(Wild geese in Stillwater. Picture by Rachel Higgins)
Outbreaks of various H5 avian influenza strains have occurred in France, Nigeria, Vietnam and Bangladesh. H5 strains, particularly H5N1, are dangerous, as they can spread to pigs, mutate and then pass to humans. Some strains can pass directly to humans and can be lethal for adults.
On Feb. 4, an outbreak of the H5N1 strain of avian influenza in crows was confirmed in Bangladesh and is believed to have spread from France. Although H5N1 is not the main strain in France currently, the country has been dealing with H5N2 since Jan. 28 and has lost thousands of birds.
In addition, Nigeria and Vietnam have both had recent outbreaks of H5 strains with the H5N6 strain in Vietnam concerning health officials. H5N6 is a strain that is also found in Laos, Hong Kong and China that can spread to people, although so far only China has reported human infection. Both Nigeria and Vietnam have lost thousands of poultry and are expected to lose more due to poor biosecurity.
Although the United States has not had an outbreak of H5 strains in recent years, it seems likely that it may spread to North America. Bird flu from Europe seems to be moving into Africa now, and the Asian strains are starting to appear in more countries. The most likely way for an H5 strain to come to North America is the migration route that passes through Alaska and then the Midwest.
Ducks and Canadian geese that fly along this path often carry various strains of avian influenza and are the main source of the virus in recent years. They can contaminate water sources with their feces, which indirectly infects poultry. Currently, only good biosecurity practice can prevent them from spreading the virus.