The overlap between the East Asian and Pacific America flyway has always been viewed as the most direct route for birds to carry HPAI into North America, but two years ago we looked at the potential of avian flu arriving via the transatlantic route (see PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses).
Six months later, HPAI H5N8 did arrive - almost certainly from Asia - but at the same time, the virus also appeared in Western Europe.
While a less obvious threat than China - as we've seen in France over the past 6 months - new reassortant avian flu viruses can appear anywhere in the world, making the North Atlantic Flyways a potential conduit for novel viruses to reach North America.
In 2014 the USGS reported:
USGS scientists and Icelandic partners found avian flu viruses from North America and Europe in migratory birds in Iceland, demonstrating that the North Atlantic is as significant as the North Pacific in being a melting pot for birds and avian flu. A great number of wild birds from Europe and North America congregate and mix in Iceland's wetlands during migration, where infected birds could transmit avian flu viruses to healthy birds from either location.
By crossing the Atlantic Ocean this way, avian flu viruses from Europe could eventually be transported to the United States. This commingling could also lead to the evolution of new influenza viruses. These findings are critical for proper surveillance and monitoring of flu viruses, including the H5N1 avian influenza that can infect humans.
Although all we have is the abstract, today we've a new study that characterizes avian flu viruses found in Greenland, and like the 2014 study, finds evidence suggesting avian viruses are hitching a ride across the North Atlantic.
Avian Diseases 60(1s):302-310. 2016
First Characterization of Avian Influenza Viruses from Greenland 2014
Christina Marie HartbyA, Jesper Schak KrogA, Flemming MerkelBC, Elisabeth HolmA, Lars Erik LarsenA and Charlotte Kristiane HjulsagerAD
In late February 2014, unusually high numbers of wild thick-billed murres (Uria lomvia) were found dead on the coast of South Greenland. To investigate the cause of death, 45 birds were submitted for laboratory examination in Denmark.
Avian influenza viruses (AIVs) with subtypes H11N2 and low pathogenic H5N1 were detected in some of the birds. Characterization of the viruses by full genome sequencing revealed that all the gene segments belonged to the North American lineage of AIVs.
The seemingly sparse and mixed subtype occurrence of low pathogenic AIVs in these birds, in addition to the emaciated appearance of the birds, suggests that the murre die-off was due to malnutrition as a result of sparse food availability or inclement weather.
Here we present the first characterization of AIVs isolated in Greenland, and our results support the idea that wild birds in Greenland may be involved in the movement of AIV between North America and Europe.