# 5132
After several major bird flu outbreaks over the years, including the wave of H5N1 that swept the country’s poultry farms in 2008 (see here, here, and here), South Korea now mounts an aggressive annual surveillance program starting each fall and running through the spring.
The incidence of H5N1 infection among wild birds, and their role in spreading the disease, has been a subject of considerable debate over the years.
We’ve seen conflicting studies (and a good deal of rhetoric) that either implicate or exonerate wild or migratory birds as significant vectors of the virus.
A few blogs on that contentious debate include:
Another Migratory Bird Study
Not One Of The Usual Suspects
FAO: On The Trail Of Avian Influenza
The Migratory Bird Connection
India: The Role Of Migratory Birds In Spreading Bird Flu
The poultry industry would, naturally, like to lay the problem mainly at the perch of wild and migratory birds. Naturalists tend to see poor biosecurity in poultry operations - and the illicit poultry trade - as the real culprits.
Personally, I’ve never seen any reason why these should be viewed as mutually exclusive options. Both could be major contributors, perhaps with one being a bigger factor than the other depending on where in the world you happen to be.
As one might suspect, when you actively look for bird flu . . . you are more apt to find it. At least in those regions (primarily Asia) where the virus is endemic.
And so it was of little surprise that earlier this week South Korea announced the discovery of a single duck at a wild migratory habitat that tested positive for the H5N1 virus.
2010/12/08 00:41 KST
S. Korea confirms bird flu outbreak in southern province
SEOUL, Dec. 8 (Yonhap) -- The South Korean government confirmed on Tuesday a bird flu outbreak in a southwestern region of the country, a main winter habitat of migratory birds.
The agricultural ministry said the state veterinary service confirmed that the bird flu virus was found in one of the blood samples sent from Iksan, North Jeolla Province.
The ministry conducted an emergency disinfection of the area around the Mangyeong River, where the infected wild bird was found, and put an area within a 10-kilometer radius from the site of the outbreak under intensive care.
While calling a lone infected duck an `outbreak’ might seem to be stretching the definition a bit, H5N1 is a communicable disease in birds, and so where you find one you are apt to find others.
Today, Yonhap news is reporting on the discovery of two more infected birds, although the location given is too vague to tell how far removed these cases are from the one reported earlier this week.
First the news report, then a little more.
2010/12/10 17:34 KST
S. Korean quarantine officials find dead owls affected by bird flu
SEOUL, Dec. 10 (Yonhap) -- South Korean quarantine officials found two dead eagle owls infected with the virulent strain of bird flu in the central western part of the country on Friday.
The farm ministry, however, said that the discovery of the owls did not mean South Korea was affected by the disease since no domestically raised ducks and chickens have become sick from the highly contagious influenza. Exports of poultry will not be affected by the discovery, it stressed.
Eurasian Eagle Owl (Bubo bubo)
While the List of Species Affected by H5N1 (Avian Influenza) is long (and growing), somewhat surprisingly, owls have only rarely been mentioned.
Most wild birds are thought to become infected through the sharing of virally contaminated water sources. H5N1 is primarily a gastrointestinal infection in birds, and is generally believed spread through infected feces.
Owls, as opportunistic hunters - have another likely route of infection; the consumption of infected prey.
The Eurasian eagle owl is one of the largest owls in the world, and so is quite capable of taking medium sized quarry. Its diet includes mice, rats, rabbit, squirrels and other birds.
A scan of the USGS H5N1 database shows that rats, mice, and even rabbits ((a veritable smorgasbord for owls) . . . along with many species of birds, have all been discovered carrying the H5N1 virus.
So the discovery of two dead owls leads one to suspect there are more infected birds and/or animals in the region.
While the detection of a few wild birds with H5N1 in one week in Korea is hardly alarming, it is a reminder that the virus continues to exist, and spread, in the wild.
So surveillance efforts, such as the one ongoing in South Korea and those mounted each year by the USGS, are important measures to help quantify, control, and contain the threat.
