Guidelines on Wild Bird Surveillance for Highly Pathogenic Avian Influenza H5N1 Virus

The recent spread of highly pathogenic avian influenza (HPAI) H5N1 from Southeast Asia into Europe and Africa emphasizes the need to better understand the mechanisms by which the disease is spread. Current wildlife surveillance has been limited to a combination of targeted sampling, opportunistic sampling, and recovery of dead wildlife. Recent interest in avian influenzas provides an opportunity to develop a global surveillance program for diseases in wild birds. This program should be based on specific principles with clearly defined aims, sound epidemiological sampling justifications, and sufficient technical skills and capabilities for appropriate field and laboratory activities. At present, although detection of H5N1 in healthy wild birds is sporadic, surveillance programs should be focused on: 1) determining the role wildlife plays in the epidemiology of HPAI H5N1 virus, and 2) guiding strategies to prevent disease exposure to humans and poultry. Surveillance should incorporate active and passive components using available natural history information such as intraor interspecies mingling, population size, migratory patterns, and seasonal large-scale aggregations. Passive surveillance can include samples from bird banders/ringers, other wild bird research efforts, oil-spill response efforts, rehabilitation centers, zoological collections, beached-bird surveys, and mortality events. A valuable wildlife surveillance program based on ecological and epidemiological information will require large-scale collaboration among national governments and ministries, multilateral agencies, nongovernment organizations, academicians, veterinarians, virologists, ornithologists, and many others.