Avian Influenza, an International Concern

The spread of the virulent highly pathogenic avian influenza virus H5N1 Asian strain (HPAI H5N1) throughout Asia and into Europe and Africa since 2004 has resulted in the loss of millions of domestic birds and caused concern about its zoonotic potential. Though the significance of wild birds in the transmission of HPAI H5N1 remains unclear, wild birds are known to be the source of some outbreaks and can serve as an important sentinel for introduction of the virus to new areas due to expansive migration movements. The comprehensive HPAI H5N1 surveillance program, established in 2006 by the USDA and USDI Fish and Wildlife Service in cooperation with the states and tribes, monitors both wild and domestic bird populations to ensure the earliest detection of HPAI H5N1 incursion into the United States. Montana is a priority state in nationwide surveillance because it borders Canada and is divided by the Pacific and Central Flyways. Montana Fish, Wildlife and Parks, USDA/APHIS/Wildlife Services, and USDI Fish and Wildlife Service have conducted AI surveillance in Montana during the last 4 yrs using multiple sampling strategies to optimize the chance of detecting HPAI H5N1. Surveillance targets specific species spatially distributed across the state and temporally distributed across the sampling period. The primary emphasis on wild populations included systematic transects on populations of high priority for morbidity and mortality, along with opportunistically found dead birds, as well as the collection of swab samples from live and hunter-harvested waterfowl. Whereas low pathogenic avian influenza was found in samples each year as expected, no sample tested positive for HPAI H5N1.