Influenza A viruses circulate among many wild aquatic birds that migrate between wintering grounds in southern latitudes to breeding ranges in the arctic. A new study co-authored by USGS National Wildlife Health Center scientists, hypothesizes that arctic and subarctic zones serve as ecologic drivers of the intercontinental movement and reassortment of IAVs. Iceland is a staging ground that connects Europe’s East Atlantic Flyway and North America’s Atlantic Flyway, providing a unique location for studying viral flow between the eastern and western hemispheres.

Between 2010 and 2018, NWHC scientists conducted fieldwork in Iceland to obtain virus isolates from various species of seabirds, shorebirds, and waterfowl, as well as environmental samples. “Our work in Iceland allowed critical inferences regarding the potential for intercontinental movement of avian influenza viruses,” said Bob Dusek, NWHC Wildlife Biologist and co-author of the study.

The study’s findings demonstrate that Iceland connects virus movement between mainland Europe and North America, consistent with the westward migration of wild birds from mainland Europe to Northeastern Canada and Greenland. These data identify patterns of virus movement in northern latitudes and inform future surveillance strategies related to seasonal and emergent IAVs with potential public health concern.

Recently, Iceland has confirmed HPAI H5N1 in a single white-tailed eagle (Haliaeetus albicilla) found dead October 8, 2021. Genetic sequencing will help determine whether this bird represents a spatial and temporal link between the ongoing outbreak in Europe and introduction of this virus to North America.

According to Dusek, “This recent finding of HPAI in Iceland highlights the value of avian influenza research being conducted by the NWHC and our vast network of partners and helps us understand the intercontinental spread of avian influenza viruses.”