In the past week one of the more virulent forms of Avian Flu has jumped from three to six southern-western Ontario commercial poultry farms. The H5N1 strain has been present on east coast Canadian and American farms over the winter months, but the first Ontario cases were just detected in late March.
Back in December, Avian Influenza was initially found in Newfoundland’s wild bird population and then in a back yard poultry flock. In January there were reports of bird flu in North and South Carolina. Then in February several cases were found in Nova Scotia.
Canadian wildlife officials are not surprised to see the disease spreading. Migratory birds, especially waterfowl, are known to be a primary Avian Flu initial-vector. And, increasingly, some migratory birds are overwintering in both the southern Canadian and north-eastern US latitudes.
Dr. Brian Stevens is an epidemiologist with the Canadian Wildlife Health Co-operative based in Guelph, Ontario. Dr. Stevens says wildlife researchers have been expecting the Avian virus to hit Ontario for the last couple of months. Much of Ontario is in the major Atlantic Flyway zone. Southwestern Ontario is, effectively, a peninsula within the lower Great Lakes basin, and so a primary destination for migratory waterfowl,
“It shouldn’t be a big surprise that we’re now starting to see cases of this in Ontario. Most of the cases of this virus have been reported in the Atlantic Flyway. We’ve seen the virus, so far, mostly along the east coast. North and South Carolina were one of the earliest places that we picked up this virus in our wild populations, but it’s starting to move inland. A lot of these ducks were moving between Ontario and the Carolina’s during their normal migration routes.”
In Europe the Avian Flu virus has been found in some of the smaller wild birds. But Dr. Stevens says that in North America it’s the larger wild bird species that tend to be the more prevalent virus carriers. Waterfowl like ducks and geese usually top the list, but other, larger birds can also be an initial vector.
“The species that are most susceptible to this virus are the water birds. The waterfowl such as our ducks and geese as well as shore-birds like our gulls. And then we have heard of cases in Canada Geese. Raptors appear to be quite susceptible, so Red-tailed Hawk, owls and Bald Eagles. And then we have started to see it in some of our scavengers as well, crows and ravens in particular. There have been a couple of Blue Jay cases. Turkey Vultures in different parts of North America.”
Brian Stevens goes on to explain some typical Avian Flu symptoms shown by wild birds that are still living. “Typically, what we’re seeing on the wildlife side is neurological signs. Birds that are having difficulty standing, walking or flying. They often have abnormal head movements, and sometimes they will have convulsions and seizures.”