2011 Annual Report
1a.Objectives (from AD-416)
The project plan for this CRIS project has four general objectives that are designed to increase our basic understanding of avian influenza virus (AIV) and to develop improved control measures. The specific objectives are listed below.
1. Identify determinants of virulence, tissue tropism and host range of AIV.
2. Develop vaccines that effectively stop outbreaks, allow differentiation from natural infection and can be administered in a cost effective manner.
3. Improve existing diagnostic tests and develop new diagnostic tests that are rapid, sensitive, and improve the detection of avian influenza.
4. Use molecular epidemiologic techniques and viral genomics to understand virus transmission and spread of AI outbreaks in poultry and wild birds.
1b.Approach (from AD-416)
A multidisciplinary approach will be used to study avian influenza virus (AIV) in poultry with particular emphasis on highly pathogenic avian influenza. The use of molecular biological techniques including RT-PCR, cloning, and sequencing will be used for molecular epidemiology, development of an influenza sequence database, and the use of reverse genetics to engineer influenza viruses to examine an individual viral genes role in virulence. For studying the pathogenesis of influenza, gross and clinical pathology, histology, immunohistochemistry, and quantitative RT-PCR will be used to examine the effect of infection with different viral strains and protection in vaccine trials. Cellular biology, immunology, and host genetics will be used to determine the role of host resistance to influenza infection. Improved diagnostic tests, emphasizing rapid detection, will be developed. Continued surveillance of wild bird isolates will continue with collaborators from several different institutions. These efforts should provide better control measures. Dates for latest lab inspection by APHIS: BSL-2 1/29/2008 and BSL-3AG 5/15/2007.
During fiscal year 2011 substantial progress was made for all milestones and progress was made on all objectives of the project. Vaccination is a major control tool for avian influenza virus (AIV), but since the virus mutates so rapidly the virus strains used to make vaccines must be continually updated. Currently there is no universal criteria for when vaccine is no longer effective enough to be used and must be replaced in the field. Work has been conducted to determine whether vaccine efficacy can be correlated to the difference between the immune response to the vaccine and the immune response to the field virus (for example, the more similar the immune responses are the better the vaccine should work). Because AIV vaccination is very expensive because it must be administered by hand to each individual bird another study was completed which showed that a single vaccination could protect ducks and geese from AIV as long as the vaccine is closely related to the field virus, but additional vaccinations will be necessary if the field virus is not related.
Diagnostic tests for AIV can be affected by the rapid mutation of the virus; therefore we developed updated tests for type A influenza to accommodate mutations in recent pandemic strains. These updates will ensure that the tests we have will continue to perform optimally. We have also conducted work to evaluate sample processing methods that will further improve AIV detection in poultry. Sequencing and analysis has also been completed for nearly 1000 AIV genes and new isolates are being continually added to the analysis. Additional work has been completed in characterizing the viral factors of AIV which are responsible for causing disease and death in difference avian species such as chickens and ducks. Host range is a critical factor in virus spread. To address this some projects which evaluate host range had been completed. One study looked at the differences among the H5 subtype of AIV in domestic poultry (chickens, turkeys and ducks), which suggests that turkeys may be more easily infected with AIV. Another study evaluated whether canine influenza or "dog flu" can infect chickens, turkeys and ducks and found that dog flu does not easily transmit directly to domestic poultry.
A single vaccination can protect ducks and geese from avian influenza virus if the virus and vaccine are related. Vaccination for avian influenza is very expensive because each bird must be handled, therefore it is critical to know the minimal numbers of vaccinations that are needed to be protective. ARS researchers in Athens, GA, showed that a single vaccination was protective for ducks and geese against highly pathogenic avian influenza as long as the virus in the field is related to the virus in the vaccine. This information is critical for vaccine programs and manufacturing because it shows that keeping vaccines updated with the most recent strains in the field will save money by reducing the number of times a bird needs to be vaccinated.
Canine influenza does not easily infect poultry. Canine influenza has become common in dogs in the U.S. in the past few years and since influenza has a wide host range it needed to determine if this was a concern for poultry. ARS researchers in Athens, GA, completed a study which showed that canine influenza did not cause disease, nor could it even infect chickens, turkeys or ducks. The impact is that this demonstrated that dogs infected with influenza are unlikely to infect disease in poultry, avoiding the expense and problems with controlling dogs as a potential disease threat for poultry.
There is concern that avian influenza virus and Newcastle disease virus can be transported in liquid egg products. Thermal inactivation studies were conducted with liquid egg product and three strains of avian influenza virus and one strain of Newcastle disease virus to establish the times and temperatures necessary to inactivate the virus. This information will be used to develop pasteurization standards for liquid egg products. Being able to pasteurize egg products which may contain avian influenza virus and Newcastle disease virus will minimize the risk of transporting and using these products which will save substantial money in by mitigating trade losses and having to destroy these products.
Swayne, D.E. 2010. Avian influenza (fowl plague). In: Kahn, C.M., editor. Merck Veterinary Manual. 10th edition. Whitehouse, NJ: Merck and Co., Inc. p. 2498-2500.
Swayne, D.E. 2010. Other avian paramyxovirus infections. In: Kahn, C.M., editor. Merck Veterinary Manual. 10th edition. Whitehouse, NJ: Merck and Co., Inc. p. 2458-2459.
Toro, H., Suarez, D.L., Tang, D.C., Van Ginkel, F.W., Breedlove, C. 2011. Avian influenza mucosal vaccination in chickens with replication-defective recombinant adenovirus vaccine. Avian Diseases. 55:43-47.
Chmielewski, R.A., Swayne, D.E. 2011. Avian influenza: Public health and food safety concerns. Annual Review of Food Science & Technology. 2:37-57.
Slomka, M., Densham, A., Coward, V.J., Essen, S., Brookes, S.M., Irvine, R.M., Spackman, E., Ridgeon, J., Gardner, R., Hanna, A., Suarez, D.L., Brown, I. 2010. Real time reverse transcription (RRT)-polymerase chain reaction (PCR) methods for detection of pandemic (H1N1) 2009 influenza virus and European swine influenza A virus infections in pigs. Influenza and Other Respiratory Viruses. 4:277-293.
Mckinley, E.T., Spackman, E., Pantin Jackwood, M.J. 2010. The pathogenesis of H3N8 canine influenza virus in chickens, turkeys and ducks. Influenza and Other Respiratory Viruses. 4:353-356.
Stittelaar, K.J., Lacombe, V., Van Lavieren, R., Van Amerongen, G., Simon, J., Cozette, V., Swayne, D.E., Poulet, H., Osterhaus, A.D. 2010. Cross-cloade immunity in cats vaccinated with a canarypox-vectored avian influenza vaccine. Vaccine. 28(31):4970-4976.
Kuiken, T., Van Den Brand, J., Van Riel, D., Pantin Jackwood, M.J., Swayne, D.E. 2010. Comparative pathology of select agent influenza A virus infections. Veterinary Pathology. 47(5):893-914.
Pillai, S.P., Pantin Jackwood, M.J., Suarez, D.L., Lee, C. 2010. Pathobiological characterization of low-pathogenicity H5 avian influenza viruses of diverse origins in chickens, ducks and turkeys. Archives of Virology. 115:1439-1451.
Eggert, D.L., Swayne, D.E. 2010. Single vaccination provides limited protection to ducks and geese against H5N1 high pathogenicity avian influenza virus. Avian Diseases. 54:1224-1229.
Chmielewski, R.A., Beck, J.R, Swayne, D.E. 2011. Thermal inactivation of avian influenza virus and Newcastle disease virus in a fat-free egg product. Journal of Food Protection. 74(7):1161-1168.
Wasilenko, J.L., Arafa, A.M., Selim, A.A., Hassan, M.K., Aly, M.M., Ali, A., Nassif, S., Elebiary, E., Balish, A., Klimov, A., Suarez, D.L., Swayne, D.E., Pantin Jackwood, M.J. 2011. Pathogenicity of two Egyptian H5N1 highly pathogenic avian influenza viruses in domestic ducks. Archives of Virology. 156(1):37-51.