混合感染中鸡毒支原体和副鸡嗜血杆菌的分离鉴定

从冀南地区某养鸡场患呼吸道疾病的病鸡群采集5份样品（气管和眶下窦分泌物）中，同时分离到鸡毒支原体和副鸡嗜血杆菌两种病原体。通过病原的分离培养、细菌L型检验、生化试验、血清学试验等鉴定，证明分离的鸡毒支原体与国际标准株S6的血清型一致，副鸡嗜血杆菌的血清型为A型，动物试验表明，分离的鸡毒支原体和副鸡嗜血杆菌均具有明显的致病性，说明该病鸡群同时混合感染了鸡毒支原体和副鸡嗜血杆菌。     

鸡传染性鼻炎的诊断

鸡传染性鼻炎是由细菌引起的一种以面部肿胀、流鼻涕为特征的急性上呼吸道传染病,本病病原副鸡嗜血杆菌通常分为A、B、C 3个血清型[1],且3型均可致病.迄今为止,在我国鸡群中尚未发现有B型副鸡嗜血杆菌感染的证据,多年来,A型副鸡嗜血杆菌一直是我国鸡传染性鼻炎的主要致病菌型,而由C型菌引起的鸡传染性鼻炎少见报道.1998年冬,山东某鸡场发生了一起以肿头为特征的疾病,经作者诊断,认为是鸡传染性鼻炎,而且可能由C型副鸡嗜血杆菌引起.有关情况报告如下.     

锦州地区鸡传染性鼻炎的流行病学调查

对发生过鸡传染性鼻炎的8个鸡场,从病史调查、现场调查、临床检查、病理剖检、细菌分离鉴定、血清定型、动物致病性试验、药物敏感试验以及防治等方面进行了较为详细的研究。结果表明,锦州地区鸡传染性鼻炎的发病率为5.2%～40.7%,死亡率约为1%～3%。分离获得8株副鸡嗜血杆菌,血清型主要为A型,个别为C型,未发现B型。不同时间分离的副鸡嗜血杆菌对抗菌药物的敏感性不同。     

秋冬交替季节鸡常见病的防治

一鸡传染性鼻炎1病原及流行特点本病是由副鸡嗜血杆菌引起的一种鸡的急性上呼吸道传染病。副鸡嗜血杆菌属于革兰氏阴性菌,有A、B、C三个血清型。前几年,我国流行的血清型主要是A型和零星C型,但近年来主要血清型是A和B型,且A型已经出现变异,发病比例有明显增加的趋势。     

青岛地区鸡传染性鼻炎病原株的分离,鉴定与定型研究

1993年青岛市周围一些鸡场相继发生了传染性鼻炎，为确诊本病，从一些鸡场选发病典型鸡，进行了细菌分离和鉴定试验，获得副鸡嗜血杆菌4株，按Kume等人方法作血清学定型，所有分离株被定为C型。     

副鸡嗜血杆菌的分离鉴定及16SrRNA序列分析

从云南省和四川省规模化养鸡场鸡传染性鼻炎疑似病例鸡鼻窦分离到2株革兰氏阴性小杆菌,并对其进行生化鉴 定、PCR鉴定和16SrRNA序列比对鉴定.16SrRNA分析表明两分离株与GenBank中的其他副鸡嗜血杆菌(Haemophilus paragallinarum,HPg)参考株核苷酸同源性为94.2％～99.2％.两分离菌株鉴定为副鸡嗜血杆菌,分别命名为YNAN20120110和SCPZH20120120株.16SrRNA遗传进化关系表明:分离株与NAD非依赖型副鸡嗜血杆菌血清A型代表株GU951543(HP105strain)的16SrRNA序列位于一个分支上,遗传进化关系最近,它们之间的核苷酸同源性为99.2％;与副鸡嗜血杆菌血清A型参考株AY498867(0083株)核苷酸同源性为96.9％.致病性实验表明分离菌株对成年产蛋鸡有强致病性.抗生素药物敏感试验表明:分离菌株对头孢吡肟、头孢噻吩、氯霉素、卡那霉素和氧氟沙星高敏,对四环素中敏,对磺胺甲唑耐药.     

秋冬交替季节鸡常见病的防治

秋冬交替季节,凉风、冷风多,昼夜温差大,是鸡禽流感、新城疫、传染性支气管炎、鼻炎等传染病的易发季节,需要格外引起重视。1 鸡传染性鼻炎1.1 病原及流行特点 本病是由副鸡嗜血杆菌引起的一种鸡的急性上呼吸道传染病。副鸡嗜血杆菌属于革兰氏阴性菌,有A、B、C三个血清型。前几年,我国流行的血清型主要为A型和零星C型,但近年来多为A和B型,且A型已经出现变异,发病比例有明显增加的趋势。本病潜伏期短、传播快,每年11月份到来年5月份期间发病多。     

副鸡嗜血杆菌分离鉴定血清学定型研究

通过流行病学调查，发展我省有鸡传染性鼻炎流行，采集试验样品３０５份，分离得副鸡嗜血杆菌１０２株，分离率３３．４％。根据Ｐａｇｅ的凝集试验分型方案，对１０２株副鸡嗜血杆菌分别与Ａ，Ｂ，Ｃ三种标准血清定型，有６４株菌定为Ａ型占６２．７％，其余３８株为Ｃ型占３７．３％。从流行地区的型别分布来看，有６个地区是Ａ型和Ｃ型均有流行占３７．５％，Ａ型或Ｃ型单独流行的地区各有５个，各占３１．２５％。研究结果对研制     

A型副鸡嗜血杆菌河南株的分离鉴定

从河南某发生肿头、流泪、流涕等呼吸道症状的蛋鸡发病场分离到1株细菌,结合临床症状、分离培养和PCR实验等,初步确定为副鸡嗜血杆菌。23SrRNA基因测序结果显示该菌与副鸡嗜血杆菌A型疫苗株C-Hpg-8株(CVCC254)99.6%同源,通过血清型凝集试验证实为A型,为本省副鸡嗜血杆菌的防治提供了科学依据。     

A型副鸡嗜血杆菌(山东株)的分离与鉴定

2011年11月,山东某肉鸡场发生以肉鸡眼睑及眶下窦周围明显肿胀为主要特征的传染性疾病。从采集的发病鸡眶下窦中分离到1株细菌,根据发病鸡群的临床症状、细菌的分离培养、形态观察、过氧化氢酶试验、革兰氏染色、动物回归试验、免疫攻毒试验和PCR等方法初步鉴定为副鸡嗜血杆菌(Hpg)。此外通过分离菌株的水平传播试验结果表明,造成该鸡场Hpg的水平传播和鸡传染性鼻炎的反复发作与饲养密度有很大的关系。最后将分离菌株送匈牙利诗华研发中心进行分型鉴定,确定为A型副鸡嗜血杆菌。根据分离地点将分离菌株命名为A型副鸡嗜血杆菌(山东株)。另外通过与GenBank已发表的Hpg基因序列进行同源性比对分析,结果显示,该基因序列与参考株的基因核苷酸序列同源性达99.0%。     

Relationship between infectivity and cytopathology for L-929 cells, membrane proteins, and antigenicity of avian isolates of Chlamydia psittaci

Seventeen isolates of Chlamydia psittaci from various avian species were examined. Based on their infectivity and cytopathology for L-929 cells, these isolates were separable into a high-infectivity group (HIG) and a low-infectivity group (LIG). Differences in the molecular weight of the major outer membrane proteins (MOMPs) of the isolates correlated with differences in infectivity. The HIG MOMPs had a molecular weight of 43,500, and the LIG MOMPs had a molecular weight of 45,500. The MOMP of one mammalian isolate of C. psittaci examined had a molecular weight of 43,500. Antisera raised against some of the isolates reacted with only the MOMP from isolates of their respective groups. The MOMPs of a mammalian C. psittaci isolate and of the C. trachomatis LGV 440 isolate did not react with HIG or LIG antisera. The MOMPs of some avian C. psittaci did react weakly with antiserum against the LGV 440 isolate of C. trachomatis.     

Characterisation of the first Australian isolate of Neospora caninum from cattle

OBJECTIVE: To isolate Neospora caninum from a congenitally infected calf. PROCEDURE: A calf was obtained from a N. caninum infected dam maintained in a dairy herd of Holstein-Friesian cattle located on the south coast of NSW near Nowra. The calf was euthanased and samples collected for serology and pathology. Samples of brain and spinal cord of the calf were homogenised and injected into immunocompromised mice in an attempt to recover protozoa by in vivo culture. Sequential passage of brain homogenate through IFNgammaPKO mice was performed and tissue culture flasks were inoculated with brain homogenate. Parasites were identified by electron microscopy and DNA sequencing. The antigen profile of the isolate was analysed using Western blotting. Pathogenicity was examined in BALB/c mice and transmission of the parasite during pregnancy was examined in Qs mice. RESULTS: The calf was seropositive for N. caninum and histopathological examination of sections of cerebrum identified lesions consistent with a very mild infection with N. caninum. The parasites isolated using tissue culture were identified as N. caninum, based on the sequence of the ribosomal DNA and electron microscopy. The antigen profile of the new isolate was similar to that of the NC-Liverpool isolate, but quite different from that of Toxoplasma gondii. In BALB/c mice inoculated with the new isolate, severe clinical signs developed in only three of ten infected mice, compared with six of ten mice infected with NC-Liverpool. Mild to moderate nonsuppurative encephalitis was observed in BALB/c mice infected with the new isolate, compared with mice infected with NC-Liverpool, that developed severe nonsuppurative encephalitis. Transplacental transmission of the isolate arising from an acute infection during pregnancy occurred in about 87% of pups. CONCLUSION: This is the first isolation of bovine Neospora caninum in Australia. This isolate, called NC-Nowra, appears to be a less virulent form and may prove to be a suitable candidate for vaccine development.     

Comparative studies of United Kingdom isolates of swine vesicular disease virus

The characteristics of four United Kingdom isolates of swine vesicular disease (SVD) virus from 1981 to 1982 have been compared with those of an isolate obtained from the first outbreak of swine vesicular disease diagnosed in the United Kingdom in 1972. When the virus structural proteins were examined by polyacrylamide gel electrophoresis the four isolates from 1981-82 all had the same polypeptide pattern, which was different from that of the 1972 isolate. Immunodiffusion tests with the 1972 isolate and one 1982 isolate did not reveal any antigenic difference between the viruses but minor antigenic differences were shown by cross-neutralisation tests between the 1972 isolate and the four isolates from 1981-82. In experimentally infected pigs the 1972 isolate produced typical SVD lesions whereas the four more recent SVD viruses produced only very mild clinical disease. Clinical lesions scored numerically were four- to 10- and five- to 11-fold higher at seven and 14 days after infection for pigs infected with the 1972 isolate than with the four isolates from 1981-82. The serum of pigs infected with the 1972 isolate contained significantly higher levels of neutralising antibody than those of pigs infected with more recent isolates. The antibody titres of pigs with only primary lesions ranged from log10 1.9 to 2.8 and one clinically normal pig had a titre of log10 2.4 at 14 days after infection. Attention is drawn to the implication of these findings for SVD control policies based only on the recognition and reporting of clinical disease.     

Lack of toxicity of a non-sporidesmin-producing strain of Pithomyces chartarum in cell culture and when dosed to lambs

In New Zealand the fungus Pithomyces charturum normally produces sporidesmin, a mycotoxin, which is responsible for the hepatogenous photosensitisation disease known as facial eczema. Cultures from an isolate of P. charturum, which does not produce sporidesmin, were examined by cell culture and by dosing to lambs to determine whether other toxic metabolites were produced. Acute and long term toxicity studies were conducted with the toxic response being assessed by weight changes, postmortem and histological examination of tissues, blood biochemistry and haematology tests. An extract from a sporidesmin-producing isolate was highly toxic in cell culture, while extracts of the nonsporidesmin-producing isolate did not cause a cytotoxic response to HEp 2 cells. After dosing with a sporidesmin-producing isolate, lambs developed liver lesions and clinical signs of facial eczema. Serum biochemistry changes occurred which were consistent with sporidesmin poisoning. Lambs dosed with the nonsporidesmin-producing isolate, at the rate of thirty times the number of spores of the sporidesmin-producing isolate, showed no observable toxic effects. All organs were of normal appearance, and histological examination of tissues, blood biochemistry and haematology results showed no abnormal changes. Similarly, long term dosing of extracts of the nonsporidesmin-producing isolate, at a rate equivalent to 100,000 spores/g of grass, produced no indication of a toxic response. It was concluded that the nonsporidesmin-producing isolate of P. churtarum contained no toxic metabolites in significant concentration.     

Comparative pathogenesis of serotype 1 and variant serotype 1 isolates of infectious bursal disease virus and their effect on humoral and cellular immune competence of specific-pathogen-free chickens

Specific-pathogen-free chickens inoculated with isolate VA (variant A) or isolate IM of infectious bursal disease virus (IBDV) were examined for mitogenic response to T-cell mitogens, primary and secondary antibody response to sheep erythrocytes and Brucella abortus, and gross and histologic lesions in thymus and bursa. Both isolates induced comparable depression in the mitogenic and antibody response, and both caused extensive gross and histologic lesions in the bursa of Fabricius. However, bursal necrosis induced by the IM isolate was accompanied by an inflammatory response, whereas the inflammatory component was lacking in the lesion induced by the VA isolate. Furthermore, the IM isolate induced extensive lesions in the thymus, but the VA isolate did not.     

A unique isolate of Malassezia from a cat

An isolate of Malassezia from a cat with otitis externa was examined mycologically as well as molecularly. The isolate was similar to M. sympodialis in morphological and biochemical characteristics. In molecular analysis, however, it differed from the 7 species of Malassezia previously reported. Therefore, this clinical isolate from a cat might be a new species of Malassezia.     

Report of isolations of unusual lyssaviruses (rabies and Mokola virus) identified retrospectively from Zimbabwe

Rabies isolates that had been stored between 1983 and 1997 were examined with a panel of anti-lyssavirus nucleocapsid monoclonal antibodies. Out of 56 isolates from cats and various wild carnivore species, 1 isolate of Mokola virus and 5 other non-typical rabies viruses were identified. The Mokola virus isolate was diagnosed as rabies in 1993 from a cat. Genetic analysis of this isolate suggests that it falls in a distinct subgroup of the Mokola virus genotype. The 5 non-typical rabies viruses were isolated from honey badgers (Mellivora capensis), African civets (Civettictis civetta) and an unidentified mongoose (Herpestidae). These isolates are representatives of rarely-reported wildlife-associated strains of rabies, probably maintained by the slender mongoose (Galerella sanguinea). These findings indicate that both Mokola virus and the mongoose-associated variant may be more common in Zimbabwe than is apparent from routine surveillance.     

Lack of toxicity of a nonsporidesmin-producing strain of Pithomyces chartarum in cell culture and when dosed to lambs

In New Zealand the fungus Pithomyces charturum normally produces sporidesmin, a mycotoxin, which is responsible for the hepatogenous photosensitisation disease known as facial eczema. Cultures from an isolate of P. charturum, which does not produce sporidesmin, were examined by cell culture and by dosing to lambs to determine whether other toxic metabolites were produced. Acute and long term toxicity studies were conducted with the toxic response being assessed by weight changes, postmortem and histological examination of tissues, blood biochemistry and haematology tests.

An extract from a sporidesmin-producing isolate was highly toxic in cell culture, while extracts of the nonsporidesmin-producing isolate did not cause a cytotoxic response to HEp 2 cells.

After dosing with a sporidesmin-producing isolate, lambs developed liver lesions and clinical signs of facial eczema. Serum biochemistry changes occurred which were consistent with sporidesmin poisoning.

Lambs dosed with the nonsporidesmin-producing isolate, at the rate of thirty times the number of spores of the sporidesmin-producing isolate, showed no observable toxic effects. All organs were of normal appearance, and histological examination of tissues, blood biochemistry and haematology results showed no abnormal changes. Similarly, long term dosing of extracts of the nonsporidesmin-producing isolate, at a rate equivalent to 100 000 spores/g of grass, produced no indication of a toxic response. It was concluded that the nonsporidesmin-producing isolate of P. churtarum contained no toxic metabolites in significant concentration.     

1株竹鼠奇异变形杆菌的分离鉴定及药敏分析

为确定广东某竹鼠养殖场发生竹鼠死亡的原因,本研究从发病竹鼠血液和组织中分离到可疑细菌,并对分离的菌株进行革兰氏染色、生化特性分析和16S rRNA基因鉴定及序列分析,同时进行药敏试验。结果显示:分离的细菌为杆状、球状和球杆状形状不一的革兰氏阴性菌;生化特性与奇异变形杆菌基本一致;16S rRNA序列与NCBI数据库中奇异变形杆菌16S rRNA核苷酸相似性为99%以上。结果表明,该分离细菌为奇异变形杆菌将其命名为GD/ZS-01株;药敏实验显示,该菌株对头孢哌酮、丁胺卡那和左氧氟沙星高度敏感。本研究结果为竹鼠养殖场疫情的防治提供了科学参考。