猪肺炎霉形体对培养基中的新生仔猪气管环纤毛的损害作用

据报导,猪肺炎霉形体对猪气管粘膜纤毛有损害作用,将猪肺炎霉形体接种于猪胚气管环和肺单层细胞上培养,它能使上皮细胞纤毛损害脱落;将接种猪肺炎霉形体无菌猪的气管和支气管作电镜扫描,观察到霉形体的早期感染存在于纤毛上皮细胞,在气管     

鸡毒霉形体油乳剂灭活苗对实验攻毒蛋用鸡产量的影响

将３０只２０周龄鸡毒霉形体（ＭＧ）阴性的蛋用种鸡分为４组，攻毒有Ⅰ组于颈部皮下接种２次油乳剂灭活苗；Ⅱ组免疫接种１次；Ⅲ组于攻毒后１周免疫接种１次，Ｃ组不接种疫苗，为对照线。４组鸡均在２９周龄是攻击ＭＣ致病株ＢＧ４４Ｔ。攻毒后通过７周观察，发现３个免疫组鸡的产蛋量下降率均明显低于对照组。攻毒后第７周剖杀Ⅰ组和对照组的全部鸡进行ＭＧ的分离培养，结果从对照组鸡的气管、肺和气囊中均分离到了ＭＧ，而Ⅰ组仅在气管和肺中分离到ＭＧ。２组鸡的输卵管中均未分离到ＭＧ。     

鸡毒霉形体人工感染肉用仔鸡后呼吸系统的病理形态学观察

７日龄健康肉用仔鸡气囊接种毒霉形体ＨＳ２心株,３－５ｄ后出现典型的ＭＧ感染症状,其呼吸系统发生一系列病理组织学变化。采集感染鸡及对照鸡的气管经固定,脱水,临界点干燥,镀金后置于扫描电镜下观察,可见感染鸡气管粘膜明显水肿,纤毛部分或全部脱落等,而对照组鸡气管则无任何病变;光镜下可见感染鸡的气管粘膜水肿增厚１－２倍,粘膜下层单核白细胞聚集,其间有数量不等的淋巴细胞集团,粘液细胞减少或消失;气囊粘膜水肿     

鸡的霉形体病及其防治

１病原霉形体是一种分布广泛的类胸膜肺炎微生物,经常存在于患有寄生虫病或其他疫病的人、禽类和其他动物的粘膜上。禽类的霉形体通常分１０个血清型。但只有鸡败血霉形体（以下简称ＭＧ）和滑膜霉形体（以下简称ＭＳ）对鸡有致病性。火鸡对ＭＳ的易感性比鸡更强。野鸡和...     

控制鸡霉形体病的新思路

鸡的霉形体病是由鸡败血霉形体（ＭＧ）和滑膜霉形体（ＭＳ）引起的。鸡败血霉形体主要感染鸡。火鸡,也感染其他禽类,引起呼吸道疾病。在鸡群中长期流行,使母鸡产蛋下降。因此鸡败血霉形体对家禽生产危害最大。 鸡的慢性呼吸道病（ＣＲＤ）是由败血霉形体（ＭＧ）引起的。本病全年都可发生,但以冬天和早春多发,单纯ＭＧ感染,在正常的饲养管理条件下,常不表现症状,呈隐性经过,一般只有轻度呼吸道症状,此时发病率高,死亡率在 １０％－ ３０％。当气候突变、营养不良（如维生素Ａ缺乏）、饲养密度过大、舍内氨气浓度过高、育雏舍温…     

精氨酸霉形体和莱氏无（需）胆甾醇霉形体在鸡胚细胞内增殖的比较观察

将精氨酸霉形体（Ｍｙｃｏｐｌａｓｍａａｒｇｉｎｉｎｉ，简称ＭＡ）和莱氏无（需）胆甾醇霉形体（Ａｃｈｏｌｅｐｌａｓｍａｌａｉｄｅａｗｉｉ，简称ＡＬ），分别接种于鸡胚细胞，电镜下观察结果如下：（１）此２种霉形体在形态、细胞内分布、增殖形式和吞噬功能以及对培养细胞的选择性等方面是相同的；（２）此２种霉形体引起培养细胞的病理学过程不同。接种ＭＡ的鸡胚细胞，早期即出现髓膜样结构和脂质体等退行性变化，晚期在细胞质内才能见到空泡出现；而接种ＡＬ的鸡胚细胞，早期即可出现细胞质内的空泡化现象，晚期细胞质内才可见到髓膜样结构和脂质体。     

应用聚合酶链反应检测鸡毒霉形体和滑液霉形形体的研究

利用鸡毒霉形体与滑液霉形体基因一定区域互补的序列,合成能分别对ＭＧ和ＭＳ目的基因的２对引物。和这２对引物对１０个国际标准的ＭＧ与ＭＳ菌株ＤＮＡ模板进行ＰＣＲ扩增,结果均得到与预期大小相一 的约７３２ｂｐ（ＭＧ）和２０７ｂｐ（ＭＳ）的ＰＣＲ产物。     

精氨酸霉形体和莱氏无（需）胆甾醇霉形体在鸡胚细胞内增殖的比较…

将精氨酸霉形体和莱氏无（需）胆甾醇霉形体，分别接种于鸡胚细胞，电镜下观察结果如下：（１）此２种霉形体在形态、细胞内分布、增殖形式和吞噬功能以及对培养细胞的选择性等方面是相同的；（２）此２种霉形体引起培养细胞的病理学过程不同。接种ＭＡ的鸡胚细胞，早期即出现髓模样结构和脂质体等退行性变化，晚期在细胞质内才能见到空泡出现；而接种ＡＬ的鸡胚细胞，早期即可出现细胞质内的空泡化现象，晚期细菌质内才可见到髓膜样     

鸡胚气管环纤毛对不同类型AIBV毒株的敏感性

以鸡胚气管环纤毛运动作指示系统,应用鸡胚气管环组织培养不同血清型的７个标准ＡＩＢＶ毒株及５个不同致病型的分离毒株。采用５０ＣＤ５０病毒量ＩＢＶ毒株感染鸡胚气管环培养物,观察感染后不同时间气管环纤毛的存活率。结果表明,鸡胚气管环纤毛对不同血清类型的ＡＩＢＶ毒株敏感性各具特征。     

鸡慢性呼吸道病的综合防治

鸡慢性呼吸道病的综合防治慢性呼吸道病（ＣＲＤ）是由鸡败血霉形体（ＭＧ）引起的一种以呼吸罗音、咳嗽、鼻漏及气囊炎为特征的鸡霉形体病。最常见于冬春季节，接种ＮＤ、ＩＢ、ＩＬＴ等疫苗及应激情况下常会诱发本病。该病不但可引起病鸡死亡，而且还会造成鸡的胴体等级...     

Decrease of the adhesion of Streptococcus suis serotype 2 mutants to embryonic bovine tracheal cells and porcine tracheal rings.

Streptococcus suis is an important swine pathogen that may be present in the tonsils of pigs that show no signs of illness. Because adhesion to host cells may be important in the carrier state, this study was undertaken to investigate adhesion to host cells by S. suis mutant strains defective in expression of a 39-kDa protein. Mutant strains of S. suis were generated by transposon Tn916 mutagenesis and were tested for adhesion to embryonic bovine tracheal cells and porcine tracheal rings. Compared with the parent strain, there was a significant reduction in adherence of 3 mutant strains to both bovine tracheal cells and porcine tracheal rings.     

Evaluation and comparison of various PCR methods for detection of Mycoplasma gallisepticum infection in chickens

Four genetic Mycoplasma gallisepticum (MG) polymerase chain reactions (PCRs) (16s rRNA PCR, three newly developed PCR methods that target surface protein genes [mgc2, LP (nested) and gapA (nested)]) were compared for analytical specificity and sensitivity and for diagnostic sensitivity (Se) and specificity of detection from tracheal swabs. The licensed MG DNA Test Kit Flock Chek test (IDEXX, Laboratories, Inc., Westbrook, ME) was as well evaluated for the diagnostic specificity and sensitivity of detection from tracheal swabs. Analytical specificity was evaluated for the four generic PCR methods using a panel of DNA samples from microorganisms that may be isolated from the trachea of commercial poultry and other fowl. PCR methods mgc2, nLP, and ngapA only amplified DNA from MG, whereas 16S rRNA PCR amplified DNA from MG and Mycoplasma imitans. The analytical sensitivity of the four generic PCR methods expressed in color-changing units (CCU)/amplification reaction was estimated for each PCR method and ranged from 4 to 400 CCU/reaction; the sensitivities of single PCR methods 16S rRNA and mgc2 were estimated at 40 CCU/reaction, the nLP at 400 CCU/reaction, and the ngapA at 4 CCU/reaction. The diagnostic sensitivity and specificity of MG detection from tracheal swab pools, as compared to isolation from choanal cleft swabs, was evaluated for the five PCR methods using three groups of birds exposed to vaccine strains ts-11 and 6/85 and to challenge strain R. All PCR methods were able to detect the vaccine strains and the challenge strain R directly from tracheal swabs, indicating that PCR primers from the different methods amplified divergent MG strains. Isolation and PCR results correlated satisfactorily among the three experimentally infected groups, with agreement values (k) ranging from 0.52 to 1.00. The ngapA, IDEXX, and mgc2 PCRs showed the best sensitivity (Se) ratios for detection of M. gallisepticum strains as compared to isolation. Compared to the ngapA and IDEXX PCR methods, the mgc2 PCR has a faster turnaround time, since this test consists of a single amplification reaction and the amplification product is detected by gel electrophoresis. Therefore, among the PCR methods evaluated in this study, the mgc2 PCR is the method of choice to further validate in the field.     

Demonstration of Mycoplasma gallisepticum in tracheas of healthy carrier chickens by fluorescent-antibody procedure and the significance of certain serologic tests in estimating antibody response

Chickens naturally infected with Mycoplasma gallisepticum (MG) were cultured by tracheal swab. Although the chickens showed no signs of disease, they remained MG carriers many months after the acute phase of infection. When MG was isolated from tracheas, the agent was demonstrated also in smear preparations from tracheal mucus by the indirect fluorescent-antibody procedure. Humoral immune response to MG was low, as detected by rapid serum-plate-agglutination, micro-tube-agglutination, hemagglutination-inhibition, and agar-gel-precipitation tests. Antigens prepared from three different MG strains gave variable results on the same serum samples. Homologous or heterologous sera obtained from the tested chickens did not inhibit the growth of MG previously isolated from the tracheas.     

Use of mgc2-polymerase chain reaction-restriction fragment length polymorphism for rapid differentiation between field isolates and vaccine strains of Mycoplasma gallisepticum in Israel

Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for a rapid test for differentiation of MG field strains from the live vaccine strains ts-11 and 6/85. We examined the differentiating potential of diagnostic polymerase chain reaction (PCR) primers targeted to the gene mgc2, encoding a cytadherence-related surface protein uniquely present in MG. The mgc2-PCR diagnostic primers are specific for MG in tests of all avian mycoplasmas or bacteria present in the chicken trachea and are sensitive enough to readily detect MG in tracheal swabs from field outbreaks. Differentiation of vaccine strain ts-11 was based on identification of restriction enzyme sites in the 300-base-pair (bp) mgc2-PCR amplicon present in ts-11 and missing in MG isolates from field outbreaks in Israel. Restriction sites for the enzymes HaeII and SfaN1 were identified in the amplified region in strain ts-11 and were not found in 28 field isolates of MG, comprising a representative cross section of all the MG isolates from the period 1997-2003. In practice, differential diagnosis of MG is achieved within 1 day of submission of tracheal swab samples by mgc2-PCR amplification and restriction of the amplicon with HaeII, giving a 270-bp fragment for ts-11 or no restriction for other MG strains tested. Application of the mgc2-PCR-restriction fragment length polymorphism (mgc2-PCR-RFLP) assay enabled differential diagnosis of both components of a mixture of ts-11 and non-ts-11 DNA, detecting the field strain in the presence of a large excess of ts-11. The test was successfully applied in vivo for monitoring vaccinates in a ts-11 vaccine trial. In principle, the test may also be used to identify the 6/85 vaccine strain, which yields a 237-bp product, readily differentiated from the approximately 300-bp PCR product of all other strains tested. Further testing of field isolates will be necessary to determine the applicability of this test in the United States and other countries.     

A quantitative study of single and mixed infection of the chicken trachea by Mycoplasma gallisepticum

The interaction between Mycoplasma gallisepticum (MG) and the tracheal mucosa of the young chicken was studied. The use of a selective plating method permitted differentiation between a pathogenic tylosin-resistant strain (227) and a less pathogenic tylosin-sensitive vaccine strain (F). Both MG strains adhered to the tracheal mucosa and colonized equally well. In mixed infection, the presence or absence of the second strain did not change the efficiency of colonization by either strain. When chickens were exposed to the vaccine strain 24 hr or 2 weeks before superinfection by the pathogen, there was no significant reduction in the efficiency of superinfection, despite the presence of 10(6) colony-forming units of MG strain F in the trachea. However, chickens had an increased ability to resist superinfection 5 weeks after exposure via the air sac. These results suggest that the biological mechanism underlying protection of F-strain-vaccinated chickens against adventitious infection by the homologous species does not involve competition for adherence sites or blockage by prior colonization.     

Antibody responses in sera and respiratory secretions from chickens infected with Mycoplasma gallisepticum

Antibodies in sera and respiratory secretions from chickens infected with Mycoplasma gallisepticum (MG) were measured by an enzyme-linked immunosorbent assay (ELISA). Chickens intratracheally inoculated with 10(5) cells of MG showed a correlation between severity of tracheal lesions and extent of MG colonization in the tracheas in the first 3 weeks postinoculation. Antibody titers in tracheal washings (TWs) of the infected chickens increased during this phase. Thereafter, isolation of MG from the trachea decreased sharply, and there was a concomitant decrease in tracheal lesion scores. At 5 weeks postinfection, the chickens that recovered from the infection exhibited a consistent presence of antibodies in TWs. Chickens reexposed had a faster rate of MG elimination and substantially less severe inflammatory lesions in the tracheas than chickens observed after the first exposure. These findings suggest a possible role of antibodies of the respiratory secretions in resistance to MG. The ELISA was a sensitive and reliable test to detect a minute amount of antibodies in the secretions.     

Permanent Tracheostomy in Standing Horses: Technique and Results

Permanent tracheal stomas were created in seven sedated, standing horses with severe upper airway obstruction. After local anesthesia, a 3-cm by 6-cm rectangle of skin was removed from the ventral surface of the neck, 3 cm distal to the cricoid cartilage. The sternothyrohyoideus muscles were clamped proximally and distally, then transected to expose the tracheal rings. The ventral third of four tracheal rings was dissected from the tracheal mucosa that was then incised in a double "Y." Two layers of suture were used to achieve mucocutaneous closure. Stomas healed without serious complications; two mares subsequently foaled, and three horses were used for riding.     

Evaluation of protection against Mycoplasma gallisepticum infection in chickens vaccinated with the F strain of M. gallisepticum

The effect of vaccination with the F strain of Mycoplasma gallisepticum (MG) on protection against challenge with a tylosin-resistant strain of MG was evaluated. White leghorn chickens vaccinated via eyedrop at 6 weeks of age were subsequently challenged with various dilutions of the tylosin-resistant MG strain, as were unvaccinated controls. Three days later, tracheal swabs were collected and cultured in medium with and without tylosin to distinguish between the vaccine and challenge strains. The mean infectious dose of the challenge strains was 3.8 log10 higher in the vaccinated group than in the controls, and the vaccinated group harbored fewer challenge organisms in the trachea. These findings suggest that the F strain of MG induces protection against infection with field strains of MG and that long-term vaccination with the F strain in multiple-age layer farms may result in replacement of field MG strains by the F strain.     

鸡大肠埃希氏菌菌毛表达、血凝谱及粘附特性研究

对６株具有不同致病性的鸡大肠埃希氏菌分离株体外菌毛的表达、对１３种不同红细胞血凝谱及血凝方式、对鸡胚成纤维细胞（ＣＥＦ）及在体内外对１日龄鸡气管组织的粘附特性进行了研究,结果表明,具有致病性的菌株,在体外适宜的条件下,能表达菌毛,非致病性菌株不表达。不同菌株的血凝谱及血凝方式具有差异,除中等致病性菌株ＭＧ３０e对大鼠红 细胞（ＲＢＣＦ）的凝集不能被Ｄ－甘露糖抑制,表现为抗甘露糖型血凝（ＭＲＨＡ）外,     

Scanning electron microscopic studies of Mycoplasma gallisepticum infection in embryonic tracheae

Mycoplasma gallisepticum (MG) was used to infect chicken embryos, and scanning electron microscopy was used to examine the morphologic changes in the tracheae. Tracheae harvested from embryos infected with MG for 5 days showed extensive deciliation, surface erosion, and inflammatory cell infiltration. Embryonic tracheal explants infected with MG for 6 hr showed the same deciliation and surface erosion. The damage to the tracheal surface caused by MG at the embryonic stage might play a role in the pathogenesis of MG infection.