New serotypes of Riemerella anatipestifer isolated from ducks in Thailand

Thirty-two Riemerella anatipestifer isolates from ducks were serotyped by agar gel precepitin test using chicken antisera against serotypes 1 to 19 R. anatipestifer reference strains. The heat stable saline extracts from 29 field isolates reacted with the antisera of serotypes 1, 6, 7, 10, 11, 14, or 19. The isolates belonging to serotype 1 were the most prevalent (56.3%). Antigens from the remaining three isolates did not react with any of the available antisera. Additional investigations showed that they represent two new serotypes, serotypes 20 and 21.     

Infectious bronchitis virus: S1 gene characteristics of vaccines used in China and efficacy of vaccination against heterologous strains from China.

The entire S1 protein genes of eight infectious bronchitis (IB) vaccine strains used in China were compared with those of the IB virus isolates present in the field in China. The nucleotide and amino acid similarities between the eight IB vaccine strains and the field strain, tl/CH/LDT3/03, which was isolated from a teal (Anas sp.), were not more than 81.1% and 79.2%, respectively. Phylogenetic analysis based on the S1 genes showed that the vaccines and field strains belonged to different clusters and showed larger evolutionary distances, and indicated that they were of different genotypes. Four out of the eight vaccines, in addition to the Massachusetts type vaccine H120, were used for protection tests against challenge by the IB virus isolate tl/CH/LDT3/03. This revealed that each of the five IB vaccines induced poor protection against the teal isolate, as assessed by respiratory protection, clinical signs and mortality, indicating the necessity of developing vaccines from local strains for IB control in China.     

Location of the amino acid differences in the S1 spike glycoprotein subunit of closely related serotypes of infectious bronchitis virus

Four UK strains of three different serotypes were found to differ by only 2-3% of their S1 amino acids. The S1 sequences were also very similar to those of three Dutch isolates (D207, D274 and D3896), the greatest difference between two of the seven isolates being 4.4%. The few amino acid differences between the seven isolates were located largely between residues 19-122 and 251-347 of the mature S1 subunit. The seven isolates could be differentiated using 16 monoclonal antibodies in an enzyme-linked immunosorbent assay. Some virus neutralizing (VN) antibody-inducing epitopes were common to all seven isolates even though the strains had been differentiated into three serotypes by polyclonal sera. The results indicate that the most antigenic of the VN antibody-inducing epitopes are formed by very few amino acids and that these occur in the first and third quarters of the S1 subunit. We suggest that serology-based epizootiological studies of IBV should, therefore, be augmented by the inclusion of nucleic acid sequencing and/or monoclonal antibody analysis.     

Genetic diversity of avian infectious bronchitis coronavirus strains isolated in China between 1995 and 2004

Summary. Twenty-six avian infectious bronchitis (IB) viruses (IBV) were isolated from outbreaks in chickens in China between 1995 and 2004. They were characterized by comparison with twenty-six Chinese reference strains and five other IBV strains. Chinese IBVs, which were mainly nephropathogenic, were placed into seven genotypes. Fourteen Chinese IBV isolates were placed in genotype I, having small evolutionary distances from each other. Genotype II included 6 strains that were isolated in the 1990s in China. Genotype III consisted of eight Chinese isolates that showed close relationship with Korean IBV isolates. Another eight IBV isolates clustered in genotype IV and showed larger evolutionary distances. The Massachusetts serotype was present in China in 1990s and was in a separate genotype. Two isolates, HN99 and CK/CH/LHN/00I, which might be a reisolation of vaccine strains, clustered into genotype VI. Four Chinese IBV isolates formed another genotype and showed larger evolutionary distances from other Chinese IBV genotypes (genotype VII). IBVs in same genotypes showed more than 90% amino acid sequence similarities, whereas most of the viruses in different genotypes showed less than 90%. The results showed that IBVs in China came from genetic changes both in IBV populations that existed before the advent of vaccination and in the viruses that were introduced through live vaccines. IBVs showing various genetic differences are cocirculating in China.     

A serological classification of bovine enteroviruses

Summary Cross virus neutralization (VN), complement fixation (CF) and immunoprecipitation (IP) tests were employed to compare the seven currently recognized bovine enterovirus (BEV) serotypes with seven serologically distinct strains previously isolated in Great Britain and two other BEV from the United Kingdom. Based on criteria used to differentiate other human and animal picornavirus serotypes, it was discovered that BEV types 1, 4, 5 and 6 were related to each other and could be included in a single serotype. Types 3 and 7 were found to be identical, and related to serotype 2. All of the other nine BEV were included in either serotype 1 or 2. Not all of the strains in each serotype were identical and antigenic variants were designated as subtypes. Antigenic relationships not revealed by VN were demonstrated in CF and IP tests. Bovine enterovirus strains whose antisera had the broadest intratypic reactivity were suggested as prototypes. The two proposed BEV serotypes could also be distinguished by their ability to agglutinate erythrocytes. Guinea pig erythrocytes were agglutinates by both serotypes while sheep red cells only reacted with serotype 1.     

Studies with a bivalent infectious bronchitis killed virus vaccine

Haemagglutination inhibition and virus neutralisation antibody responses of chickens given different vaccination programmes were compared. This was followed by a further experiment in which variously vaccinated laying hens were challenged at 30 weeks of age with two strains of infectious bronchitis virus of the "variant" Dutch D207 serotype. Chickens were given primary vaccinations to different strains of infectious bronchitis live virus during rearing and then injected at 16 weeks of age with inactivated oil adjuvanted virus vaccines prepared from either M41, GV101 or both viruses combined (bivalent vaccine). Antibody titres to M41 infectious bronchitis virus were high, and to D207 serotype low. in birds given Mass type vaccines only. In birds given an initial 'priming' with Mass type live vaccine and then 'boosted' with bivalent killed vaccine, high haemagglutination inhibition and virus neutralisation antibody levels against both the M41 and D207 serotypes of infectious bronchitis virus were stimulated. In another experiment, the ability of laying hens vaccinated according to this programme, to withstand challenge with two strains of virulent infectious bronchitis virus of the D207 serotype, was tested. Protection of egg production in vaccinated hens was found to be good and in all groups correlated with the individual hen haemagglutination inhibition titre at the time of challenge. The significance of these results with regard to the use of killed virus vaccines in laying hens and to the necessity to develop live virus vaccines from 'variant' strains of infectious bronchitis virus is discussed.     

Relationship between serotypes and genotypes based on the hypervariable region of the S1 gene of infectious bronchitis virus

Summary.  To group infectious bronchitis virus (IBV) isolates, a genetic grouping method based on hypervariable region 1 (HVR 1, nucleotides 168 to 197) was compared with that based on the whole S1 gene. Both methods resulted in the same grouping data. So the grouping method based on HVR 1 could represent the grouping method based on the whole S1 gene. Taiwan isolates could not be placed within the existing groups. In order to test the correlation between genotype and serotype, a one-way neutralization test was used to compare 9 Taiwan isolates selected from different genotypes with Massachusetts (Mass) (H120) and Connecticut (Conn) standard strains. In addition, a two-way cross-neutralization test was performed in embryonated eggs with the β method (constant-virus, diluted-serum) and the reciprocal neutralization titers were calculated to give the relatedness (r) values. The results of two kinds of neutralizing tests showed that the serotypes of 9 isolates were different from Mass or Conn. Based on the r-values, 9 isolates were divided into two serotypes which were correlated with their genotypes. From pathogenicity tests, IBV Taiwan isolates could be divided into high, intermediate, and low pathogenicity according to their pathogenicity indexes. However, no relationship exists between pathotype and genotype. In conclusion, the genetic typing method based on HVR 1 can be used for typing IBV isolates. Accepted August 31, 1999/Received January 25, 1999     

Breadth of protection of the respiratory tract provided by different live-attenuated infectious bronchitis vaccines against challenge with infectious bronchitis viruses of heterologous serotypes

The regime of administering the infectious bronchitis (IB) Ma5 vaccine (Massachusetts serotype) at 1 day old and the heterologous 4/91 vaccine at 2 weeks of age, was shown to be highly effective in protecting the respiratory tract of specified pathogen free chickens. Protection, as measured by assessing ciliary activity of the tracheal epithelium following challenge, was excellent against challenge at 5 weeks of age with IB strains of many serotypes, isolated from disease outbreaks in different parts of the world. This vaccination protocol was more effective than revaccination with a vaccine of the same serotype as the first vaccine. Furthermore, significantly better protection was seen when the Ma5 vaccine was given before, rather than at the same time as or following, the 4/91 vaccine. It is suggested that the use of these two IB vaccines will frequently broaden the protection possible against challenge with IB isolates of many different serotypes, without the need to develop a new IB vaccine to combat each new IB serotype that emerges.     

Different genotypes of nephropathogenic infectious bronchitis viruses co-circulating in chicken population in China

Chicken nephropathogenic infectious bronchitis (IB) was prevalent in the most chicken farms during recent years, although the IB vaccination program has been widely performed in China. To characterize the S1 protein of infectious bronchitis virus (IBV) from China, five representative nephropathogenic IB viruses isolated from chickens in different provinces were genetically and phylogenetically analyzed. The results showed that the length of the S1 genes of the isolates were quite different (1,617, 1,620, 1,623, 1,629, and 1,632 nucleotides, respectively). The homology of the nucleotides and amino acids among the five isolates were 76.7% ∼ 92.1% and 73.9% ∼ 89.5%, respectively, indicating a great variation in S1 genes of the isolates. The variation in S1 genes might affect the antigenicity and pathogenicity of the viruses. Genetically, point mutations, insertions, and deletions in the S1 protein can be observed at many positions, especially at the first 150 amino acids in the N-terminal of the S1 protein. Two motif cleavage sites (R-R-X-R-R/S, H-R-R-R-R/S) were observed in the five sequenced strains. Phylogenetic analysis suggested that they belonged to different lineages. These findings indicated that different genotypes of nephropathogenic IB viruses were co-circulating in the chicken population in China.     

Phylogenetic analysis of infectious bronchitis coronaviruses newly isolated in China,and pathogenicity and evaluation of protection induced by Massachusetts serotype H120 vaccine against QX-like strains

Seventy-eight isolates of avian infectious bronchitis virus (IBV) were obtained from different field outbreaks in China in 2009 and genotyped with 34 reference strains. Four genotypes of IBV and three new isolates were identified by phylogenetic analysis and BLAST searches of the entire S1 gene. The results showed that most IBV strains that have circulated in China in recent years belong to the genotype of QX-like strains, and that they could be grouped further into two clusters, regardless of the level of genetic variation displayed. A study of pathogenicity that used three QX-like strains—ck/CH/LSD/091003, ck/CH/LDL/091022 and ck/CH/LJL/090330—showed that the isolates caused the most severe lesions in the kidneys and were therefore nephropathogenic strains with various levels of virulence in specific pathogen free chickens. A vaccination–challenge test that was performed using the three QX-like strains showed that the commercially available H120 vaccine did not provide sufficient protection against challenge with the QX-like isolates, as demonstrated by comparison of the clinical signs, pathological lesions and virus recovery from the trachea and kidney of unvaccinated–challenged and vaccinated–challenged birds.     

Novel human adenovirus causing nosocomial epidemic keratoconjunctivitis

In 2000, we encountered cases of nosocomial infections with epidemic keratoconjunctivitis (EKC) at a university hospital in Kobe, in the western part of Japan. Two human adenovirus (HAdV) strains, Kobe-H and Kobe-S, were isolated from patients with nosocomial EKC infection. They were untypeable by existing neutralizing antisera; however, the isolate was neutralized with homologous antisera. We then encountered several cases of EKC due to nosocomial infections in eye clinics in different parts of Japan. A total of 80 HAdVs were isolated from patients with EKC at eight different hospitals. The partial hexon gene sequences of the isolates were determined and compared to those of the prototype strains of 51 serotypes. All isolates had identical partial hexon nucleotide sequences. Phylogenetic analysis classified these isolates into species of HAdV-D. The isolates showed 93.9 to 96.7% nucleotide identity with HAdV-D prototype strains, while all 32 HAdV-D prototype strains ranged from 93.2 to 99.2% identity. The sequences of the loop 2 and fiber knob regions from the representative strain, Kobe-H, were dissimilar in all prototype strains of 51 serotypes. We believe that this virus is a novel serotype of HAdV that causes EKC.     

Molecular epidemiology and evolution of avian infectious bronchitis virus in Spain over a fourteen-year period

An in-depth molecular study of infectious bronchitis viruses (IBV) with particular interest in evolutionary aspects of IBV in Spain was carried out in the present study based on the S1 gene molecular characterization of twenty-six Spanish strains isolated over a fourteen-year period. Four genotypes were identified based on S1 gene sequence analyses and phylogenetic studies. A drastic virus population shift was demonstrated along time and the novel Italy 02 serotype was shown to have displaced the previous predominant serotype 4/91 in the field. Detailed analyses of synonymous to non-synonymous ratio of the S1 gene sequences of this new serotype Italy 02 suggested positive selection pressures might have contributed to the successful establishment of Italy 02 serotype in our country. In addition, differences on the fitness abilities of new emergent genotypes were indicated. Furthermore, intergenic sequences (IGs)-like motifs within S1 gene sequences of IBV isolates were suggested to enhance the recombination abilities of certain serotypes.     

Increased level of protection of respiratory tract and kidney by combining different infectious bronchitis virus vaccines against challenge with nephropathogenic Brazilian genotype subcluster 4 strains

Genotyping of seven infectious bronchitis virus (IBV) strains isolated in Brazil showed that all belonged to the common Brazilian genotype and that these strains were closest to the subcluster of strain IBV/Brazil/2007/USP-19. Pathotyping of four selected Brazilian strains showed that they all caused a considerable level of ciliostasis in the trachea but at a somewhat lower level than did M41 and Brazilian strains 50/96, 57/96, 62/96 and 64/96 representing four different serotypes that had been reported earlier. In contrast to the M41 challenge strain, all Brazilian isolates replicated in kidney tissue in a high percentage of non-vaccinated challenged birds, clearly showing that they are nephropathogenic. As for the tracheal protection, the results using Massachusetts (Mass) vaccination against the recent strains seemed to show protection higher on average than for the strains reported earlier. A single or twofold vaccination with a Mass vaccine resulted in a mean tracheal protection level against the four challenge strains of 92% and 90%, respectively, whereas a single and twofold vaccination with a Mass vaccine halved the percentage of infected kidneys (14% and 13%, respectively, P?P?相似文献   

Characterisation of strains of infectious bronchitis virus isolated in Chile

Nine isolates of infectious bronchitis (IB)-like viruses were made from 23 flocks (broilers or layers) in Chile experiencing the types of disease problems commonly associated with IBV. Their identity as IB viruses was confirmed. The histological changes they caused in tracheal organ cultures (OC) are described. Serum neutralisation tests performed in embryonated eggs (alpha-method) suggested that four of the isolates were serologically related to the Massachusetts (Mass) serotype of IBV and one to Connecticut. The four other strains were examined further by a serum neutralisation test in OC (ss-method). One was found to be of the Mass serotype but the others were found to be unrelated antigenically to a wide range of IBV serotypes isolated in many countries over a number of years. One of these three strains and the Mass strain, when given intranasally to 8-day-old specified pathogen free chickens together with pathogenic serotypes of E.coli, caused some mortality and considerable morbidity. The H120 vaccine strain was found not to protect completely against challenge with these four strains 21 days later.     

Evaluation of commercial antisera for serotyping heat-labile antigens of Campylobacter jejuni and Campylobacter coli.

Commercial antisera for serotyping 22 heat-labile antigens of Campylobacter jejuni and Campylobacter coli were evaluated by using 66 isolates from human and nonhuman sources. Test results were compared with results of tests using antisera produced at the Centers for Disease Control (CDC), Atlanta, Ga. All strains (three isolates of each of the 22 serotypes) were typeable with the CDC antisera. Of 66 test strains, 39 (59%) were typed as the same serotype with both sets of antisera. Twenty-four strains (36%), including two heat-labile serotype reference strains, were nonreactive with the commercial antisera, and three strains (4.5%) were typed as serotypes different from those obtained with CDC antisera. Five of the 22 commercial antisera correctly serotyped all homologous strains. Our study indicated that two polyvalent antiserum pools, 7 unabsorbed antisera, and 16 absorbed monovalent antisera are weak and need modification to enhance their antibody titers. Further studies are necessary to explain the antigenic change to a different serotype in three strains.     

Comparison of DNA fingerprinting and serotyping for identification of avian Pasteurella multocida isolates.

The DNA fingerprint profiles and serotypes of 63 avian Pasteurella multocida field isolates, 13 attenuated vaccine isolates (propagated from vaccines manufactured by five companies), and 16 somatic reference strains were compared. DNA fingerprinting established the relationship of isolates that could not be distinguished by serotyping. Of the 76 isolates, 28 DNA fingerprint profiles and 12 somatic types were recognized. One isolate was nonreactive with 16 reference somatic and 5 reference capsule-type antisera. Thirty-one field isolates and seven vaccine isolates were identified as capsule type A. Twenty-nine field isolates and six vaccine isolates were nonencapsulated. Three field isolates were capsule type F. Isolates of capsule types B, D, and E were not found. One field isolate, identified as somatic type 7, had a DNA fingerprint identical to that of the somatic reference type 6 profile. Twelve field isolates had profiles identical to the somatic reference type 3 strain profile; 11 of these were identified as somatic type 3, 4, and 1 was identified as somatic type 3. The DNA fingerprint profiles of 50 field isolates and 13 attenuated vaccine isolates did not match profiles of the 16 somatic type reference strains. Twenty-five DNA fingerprint profiles were recognized from 30 of these field isolates. The DNA fingerprint profiles of 20 field isolates and 13 attenuated vaccine isolates were identical. Three somatic types (3; 3,4; and 4,16) were identified from the field isolates, and two somatic types (3 and 3,4) were identified from the attenuated vaccine isolates. DNA fingerprinting is useful for accurate identification and epidemiologic study of P. multocida isolates.     

Common somatic O and heat-labile serotypes among Campylobacter strains from sporadic infections in the United States.

Somatic O (formerly heat-stable) and heat-labile (HL) serotyping methods are commonly used to type Campylobacter jejuni and Campylobacter coli isolates. Although both systems are effective, the labor and time required for each have limited their application. These systems can be simplified by reducing the number of antisera used. To find an appropriate panel of antisera, we determined the distribution of common serotypes in the United States among a representative sample of 298 Campylobacter isolates. The strains, obtained between July 1989 and June 1990 from persons with sporadic cases of diarrhea, were collected from 19 randomly chosen counties in all geographic (census) regions of the United States. All strains were serotyped by the O and HL systems. By phenotypic methods, 288 C. jejuni, 9 hippurate-negative C. jejuni/C. coli, and 1 Campylobacter lari were identified. Of 57 O antisera, 24 typed 252 (84.6%) strains. Of the 55 HL antisera, 23 serotyped 253 (84.9%) strains. All strains were typeable in the unabsorbed O antisera. In the absorbed HL antisera, four strains were nontypeable and 14 were rough and untypeable. In each geographic region, 9 or more O and HL serotypes were found. Serotypes O:1, O:4, and O:13,16,43,50 and HL 1 were identified in all regions. The combination of both schemes gave greater discrimination than either system alone, but the maintenance of both requires a large resource investment. A serotyping scheme incorporating the 24 most prevalent O and 23 most prevalent HL serotypes could be useful for outbreak support and for surveillance. In the near future, we anticipate using a molecular subtyping method in combination with limited serotyping to distinguish Campylobacter strains.