Monitoring for Avian Flu
General Information
Chipper Woods Bird Observatory participates in a North
American-wide early warning network of monitoring stations to
sample wild birds for Avian Influenza.
Influenza is a group of some 144 strains of type A viruses
that infect the digestive system of birds. Some of these strains
can infect humans, others cannot. Two types of antigens occur on
the surface of the spherical virus particle. The 16 types of
Hemagglutinan (HA) antigens help the virus to attach to,
penetrate and infect the host cell. The 9 types of Neuraminidase
(NA) help the new virus particles exit the host cell. It is the
various combinations of the HA and NA antigens that result in
the 144 different strains of avian influenza.
Most of these viruses are Low Pathogenic Avian Flu (LPAI),
but occasionally a more serious High Pathogenic Avian Flu (HPAI)
emerges. The early warning network is designed survey the types
of flu that North American birds are currently carrying, and to
provide an early detection of the HPAI H5N1strain that now
occurs in Asia, Africa and Europe if it should arrive in the
Americas.
Waterfowl, especially the Mallard Duck, are the primary avian
reservoirs, but shorebirds, gulls and terns also act as
reservoirs of avian flu.
Songbirds are rare sources of avian flu. Raptors, Cranes,
game birds, and Marine birds are also rare to occasional sources
of avian flu. Shorebirds are most likely to show infections in
the spring and fall. Waterfowl are most likely to show
infections in the summer and fall.
Avian flu very rarely jumps directly from birds to humans, so
there is no need to worry about feeding birds in your backyard.
It is more likely that an intermediate animal, such as a pig,
will acquire the infection, and genetic mixing of the virus in
the infected pig will allow it to acquire the genetic
combination needed to infect humans.
The H1N1 strain of flu, also known as Swine Flu, is now
spreading at Pandemic proportions around the world. World
leaders are concerned that the genome that makes the H5N1 avian
flu so deadly may mix with the swine flu H1N1 strain resulting
in a deadly Pandemic similar to the 1918 outbreak. Only time
will reveal whether this fear will come true or not.
So how do we sample wild birds for avian flu? The procedure
is fairly simple.
|
