybridization and a biotinylated probe. In vivo infections were detected in individual cells of tracheas and lungs 2,4, and 6 days after inoculation of chicks with Mass41 and Ark99. In situ hybridization of Ark99 infected tissue sections using 32P-dATP labelled probe indicated that more viral replication was present in the trachea on day 4 than either days 2 or 6; whereas more viral RNA was found in the lungs on day 6 than days 2 or 4 after inoculation.     

Respiratory microbiota of healthy broilers can act as reservoirs for multidrug-resistant Escherichia coli

This study aimed at evaluate the presence and to study characteristics of Escherichia coli in the respiratory system microbiota of healthy broilers. Trachea, air sacs, and lungs of 20 broilers were analyzed at 21 days of age, reared in experimental conditions, without receiving antimicrobials. E. coli strains were isolated and identified using conventional bacteriology through morphological and biochemical characterization. The production of bacteriocin-like substances, the presence of virulence-associated genes (VAGs) of APEC (Avian Pathogenic Escherichia coli) predictors, and the antimicrobial susceptibility were evaluated. E. coli was found in 85 % of the animals (17/20), in the trachea, air sacs or lungs; and it was not found in 15 % of the animals (3/20). A total of 34 isolates were recovered, 13 from the air sacs, 13 from the lungs, and 8 from the trachea, which showed no production of bacteriocin-like substances nor virulence genes associated with APEC. Most isolates, 59 % (20/34), showed resistance to at least one of the tested antimicrobials, and six multiresistant strains were identified. The results demonstrated that strains of E. coli were commensal of the respiratory microbiota, and that they did not present pathogenicity to the host, since there were no clinical signs of disease, macroscopic lesions in the organs of the evaluated broilers, production of bacteriocin-like substances, nor virulence-associated genes considered as predictors of APEC in bacteria. These strains of E. coli were mostly susceptible to antimicrobials. However, the occurrence of multidrug-resistant strains suggests that these animals can act as reservoirs of resistant to antimicrobials E. coli.     

Septicemic proteus infection in Japanese quail chicks (Coturnix coturnix japonica)

Proteus infection was incriminated as the cause of severe depression, coma, and high mortality in successive broods of quail chicks. The pathological lesions comprised congestion of lungs, liver, and kidneys and mucus exudation in the trachea. The organism, isolated from the heart blood and lungs of affected chicks, was identified on biochemical tests as Proteus mirabilis. Pathogenicity of the isolate was tested in young albino mice and week-old quail chicks, which succumbed to infection within 48 hours of inoculation. Association of P. mirabilis with septicemic disease in Japanese quails has apparently been demonstrated for the first time.     

Virulence and transmissibility of Mycoplasma gallisepticum

The virulence of 4 low passage strains of Mycoplasma gallisepticum obtained from different sources within Australia was studied by experimental infection of chickens. Strain Ap3AS, originally isolated from the air sac of a broiler chicken, produced severe air sac lesions following injection into the abdominal air sacs of 2-week or 3-week-old chickens, and adult hens. Strain 80083 which was isolated from a clinically normal broiler breeder hen was also capable of producing gross air sac lesions following intra-abdominal (IA) injection, although it did so less consistently than strain Ap3AS. Strain 82078 isolated from a layer hen and strain QXO which was isolated from a turkey were also moderately pathogenic in terms of the incidence and severity of lesions elicited following IA injection. Strains Ap3AS and 80083 both caused a substantial loss of egg production over a 5 week period after IA infection of 27-week-old hens. Neither strain Ap3AS nor 80083 caused gross lesions or loss of egg production when administered alone into the upper respiratory tract. However, when inoculated into the conjunctival sac in combination with the Vic S strain of infectious bronchitis virus (IBV) strains Ap3AS and 80083 produced identical clinical signs of conjunctivitis. The mean numbers of M. gallisepticum in tracheal washings were significantly higher 2 weeks after infection in the group receiving strain 80083 in combination with IBV than in the group infected with strain Ap3AS and IBV (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Nephritis associated with infectious bronchitis virus Cal99 variant in game chickens

Infectious bronchitis virus (IBV) Cal99 variant was isolated from the kidneys of seven 2-5-mo-old game chickens with nephritis and respiratory disease. IBV Cal99 variant is usually associated with respiratory disease in broiler chickens in California. Macroscopically, the majority of the birds had moderately to severely enlarged and mottled pale kidneys, with increased urates in the ureters. Microscopically, most of the birds had acute nephrosis and interstitial nephritis. The birds also had sinusitis, tracheitis, bronchopneumonia, airsacculitis, salivary gland adenitis, and lymphoid depletion in the thymus and bursa of Fabricius. Immunohistochemistry was strongly positive for IBV antigen in the cytoplasm of tubular epithelial cells in the kidneys and also in the epithelium of the respiratory tract, salivary glands, proventriculus, intestine, and bursa of Fabricius. Infectious bronchitis virus was isolated from the trachea, lungs, kidneys, and cecal tonsils. Sequencing of the hypervariable region of the S1 gene of the kidney IBV isolate, designated IBV/CA99variant/07, revealed that the virus was 98% homologous to the Cal99 serotype of IBV.     

Prevalence of various phenotypes of Streptococcus suis isolated from swine in the U.S.A. based on the presence of muraminidase-released protein and extracellular factor.

The present study describes the prevalence of muraminidase-released protein (MRP) and extracellular factor (EF) proteins associated with virulence of Streptococcus suis serotype 2 from a collection of USA strains. Sixty-six strains belonging to serotypes 1, 2, 3, 4, 7, and 10, were analyzed with a set of double antibody sandwich ELISAs and Western blots. Nineteen of 34 serotype 2 strains from cases of swine meningitis had the MRP+EF+ phenotype. Five of 7 serotype 2 strains isolated from lungs had an MRP*EF- phenotype. An MRP-EF+ phenotype was found in 4/34 strains isolated from swine meningitis. The MRP*EF- and MRP-EF+ phenotypes have not been reported previously. All strains of serotypes other than 2, including isolates from cases of meningitis, had the MRP-EF- phenotype, suggesting that these strains must have other, as yet undetected, virulence factors.     

Characterization of two strains of fowl adenovirus type 1

An adenovirus isolated from the trachea of a chicken with respiratory disease was compared with an isolate obtained from the trachea of a clinically normal chicken. The isolates caused similar respiratory disease experimentally but differed in plaque morphology and fluorescent-antibody reactions in infected chick embryos.     

1株鸡传染性喉气管炎病毒的基因组特征与致病性

本研究旨在了解我国鸡传染性喉气管炎病毒(ILTV)流行毒株的分子特性.对1株分离自国内养殖场的鸡传染性喉气管炎病毒毒株BT株进行了部分基因序列(TK、ICP4、gB、UL32)测定分析,并研究了其对2周龄SPF鸡的致病性.遗传进化分析表明,BT株核苷酸序列与国内其他流行毒株相似性在97％以上,属于同一进化分支,未出现较...     

Porcine adenoviruses. Isolation and cytopathogenic examination of four serological types

The first report of the isolation of adenovirus from a pig was that of Haig et al. in 1964. The virus was isolated from faeces and was serologically different from many of the common human adenoviruses. In Denmark, six strains have been found in organ material from pigs (Rasmussen 1966). In the USA Kasza (1966) isolated an adenovirus from the brain of a pig with encephalitic symptoms, and in West Germany the virus was demonstrated in tissue culture of pig kidney from a group of animals where up to every tenth kidney was found to be infected (Mahnet & Bibrack 1966).The present study deals with virus strains isolated from non-inoculated cell cultures or from normal or diseased pigs. It includes a serological classification of strains isolated from organ material and a study of the cytopathogenic effect of the viruses in cell cultures of the kidneys and lungs of pig embryos and of the kidneys of bacon pigs and calves.     

Isolation and molecular analysis of colonising and non-colonising strains of Campylobacter jejuni and Campylobacter coli following experimental infection of young chickens

Fourteen-day-old chickens were inoculated with selected Campylobacter coli and C. jejuni strains. C. jejuni strains were of two subgroups based on a polymorphism detected using a DNA probe and represented the profiles typical for the majority of strains of either chicken or human origin. All C. coli strains previously isolated from humans colonised chickens, whereas from 4/7 C. jejuni strains of human origin, failed to colonise. Of 12 Campylobacter strains of chicken origin, 10 established a persistent colonisation in the chickens, and 2 strains colonised poorly or not at all. Four strains that failed to colonise chickens were each inoculated into groups of five birds. Three strains again did not colonise any of the chickens and the fourth strain colonised four out of the five chickens, but was poorly excreted. When infected chickens were placed in the same enclosure to facilitate interchange of strains, C. jejunistrain 331 was found to be dominant and colonised all 12 chickens by 21 days, displacing all other strains. C. jejuni strain 331, was then inoculated into groups of five birds with previously established colonisation by C. jejuni and C. coli strains. Strain 331 was able to replace the C. jejuni strain in all five birds but established co-colonisation with C. coli strain. Naturally occurring co-colonisation by two C. jejuni strains was detected in one chicken out of 200 tested. There was no obvious correlation between the type of DNA polymorphism in strains of chicken origin and their ability to colonise chickens.     

Mastitis severity induced by two Streptococcus uberis strains is reflected by the mammary immune response in vitro

Streptococcus uberis is the most common environmental mastitis pathogen causing udder inflammations of different severities in dairy cows. The aim of the study was to investigate if the different clinical outcome of mastitis induced by different strains of S. uberis can be reflected in the mammary immune response. Mammary epithelial cells and somatic milk cells were treated with heat inactivated and living S. uberis of strain A and strain B in vitro. Strain A was repeatedly isolated from a chronically infected quarter during 8 months, and persisted in the quarter despite antibiotic treatment. Strain B caused an acute clinical mastitis and was not further isolated after a single antibiotic treatment. Treatment with Strain B induced a more pronounced increase of mRNA-expression of various immune factors (interleukin-8, interleukin-1beta, RANTES, and lactoferrin) in mammary epithelial cells than strain A. In contrast to mammary epithelial cells the response of removed somatic milk cells showed no differences between the stimulation with two S. uberis strains. Tumor necrosis factor-alpha mRNA expression was not differently induced by the two strains. In conclusion, the characteristics of different severities of mastitis that are induced by different S. uberis strains in vivo can also be reflected at the level of the immune response of the mammary gland in vitro.     

Experimental avian paramyxovirus serotype-3 infection in chickens and turkeys

Avian paramyxoviruses (APMV) are divided into nine serotypes. Newcastle disease virus (APMV-1) is the most extensively characterized, while relatively little information is available for the other APMV serotypes. In the present study, we examined the pathogenicity of two divergent strains of APMV-3, Netherlands and Wisconsin, in (i) 9-day-old embryonated chicken eggs, (ii) 1-day-old specific pathogen free (SPF) chicks and turkeys, and (iii) 2-week-old SPF chickens and turkeys. The mean death time in 9-day-old embryonated chicken eggs was 112 h for APMV-3 strain Netherlands and > 168 h for strain Wisconsin. The intracerebral pathogenicity index in 1-day-old chicks for strain Netherlands was 0.39 and for strain Wisconsin was zero. Thus, both strains are lentogenic. Both the strains replicated well in brain tissue when inoculated intracerebrally in 1-day-old SPF chicks, but without causing death. Mild respiratory disease signs were observed in 1-day-old chickens and turkeys when inoculated through oculonasal route with either strain. There were no overt signs of illness in 2-weeks-old chickens and turkeys by either strain, although all the birds seroconverted after infection. The viruses were isolated predominantly from brain, lungs, spleens, trachea, pancreas and kidney. Immunohistochemistry studies also showed the presence of large amount of viral antigens in both epithelial and sub-epithelial lining of respiratory and alimentary tracts. Our result suggests systemic spread of APMV-3 even though the viral fusion glycoprotein does not contain the canonical furin proteases cleavage site. Furthermore, there was little or no disease despite systemic viral spread and abundant viral replication in all the tissues tested.     

部分省市猪群猪流感的血清学调查及猪流感病毒的分离与鉴定

对黑龙江、吉林、辽宁、安徽、山东、内蒙、河南、河北、江苏、安徽、浙江、湖北、福建、广东、海南、上海等省、市猪群进行了猪流感的血清学和病原学调查研究。从 130 6份猪鼻棉拭子样品和死亡猪肺、气管样品中分离到 39株H3N2亚型猪流感病毒 ,12株 H1亚型猪流感病毒及其它亚型猪流感病毒 ,病毒粒子在透射电镜下呈现典型的正粘病毒特征 ,有囊膜和纤突 ,多为椭圆形、圆形、或杆形 ,直径约 80～ 12 0 nm。对 1997- 2 0 0 1年 3895份猪血清的血清学调查结果表明 ,近年中国多个地区猪群存在抗SWTN77(H1)、SWCO77(H3)、DKAT6 9(H1)、TKUK6 3(H3)流感病毒抗体 ;1998年来自河北的猪血清中抗 SWTN77阳性率高达 33.3% ;1999年来自内蒙的猪血清中抗 TKUK6 3和SWCO77阳性率分别为 13.3%和 2 6 .7% ;2 0 0 0- 2 0 0 1年调查的所有省市的猪群中均存在抗SWCO77抗体 ,阳性率从 3.2 %～ 10 0 %。说明近年我国猪群中 H3亚型猪流感的污染相当普遍     

猪链球菌2型的分离鉴定及致病性试验

从全国部分猪场采集疑似猪链球菌感染病例脑样品20份进行细菌分离,成功分离到10株细菌,通过猪链球菌及血清类型鉴定,最终确定其中一株为2型猪链球菌。应用猪链球菌7种主要毒力因子特异性基因扩增检测方法检测所分离到的2型猪链球菌的毒力因子分布情况,并应用小鼠攻毒试验对其致病性进行观察研究。结果表明:分离的2型猪链球菌具备7种毒力因子;动物试验表明SS2能引起小鼠的急性败血症及脑膜炎;细菌回归试验结果表明,试验组死亡小鼠的脑、心脏、肝脏、脾脏、肺脏、肾脏均有细菌定植,且能分离出攻毒菌。此分离菌株的研究为研制2型猪链球菌病疫苗奠定了基础。