The prevention and control of avian influenza: The avian influenza coordinated agriculture project1 C. Cardona,* R. Slemons,† and D. Perez‡2 *Department of Population Health and Reproduction, Veterinary Medicine Extension, University of California, Davis 95616; †Department of Veterinary Preventive Medicine, The Ohio State University, Columbus 43210; and ‡Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park 20742 and control avian influenza. To this end, AICAP has been remarkably successful in generating research data, publications through an extensive network of university- and agency-based researchers, and extending findings to stakeholders. An overview of the highlights of AICAP research is presented.
Key words: avian influenza, poultry, United States Department of Agriculture-Cooperative State Research, Education, and Extension Service, Avian Influenza Coordinated Agriculture Project 2009 Poultry Science 88:837–841 doi:10.3382/ps.2008-00332
INTRODUCTION
Surveillance Efforts
The long-term goal of the USDA-Cooperative State Research, Education, and Extension Service National Research Initiative-funded program entitled “Prevention and Control of Avian Influenza in the US” (Avian Influenza Coordinated Agriculture Project, AICAP) is to serve as a significant point of reference for the poultry industry and the general public in matters related to the biology, risks associated with, and the methods used to prevent and control avian influenza (AI; Perez and Slemons, 2006). This integrated project, which includes projects addressing viral pathogenesis in domestic poultry species, the development of diagnostic tests and vaccines, especially those technologies that support differentiation of infectious from vaccinated animal (DIVA) strategies, surveillance, and outreach to stakeholder groups was initially funded through a competitive process in 2004. Since 2004, the AICAP team, comprised of funded investigators, the scientific advisory board, the stakeholder advisory board, and the co-principal investigators, has created a collective network research structure that establishes the basis for a better understanding of AI (Perez, 2006).
Type A influenza virus surveillance of wild migratory birds is a critical component of the AICAP project. The AICAP research team, led by R. Slemons of The Ohio State University, recognizes the need to detect and characterize the AI virus (AIV) of free-flying birds both as part of a national early warning system (NBII, 2007) and also to better understand how and when AIV are introduced into commercial and noncommercial poultry flocks. From 2005 to 2007, the AICAP network has tested samples from more than 23,000 free-flying birds (Figure 1) in every flyway in the United States (Slemons et al., 2006). Birds in the Atlantic flyway are sampled by J. Gelb at the University of Delaware (Newark) and R. Slemons (The Ohio State University) and C. Driscoll (Maryland Department of Natural Resources, Annapolis), who monitor the Eastern Shore of Maryland (Evers et al., 2007; Runstadler et al. 2007). Birds, primarily waterfowl, in the Mississippi flyway are monitored by the team of J. Giambrone at Auburn University (Auburn, AL; Dormitorio et al., 2007), whereas R. Slemons at Ohio State University maintains study sites in Ohio (Evers et al., 2007; Runstadler et al., 2007). At the University of Minnesota, D. Halvorson coordinates surveillance activities in North Central and Northwestern Minnesota, and R. Foster from the Missouri Department of Agriculture (Jefferson City) and D. Graber of the Missouri Department of Conservation (Jefferson City) coordinate activities at study sites in Southeastern and West Central Missouri. At Texas A&M University (College Station), B. Lupiani sampled
©2009 Poultry Science Association Inc. Received August 7, 2008. Accepted August 14, 2008. 1 Presented as part of the Poultry Science Association Keynote Symposium, “Avian Influenza: Vectors, Vaccines, Public Health, and Product Marketability,” July 20, 2008, at the Poultry Science Association meeting, Niagara Falls, Ontario, Canada. 2 Corresponding author:
[email protected]
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ABSTRACT The Avian Influenza Coordinated Agriculture Project (AICAP) entitled “Prevention and Control of Avian Influenza in the US” strives to be a significant point of reference for the poultry industry and the general public in matters related to the biology, risks associated with, and the methods used to prevent
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birds at the southern end of the Central flyway (Ferro et al., 2008). George Happ at the University of Alaska Fairbanks (Runstadler et al., 2007; Dugan et al., 2008; Wang et al., 2008) and C. Cardona at the University of California, Davis (Siembieda et al., 2008) maintain sampling sites in the Pacific flyway. The AICAP surveillance sites are shown in Figure 2. Although the US Interagency Strategic Plan for Avian Influenza surveillance has focused on the used of
real-time reverse transcription PCR (RRT-PCR) as the method of choice for the testing of wild bird samples (Spackman et al., 2003; NBII, 2007), the AICAP surveillance efforts have largely selected to use a combination of virus isolation and RRT-PCR rather than RRT-PCR alone for virus detection and identification. More recently, it has been recognized that RRT-PCR assays optimized for use in domesticated birds may not be as effective in wild birds as they are in poultry (Das et al., 2007; Runstadler et al., 2007). Further, this early decision about screening methods resulted in the recognition that the method used for identifying H7 viruses (Spackman et al., 2002) from free-flying birds was not detecting viruses of that subtype (Xing et al., 2008) as well as the isolation of more than 600 AIV strains, which can be further characterized (Figure 1).
Diagnostic Test Development
Figure 2. The number of samples from free-flying birds cumulatively tested by the Avian Influenza Coordinated Agriculture Project network of investigators and the percentage of samples yielding a virus isolate. *Complete isolation data not available for 2007.
Diagnostic test development is an evolving need for AI prevention and control. The diversity of AIV and their continuing evolution means that testing methods have to be linked to ongoing surveillance activities both to identify changes in the viruses but also changes in host range that can affect test efficacy. The current
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Figure 1. Avian Influenza Coordinated Agriculture Project wild bird surveillance sites. Sites are indicated by a cross. The approximate locations of the 4 North American flyways are indicated by dotted lines.
KEYNOTE SYMPOSIUM
approach from conventional vaccines with a modified live vaccine (Song et al., 2007).
Exploring the Pathogenesis of AI Perez’s group at the University of Maryland has focused on the transmission of AIV between poultry species. The group has focused on the adaptation of duck origin viruses to land-based poultry species. The results of a study with an H2N2 isolated from mallard ducks indicated that quail could provide an environment in which AIV from wild birds can adapt and increase their host range (Sorrell and Perez, 2007). The AICAP investigators have not only studied AIV adaptation to new hosts in controlled settings, they have also studied transmission of low pathogenic AIV (LPAIV) in live bird market (LBM) settings (Yee et al., 2007, 2008). Additionally, the research team at the University of California, Davis developed a LBM model setting in which they could study transmission among the species that typically populate LBM in Southern California in a controlled setting. They determined that H6N2 LPAIV was not transmitted through handling practices in LBM but rather by airborne droplets (Yee et al., 2007). The AICAP research has not only focused on the exploration of AIV in their reservoir hosts and nontarget hosts like domesticated poultry, it has also addressed the fate of virus in the environment. Eric Benson’s team at the University of Delaware has examined disinfectants and the processes by which they are applied to assess their efficacy against LPAIV. In one study, the group was able to demonstrate that 4 of the 6 disinfectant chemicals tested effectively inactivated LPAIV on hard and nonporous surfaces (Lombardi et al., 2008). This group has used what they found in their initial studies to develop strategies to disinfect equipment, which is both a routine problem for poultry farms and a quandary encountered after a disease outbreak (Benson et al., 2008). Finally, using Newcastle disease virus as a surrogate for AIV, this group explored the fate of virus in the composting carcasses of poultry flocks killed with foam (Benson et al., 2008).
New Approaches to Vaccination
Outreach to Stakeholders
The goal of AICAP investigators was to develop alternative vaccine strategies that would be more effective than current approaches and have the potential to be applied to flocks en masse. In this regard, 2 groups within the AICAP were successful in developing live recombinant vaccines that show great promise as vaccines for mass immunization. Haroldo Toro continues to lead a highly productive research team supported by AICAP in the development of an adenovirus vector recombinant vaccine for in ovo delivery to poultry (Toro et al., 2007, 2008). The research group of Perez has similarly created a vaccine that can be mass applied in poultry flocks and that provides a distinctly alternate
The delivery of research findings to stakeholders is a critical component of AICAP. In the first iteration of AICAP, 2 funded projects led the outreach efforts. In the first of these, E. Benson, R. Alphin, and G. Malone at the University of Delaware, in close collaboration with N. Tablante at the University of Maryland, developed a comprehensive classroom training program in 2005 on mass depopulation and disposal for commercial poultry flocks. Content of the training material included the following: current status of AI worldwide; human health guidelines for responders to an AI outbreak; requirements, options, and procedures for mass depopulation; and disposal options, procedures, and
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H5N1 highly pathogenic AI outbreak has brought to light additional diagnostic challenges such as the need to have testing methods that can be used in remote locations. One development by AICAP investigators V. Vakharia at the University of Maryland Biotechnology Institute (College Park) and D. R. Perez at the University of Maryland, College Park, in cooperation with C. Lamichhane at Synbiotics Corp. (Kansas City, MO), is a rapid antigen capture test, Flu Detect, which can be performed penside. Similar to a simple pregnancy test, this easy-to-use kit has been selected by the Food and Agriculture Organization for use in their multinational initiative to monitor and control the spread of infectious AIV (http://www.worldpoultry.net/news/id220511642/flu_detect_selected_by_fao.html). The antigen capture test and a complementary antibody ELISA detection kit (ProFlok AIV ELISA kit, Synbiotics Co., Kansas City, MO) have received USDA approval and have attracted an important portion of the international market. Calvin Keeler, at the University of Delaware, has developed a cDNA microarray that can address the needs for rapid subtyping of viruses and is a technology that can be updated in response to changes in AIV. Keeler has already met a major objective: the ability of 1 labeling reaction and 1 slide to identify both hemagglutinin and neuraminidase subtypes. These arrays can be designed in minutes and manufactured in less than 2 h, resulting in the ability to perform truly iterative experiments in a single day (Maughan et al., 2006). The need to develop DIVA testing methods has been critical to the poultry industry. Without the development and validation of DIVA diagnostic tests, vaccination is a far less useful tool in prevention. Under AICAP1, M. Garcia led a research team at the University of Georgia (Athens) in the development of DIVA diagnostic testing methods. So far, this group has developed and reported on an N1-specific ELISA (García et al., 2007) and the development of N2-specific reagents and their application in an ELISA (García et al., 2006). With AICAP2 funding, Garcia is working toward the validation of those tests.
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cost with comprehensive details for in-house windrow composting. A total of 33 half-day sessions were held in 26 different states with approximately 1,800 people in attendance (training sites are shown in Figure 1). Additional training sessions were requested by the Canadian poultry industry requested, which supported 5 sessions in 4 provinces, and a condensed version of this material was also taught at 2 locations in Brazil, with the support of the Brazilian government. Eva Wallner-Pendleton from Penn State University (University Park) used her extensive experience with upland gamebirds and her contacts in the industry to develop a 1-d health seminar including wet laboratory training in blood collection and necropsy. Wallner-Pendleton traveled extensively and collaborated with local extension veterinarians and other AICAP investigators to deliver training on upland gamebird health and husbandry to gamebird producers and hunt club owners. With the assistance of the North American Gamebird Association (Eureka, KS), this program reached more than 1,250 people in Kansas, South Dakota, Minnesota, Washington, Alabama, South Carolina, Connecticut, Pennsylvania, Tennessee, Texas, Florida, and California (see Figure 3 for training locations).
Outreach in AICAP2 has taken a different direction, because the funded projects have different users and stakeholders than the previously funded groups. Outreach efforts for AICAP2 are currently focused on the delivery of information about new discoveries from funded research projects through a newly initiated newsletter (Perez, 2007) and a highly informative Web site (Perez, 2006). Additionally, AICAP2 outreach efforts have focused on developing a model to capture the effect of education and outreach efforts. This model will help us in developing and implementing outreach that effectively reaches our target audiences and achieves the specific goals of the program such as the delivery of information all the way to motivating behavioral change.
CONCLUSIONS The AICAP portfolio of surveillance, research, and outreach projects is unique in that it is focused on the prevention of AI in poultry flocks. To that end, the AICAP team of investigators has been highly productive, as we have highlighted here. The newly funded projects of AICAP2 address the research and outreach
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Figure 3. Locations of outreach programs funded by the Avian Influenza Coordinated Agriculture Project. Euthanasia and composting program sites are indicated with a gray circle. Gamebird health seminar locations are indicated with a black star.
KEYNOTE SYMPOSIUM
needs of today and thus are slightly different than what was addressed with the projects funded in AICAP1. With the help and guidance of our stakeholder and scientific advisory boards, AICAP adjusts to address the ever-evolving challenges of AI.
ACKNOWLEDGMENTS
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The studies summarized in this review were supported by AICAP, USDA-Cooperative State Research, Education, and Extension Service grant 2005-3560515388, “The Prevention and Control of Avian Influenza in the US.” We gratefully acknowledge the generous donations of time and expertise given by our scientific review board without which AICAP would not be possible. We also thank Peter Johnson (USDA-Cooperative State Research, Education, and Extension Service) for his unending wisdom, guidance, and support for AICAP and its network of investigators.
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