Surveillance for Avian Influenza in the United States BOB H. BOKMA, a CHERYL HALL, a LYNNE M. SIEGFRIED, a AND J. TODD WEAVER b a United States Department of Agriculture, Animal and Plant Health Inspection Service, , Riverdale, Maryland 20737, USA b Centers for Epidemiology and Animal Health, National Center for Animal Health Surveillance, National Surveillance Unit, Fort Collins, Colorado 80526, USA ABSTRACT: In the United States, some 1.7 million agar gel immuno diffusion (AGID) tests for avian influenza (AI) are conducted yearly by various poultry groups, governmental sectors, and private industry. In addition to the AGID test, additional testing includes virus isolations, enzyme-linked immunosorbent assays, real-time reverse transcriptase polymerase chain reactions, and hemagglutination inhibition (HI) tests. HI and neuraminidase inhibition tests are conducted on positive AGID samples to determine the subtype. Directigen, a type of antigen capture test, is used in the field in some cases. If monitoring and surveillance activities give rise to a suspicious test result, the accredited veterinarian and official State laboratory are required to report these to the gov- ernmental authorities. A thorough investigation in collaboration with the National Veterinary Services Laboratories (a World Organization for Animal Health—AI reference laboratory), State and Federal veteri- narians, and others is conducted. Testing conducted as part of the Na- tional Poultry Improvement Plan (NPIP) effectively monitors the status of breeder and multiplier flocks. A new commercial poultry program is being added and will expand NPIP AI testing to all commercial flocks. Private poultry companies conduct additional tests; and in the poultry- producing States, there are active state-wide programs to monitor poul- try health. All components of the live-bird market system (source flocks, haulers, dealers, and markets) are tested under the Low Pathogenicity AI Live-Bird Market Program. KEYWORDS: avian influenza; AGID test; surveillance; live-bird market; biosecurity; HI; NPIP Address for correspondence: Cheryl Hall, United States Department of Agriculture, Animal and Plant Health Inspection Service, National Center for Import and Export, 4700 River Road, Unit 38, Riverdale, MD 20737. Voice: 301-734-4356; fax: 301-734-3222. e-mail: Cheryl.I.Hall@aphis.usda.gov Ann. N.Y. Acad. Sci. 1081: 163–168 (2006). C  2006 New York Academy of Sciences. doi: 10.1196/annals.1373.018 163