Progress 10/01/00 to 09/30/04
Outputs
Objective 1. Determine the pathogenesis and interactions of specific agents. Avian influenza virus-Low path H7N2 AIVs from Delmarva broiler chickens were more pathogenic for broilers and turkeys than for SPF white leghorn chickens and suggest that host species plays an important role in susceptibility to disease. Infectious bronchitis virus and Newcastle disease virus-Q RT-PCR was found to be a suitable procedure for measuring IBV and NDV following coinfection with vaccine strains in chick embryos and chickens. In eggs, IBV replication interfered with the growth of a commercial B1 and highly attenuated CA B1 strain. In chicken, Ca strain NDV replication was greatly diminished by IBV. No effect was observed on IBV growth. Infectious bronchitis virus-Although antigenic differences were observed by VN, S1 sequencing and challenge of immunity findings suggest that Georgia 98 and Alabama isolates AL/2975/00 and AL/3701/00 obtained from the 1999-2000 outbreak were related to
the DE/072/92 strain of IBV. Inactivated IBV vaccination using the autogenous PA/Wolgemuth/98 strain following live virus priming provided better protection than the heterologous Mass + Ark inactivated vaccine vs. PA/Wolgemuth/98 strain challenge. effect of MDV on IBV vaccination. The findings suggest that HVT + SB1 vaccination at 1-day of age is highly effective vs. MDV challenge and virulent MDV challenge in MDV vaccinated chickens does not suppress IBV immunity. Gene expression profiling of avian macrophage activation-Gene expression of avian macrophage activation was conducted using a 4906 element macrophage-specific microarray. Of the elements on AAM, 981 (20%) exhibited significant (>2-fold, p<0.01) changes in expression changes during phagocytosis of Escherichia coli and 243 (5%) exhibited significant expression for both phagocytosis and LPS stimulation, representing a set of core response elements. Mycoplasma-Compared to M. gallisepticum S6, there were varied abilities of
attenuated strains to enter CEF cells suggesting that attenuation may limit the intracellular invasion of CEF cells. Objective 2. Surveillance occurrence and consequences of agents and host variation on disease susceptibility. Infectious bronchitis virus, Newcastle disease virus and avian adenovirus-Viruses other than low path H7N2 avian influenza were recovered from cases of respiratory disease in commercial broilers during surveillance for AIV in 2004 on the Delmarva peninsula. IBV was the most frequently isolate virus from the respiratory tract (52%) followed by NDV (38%), and avian adenovirus (10%). The isolation of IBV, NDV and Adenovirus was more frequent from older broiler flocks (>28 days of age) than from younger (<28 days of age) flocks. Arkansas S1 genotype type IBVs were much more often isolated than were other genotypes (Massachusetts and Connecticut). Objective 3. Develop new and improved methods for the diagnosis, prevention, and control of avian respiratory diseases.
Mycoplasma-
Impacts
No deleterious effects on IBV vaccination responses were observed upon challenge with vv+MDV. However, further research is needed to determine any potential effects of MDV vaccination in ovo in the face of virulent MDV challenge on IBV immunity. Inactivated IBV vaccination using the autogenous strain (PA/Wolgemuth/98) provided better protection than a heterologous combination (Mass + Ark) upon challenge with the a novel virulent nephropathogenic strain Identifying the frequency of IBV and NDV isolations from commercial broiler chickens is important for monitoring pathogenicity of field strains and the effectiveness of vaccination programs. Development and application of tools to assess IBV and NDV replication can be used to determine if interference occurs and could lead to reduced immunity. New, milder NDV strains such as VG and C2 have been introduced to reduce respiratory reactions in broiler chicks. These strains may be more susceptible/sensitive to interfering
effects of IBV replication. Infectious bronchitis in the Southeast United States during the winter of1999-2000 was associated with major economic losses in broiler flocks. Vaccination with commercial vaccines containing combinations of Massachusetts, Connecticut and Arkansas vaccines did not protect flocks. Identifying genes involved in pathogenesis may allow the development of a vaccine that would effectively block M. synoviae infections. Of particular interest would be genes expressing surface proteins involved in attachment to host cells.
Publications
- Gelb, J., Jr., C. L. Keeler, B. S. Ladman and B. F. Kingham. 2002. S1 sequencing and its use in understanding nephropathogenic IBV in Pennsylvania. Proc. Summit V The Challenge of Infectious Bronchitis. Atlanta, Georgia.
- Gelb, J., Jr., B. S. Ladman, C. R. Pope, A.F. Ziegler, T. Swieczkowski and J. M. Callahan. 2002. Inactivated virus vaccination for controlling the nephropathogenic PA/Wolgemuth/98 strain of infectious bronchitis virus. Proc. Western Poultry Disease Conference and ANECA, Puerto Vallarta, Jalisco, Mexico.
- Gelb, J., Jr., B. S. Ladman, P. R. Woolcock, F. J. Hoerr, K. C. Cookson, D. W. Trampel, A. F. Ziegler, and B. D. Binnington. 2002. Presence of a novel S1 infectious bronchitis virus genotype PA/1220/98 in North America; Implications for understanding spread of the virus. Proc. 74th Northeastern Conference on Avian Diseases. Mystic, Connecticut.
- Gelb, J., Jr., B. S. Ladman, P. R. Woolcock, F. J. Hoerr, K. C. Cookson, D. W. Trampel, A. F. Ziegler, and B. D. Binnington. 2002. Recognition of a unique, widely-disseminated infectious bronchitis virus genotype in North America; Implications for understanding spread of the disease. Proc. AVMA/AAAP Annual Meeting. Nashville, Tennessee.
- Whetzel, P. L., L. L. Hnatow, C. L. Keeler, Jr., and J. E. Dohms. 2001. Transposon mutagenesis of Mycoplasma gallisepticum.
- Gelb, J., Jr. 2002 Infectious bronchitis in multi-age layer complexes. Proc. Midwest Poultry Federation Convention. St. Paul Minnesota. pp. 172-178.
- Ladman, B. S., C. R. Pope, A. F. Ziegler, T. Swieczkowski, J. M. Callahan, S. Davison, and J. Gelb, Jr. 2002. Live and inactivated virus vaccination for controlling the nephropathogenic PA/Wolgemuth/98 strain of infectious bronchitis virus. Proc. 74th Northeastern Conference on Avian Diseases. Mystic, Connecticut.
- Ladman, B. S., C. R. Pope, A. F. Ziegler, T. Swieczkowski, J. M. Callahan, S. Davison, and J. Gelb, Jr. 2002. Protection of chickens following live and inactivated virus vaccination against challenge with nephropathogenic infectious bronchitis virus PA/Wolgemuth/98. Avian Dis. 46:938-944.
- Whetzel, P. L., L. L. Hnatow, C. L. Keeler, Jr.,and J. E. Dohms. 2002. Transposon mutagenesis of Mycoplasma gallisepticum. Plasmid.
- Ziegler, A. F., B. S. Ladman, P. A. Dunn, A. Schneider, S. Davison, P. G. Miller, H. Lu, D. Weinstock, M. Salem, R. J. Eckroade, and J. Gelb, Jr. 2002. Nephropathogenic infectious bronchitis in Pennsylvania chickens 1997-2000. Avian Dis. 46:847-858.
- Ladman, B. S., C. R. Pope, A. F. Ziegler, T. Swieczkowski, and J. M. Callahan , and J. Gelb, Jr. 2002. Protection of chickens following live and inactivated virus vaccination against challenge with nephropathogenic infectious bronchitis virus PA/Wolgemuth/98. Avian Dis. 46:938-944.
- Gelb, J., Jr. and B. S. Ladman. 2003. Infectious bronchitis update-Current thinking on controlling IB. Is it working or is it the lull before the next storm? Proc. North Atlantic Poultry Health and Management Conference. Portsmouth, New Hampshire.
- Gelb, J., Jr. 2003. Future challenges and opportunities in poultry disease epidemiological methodology. Proc. Seventy-fifth Ann. Mtg. Northeastern Conference on Avian Diseases. University of Maine, Orono, Maine.
- Campion, L. 2003. Assessment of interference between live infectious bronchitis virus and Newcastle disease virus vaccines using quantitative polymerase chain reaction. Proc. Seventy-fifth Ann. Mtg. Northeastern Conference on Avian Diseases. University of Maine, Orono, Maine.
- Gelb, Jr., J., L. Campion and B. S. Ladman. 2003. Replication interference associated with infectious bronchitis virus and Newcastle disease virus co-infections. Proc. AVMA/AAAP Ann. Mtg. AVMA Convention Notes (Poultry section) compact disc. Denver, Colorado.
- Gelb, J., Jr., J. K. Rosenberger, B. S. Ladman, and S. S. Cloud. 2003. Exotic Newcastle disease-Real world trials at the University of Delaware. Proc. 38th National Meeting on Poultry Health and Processing. Ocean City, Maryland. p. 17.
- Gelb, Jack, Jr. 2004. Respiratory Coronavirus of Chicken: Ongoing Challenges Posed by Infectious Bronchitis Virus. Seventh Annual Conference On Vaccine Research. National Institute for Infectious Diseases. Arlington, Virginia.
- Gelb, Jack, Jr., Sandra S. Cloud, Brian S. Ladman, Mariano Salem, and John K. Rosenberger. 2004. Respiratory disease virus characterization from Delmarva high mortality flocks. Proc. 39th National Meeting on Poultry Health and Processing. Ocean City, Maryland. p. 93. Cloud,S., J. Gelb, C. Pope, J. Rosenberger and B. Ladman. 2004. Characterization of Avian Influenza Viruses Isolated from Delmarva Broilers. Proc. 39th National Meeting on Poultry Health and Processing. Ocean City, Maryland. p. 96.
- Gelb, Jack, Jr., and Mariano Salem. 2004. Avian Influenza in Delmarva. North Atlantic Regional Conference, Northeast District Veterinary Command. Fort Dix, NJ,
- Boettger, C. M. and J. E. Dohms. 2004. Development of Methods to Separate Mycoplasma gallisepticum Field Strains from Non-pathogenic Avian Mycoplasmas. Presented at the 76th Northeastern Conference on Avian Diseases, June 9-11, State College, PA
- Land, J.M., C. M. Boettger, and J.E. Dohms. 2004. Studies of Intracellular Survival Using Wild Type and Attenuated Mycoplasma gallisepticum strains. Presented at the 76th Northeastern Conference on Avian Diseases, June 9-11, State College, PA
- Bliss, T. W., J.E. Dohms, M. G. Emara, and C. L. Keeler. 2004. Gene Expression Profiling of Avian Macrophage Activation. Veterinary Immunology and Immunopathology (in press).
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