Open in a separate window aAll species are gram-negative rods. Molecular Identification There has been a recent significant improvement in the tools available to aid in the diagnosis of infectious coryza. A PCR test that is specific for H. This test is rapid results are available within 6 h compared with days for conventional techniques and recognizes all H. Over 40 H.
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Open in a separate window aAll species are gram-negative rods. Molecular Identification There has been a recent significant improvement in the tools available to aid in the diagnosis of infectious coryza. A PCR test that is specific for H. This test is rapid results are available within 6 h compared with days for conventional techniques and recognizes all H.
Over 40 H. In particular, the NAD-dependent forms of P. This PCR was developed by a random-cloning method, and there is no knowledge of the role, if any, of the target, which has a size of 0.
When used directly on sinus swabs obtained from artificially infected chickens in pen trials performed in Australia, the HP-2 PCR was equivalent to culture in accuracy but was much more rapid In comparing traditional culture and the HP-2 PCR in China, it has been shown that the PCR outperforms traditional culture when used on routine diagnostic submissions The PCR test and traditional culture were used in parallel to investigate suspected infectious coryza outbreaks on eight commercial farms in China.
The provisional diagnosis of infectious coryza was based on field diagnosis. Live chickens or chicken heads were then shipped from the field to the Beijing laboratory. Sinus swabs were collected and were examined directly by PCR as well as being cultured for H. The HP-2 PCR detected 15 of 39 chickens as positive, with these 15 birds coming from six of eight farms, while culture detected only 8 of the 39 chickens as positive, with these birds coming from only four of the eight farms On the two farms that had chickens that were positive by PCR but negative by culture, the chickens showed typical clinical signs, thereby providing further evidence that the culture results were false-negatives.
The submitted chickens from the two farms that were negative by both culture and PCR did not show typical clinical signs of infectious coryza when received at the central laboratory The problems of poor samples, delayed transport, and low-quality but expensive media mean that culture will have a higher failure rate in developing countries than in developed countries.
In contrast, culture failed to detect H. While PCR technology initially appears complex and expensive, the validation and evaluation work of the HP-2 PCR in China is demonstrating that it can be used and can give significantly better results than traditional culture in developing countries. Serology A range of tests have been described for the detection of antibodies to H.
Despite this range of tests, only HI tests are in widespread use. While a range of HI tests have been described, three main forms of HI tests have been recently recognized: termed simple, extracted, and treated HI tests 8. Full details of how to perform these tests are available elsewhere 8.
In this section, the advantages and disadvantages of the three HI tests are briefly and critically reviewed. Although simple to perform, this HI test can detect antibodies only to serovar A. It has been widely used to detect antibodies in infected as well as vaccinated chickens 5.
This extracted HI test has been validated mainly by using Page serovar C organisms. The test is capable of detecting a serovar-specific antibody response in Page serovar C-vaccinated chickens A major weakness of this assay is that the majority of chickens infected with serovar C remain seronegative The treated HI test is based on hyaluronidase-treated whole bacterial cells of H.
The extracted HI test has not been widely used or evaluated. It has been used to detect antibodies to Page serovars A, B, and C in vaccinated chickens, with only serovar A- and C-vaccinated chickens yielding high titers It has also been used to screen chicken sera in Indonesia for antibodies arising from infection with serovars A and C Vaccinated chickens with titers of or greater in the simple or extracted HI tests are protected against subsequent challenge There is not enough knowledge or experience yet to draw any sound conclusions on whether there is a correlation between titer and protection for the treated HI test.
A recently described serological test is a monoclonal antibody-based blocking enzyme-linked immunosorbent assay ELISA While having shown very good specificity and acceptable levels of sensitivity, this test has several drawbacks. Since there are only monoclonal antibodies for Page serovars A and C, the assay can detect antibodies only to these two serovars. The monoclonal antibodies that form the heart of the assays are not commercially available, limiting access to the assays.
Finally, some isolates of H. As well, isolates of Kume serovar C-4, which has been found only in Australia and consists of just 13 isolates 4 , do not react with the serovar C monoclonal antibody. The reduced sensitivity of the ELISA for serovar C infections indicates that the test would have to be used as a flock test only Overall, the serological test of choice for coryza varies with the serovar and the intended use, i.
The simple HI test 21 is suitable for either infections or vaccinations associated with serovar A, the extracted or treated HI tests 31 , 41 are suitable for vaccinations associated with serovar C, and the treated HI test 41 is suitable for infections associated with serovar C. There has been so little work performed on serological assays for infections or vaccinations associated with serovar B that it is not possible to recommend any test. The limitations outlined above for the HI tests mean that there is still a need for robust, well-characterized serological assays.
The monoclonal antibody-based ELISAs have shown the potential of this format to diagnose infectious coryza, and future research on this type of approach, including the development of new panels of monoclonal antibodies, particularly to Page serovar B, may help overcome some of the problems of the current ELISAs. Vaccines Commercial vaccines for infectious coryza, typically based on killed H. An extensive review of the literature on inactivated infectious coryza vaccines has been recently published 2.
For this reason, only two aspects of infectious coryza vaccines are covered in this review. Until recently, most of these vaccines contained only Page serovars A and C.
This concept of a bivalent vaccine was based on the belief that Page serovar B was not a true serovar and that serovar A and C based vaccines provided cross-protection.
However, because it has now been conclusively shown that Page serovar B is distinct, commercial trivalent vaccines are now available from the major international vaccine companies The major global vaccine companies tend to base their vaccines on standard, internationally recognized strains.
These international vaccines are sold around the world on the basis that local variation is not sufficient to justify adding or removing strains. Recently, a number of research groups, including Bragg et al. CONCLUSIONS This review has covered literature evidence stressing that infectious coryza, while often seen as a simple, mild upper respiratory disease of chickens in developed countries, can be a much more complicated disease in developing countries.
There have been significant increases in our ability to accurately diagnose infectious coryza, particularly the validation of the HP-2 PCR. There is a need for definitive work to investigate the role of the NAD-independent forms of H. The wonderful skills of the scientists and technicians who have worked in the Bacteriology Research Laboratory have been the basis of all our work on infectious coryza.
Molecular epidemiology of Ornithobacterium rhinotracheale. J Clin Microbiol. Blackall P J. Vaccines against infectious coryza. Serotyping of Haemophilus paragallinarum by the Page scheme: comparison of the use of agglutination and hemagglutination-inhibition tests. Avian Dis. Proposal of a new serovar and altered nomenclature for Haemophilus paragallinarum in the Kume hemagglutinin scheme.
Infectious coryza. Diseases of poultry. Ames: Iowa State University Press; Characterization of isolates of avian haemophili from Brazil. Evaluation of two monoclonal antibodies for serotyping Haemophilus paragallinarum. Blackall P J, Yamamoto R. In: Swayne D E, editor. A laboratory manual for the isolation and identification of avian pathogens. Evaluation of a panel of monoclonal antibodies in the subtyping of Haemophilus paragallinarum. An assessment of the genetic diversity of Australian and overseas isolates of Haemophilus paragallinarum by multilocus enzyme electrophoresis; p.
Changes in the incidences of the different serovars of Haemophilus paragallinarum in South Africa: a possible explanation for vaccination failures. Onderstepoort J Vet Res. Isolation and identification of NAD-independent bacteria from chickens with symptoms of infectious coryza. Avian Pathol. Further studies on the use of a polymerase chain reaction test for the diagnosis of infectious coryza.
Ornithobacterium rhinotracheale infection in turkey breeders. Infectious coryza in meat chickens in the San Joaquin Valley of California.
Hinz K-H, Kunjara C. Haemophilus avium, a new species from chickens. Int J Syst Bacteriol. Case report. Infectious coryza in broiler chickens in Alabama. Proceedings of the 43rd Western Poultry Disease Conference. NAD V-factor -independent and typical Haemophilus paragallinarum infection in commercial chickens: a five year field study.
Serologic response to Haemophilus gallinarum in artificially infected and vaccinated chickens. Efficacy of a trivalent Haemophilus paragallinarum vaccine compared to bivalent vaccines. Vet Microbiol. Serological classification of Haemophilus paragallinarum with a hemagglutinin system. Pasteurella avium Hinz and Kunjara comb. Isolation and identification of Ornithobacterium rhinotracheale from commercial broiler flocks on the Delmarva peninsula.
Page L A. Haemophilus infections in chickens.
Infectious Coryza: Overview of the Disease and New Diagnostic Options
Infiltration of a large number of most cells into the lamina propria of the mucous membrane of the nasal cavity is also characteristic. Numerous organisms are found on the cilia or on the surface of the epithelial cells of the nasal mucosa. Chickens with the lesions often have severe coryza. Adherence to and colonization of the encapsulated variant on the nasal mucosa seems to be a first step of infection Sawata et al. Colonization of the nasal mucosa by encapsulated A. Acute uncomplicated coryza is characterized by a short duration, with signs usually clinically visible for days, and subsequently results in birds being refractory to reinfection.
Int J Syst Evol Microbiol. Reclassification of Pasteurella gallinarum, [Haemophilus] paragallinarum, Pasteurella avium and Pasteurella volantium as Avibacterium gallinarum gen. This paper describes a phenotypic and genotypic investigation of the taxonomy of [Haemophilus] paragallinarum, Pasteurella gallinarum, Pasteurella avium and Pasteurella volantium, a major subcluster within the avian 16S rRNA cluster 18 of the family Pasteurellaceae. An extended phenotypic characterization was performed of the type strain of [Haemophilus] paragallinarum, which is NAD-dependent, and eight NAD-independent strains of [Haemophilus] paragallinarum. These five sequences along with existing 16S rRNA gene sequences for 11 other taxa within avian 16S rRNA cluster 18 as well as seven other taxa from the Pasteurellaceae were subjected to phylogenetic analysis. The analysis demonstrated that [Haemophilus] paragallinarum, Pasteurella gallinarum, Pasteurella avium and Pasteurella volantium formed a monophyletic group with a minimum of This group can also be separated by phenotypic testing from all other recognized and named taxa within the Pasteurellaceae.