Progress 10/01/01 to 09/30/04
Outputs
Examining virus isolation data over time is important for understanding evolutionary trends in IBV and in coronaviruses in general. At the Poultry Diagnostic and Research Laboratory (PDRC, University of Georgia, Athens, GA) we receive clinical samples for IBV typing from all over the world. Herein, we summarize the number, origin and type of IBV isolates identified at PDRC between 1994 and 2004. In general each year shows a biannual distribution pattern of virus isolations (Figure 1) with the most isolations occurring during the summer months (May, June and July), followed by the winter months (December, January, and February). It is interesting that most IBV isolates are made during the summer when many companies cut back on bronchitis vaccination. Examining the origin of IBV types shows that some viruses tend to be geographically restricted to a given area. The CAV isolate has only been isolated in California. Likewise the 97-8147 isolate has only been isolated in
Mexico. No foreign virus types have been detected in the U.S. Finally, it is interesting to note that some highly characterized serotypes of IBV were not isolated during the 11-year period. Those types include FL, Gray, Holt, Iowa, and JMK.
Impacts
Control of IBV could potentially save the commercial poultry industry millions of dollars in lost production due to the disease. To control IBV we must first identify which viruses are causing disease in the field. Identification of IBV types is an ongoing process because the virus continues to change, and is the first step in a successful vaccine control program.
Publications
- Jackwood, M. W., D. A. Hilt, T. Boynton, and S. A. Callison. Molecular analysis of TCoV, SARS-CoV, and IBV: how are they related. p. 158-165, Proceedings of the 4th International Symposium on Avian Corona- and Pneumovirus Infections, Rauischholzhausen, Germany. June 20-23, 2004.
- Callison, S. A., D. A. Hilt, and M. W. Jackwood. Rapid differentiation of avian infectious bronchitis virus isolates by sample to residual ration quantitation using real-time reverse transcriptase-polymerase chain reaction. J. Virol. Meth. 124:183-190. 2005.
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Progress 01/01/03 to 12/31/03
Outputs
Our ongong testing to type IBV field viruses has for the most part resulted in typical viruses that have been previously characterized, and for which commercial vaccines exits. We have identified one variant virus which was newly recognized in 1995 and seems to have resurfaced.In addition, we identified several new viruses that are closely related to the Arkansas type viruses. The significance of those isolates are not yet known. But, we are continuing to monitor the heterogeneity of those viruses and in general, the population of IBV isolates circulating in the field.
Impacts
Control of IBV could potentially save the commercial poultry industry millions of dollars in lost production due to the disease. To control IBV we must first identify which viruses are causing disease in the field. Identification of IBV types is an ongoing process because the virus continues to change, and is the first step in a successful vaccine control program.
Publications
- Jackwood, M.W., Hilt, D.A., and Brown, T.P. Attenuation, safety and efficacy of an infectious bronchitis virus GA98 serotype vaccine. Avian Dis. 47:122-127. 2003.
- Kapczynski, D. R., D. A. Hilt, D. Shapiro, H. S. Sellers, and M. W. Jackwood. Protection of chickens from infectious bronchitis by in ovo and intramuscular vaccination with a DNA vaccine expressing the S1 glycoprotein. Avian Dis. 47:272-285, 2003.
- Jackwood, M.W., Hilt, D.A., and Callison, S.A. Detection of Infectious Bronchitis Virus by Real-Time Reverse Transcriptase-Polymerase Chain Reaction and Identification of a Quasispecies in the Beaudette Strain. Avian Dis. 47:128-134. 2003.
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Progress 01/01/01 to 12/31/01
Outputs
The main objective of this proposal is to control infectious bronchitis (IB). We propose to do this by continuing to study IBV isolates from the field and by developing and testing recombinant vaccines against infectious bronchitis virus (IBV). The specific objectives are: 1. To study the molecular and serologic characteristics of new IBV isolates identified by our reverse transcriptase-polymerase chain reaction/restriction fragment length polymorphism (RT-PCR/RFLP) serotype identification test. 2. To develop and test an IBV virus-like particle (VLP) for its utility as a vaccine against IBV. Objective 1 is ongoing. Currently we are evaluating an IBV isolate designated 95-7728. That virus is highly pathogenic, but appears to be similar to Arkansas. For VPL production, the spike and envelope genes were subcloned into the pIRES vector which allows expression of the two genes simultaneously in cell culture. Expression of spike was verified but rabbit antisera, against the
Beaudette envelope protein, was thus far unreactive.
Impacts
We hope to better control IBV by continually monotering new IBV types and by production of immunogenic recombinant vaccines.
Publications
- Jackwood, M. W., Hilt, D.A., Callison, S.A., Lee, C-W, Plaza, H., and Wade E.D. Spike Glycoprotein Cleavage Recognition Site Analysis of Infectious Bronchitis Virus. Avian Dis. 45:366-372, 2001
- Lee, C-W., Hilt, D.A., and Jackwood, M.W. Identification and Analysis of the Georgia 98 Serotype, a New Serotype of Infectious Bronchitis Virus. Avian Dis. 45:164-172, 2001.
- Callison, S.A., Jackwood, M.W., and Hilt D.A. Molecular Characterization of Infectious Bronchitis Virus Isolates Foreign to the United States and Comparison with United States Isolates. Avian Dis. 45:492-499, 2001.
- Lee, C.W. and Jackwood, M.W. Spike Gene Analysis of the DE072 Strain of Infectious Bronchitis Virus: Origin and Evolution. Virus Genes 22:1, 85-91. 2001.
- Lee, C.W. and M. W. Jackwood. Origin and evolution of Georgia 98 (GA98) a new serotype of avian infectious bronchitis virus. Virus Research 80:33-39, 2001
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