Thursday, May 2, 2013

National Wildlife Disease Surveillance & Emergency Response Program Detects H7N9 in U.S. Poultry 2009

[I found this in 2009 circulation of The Carrier Vol 1 Issue 3, June 2009]:
National Wildlife Disease Surveillance and Emergency Response Program

In April and May, three different poultry
operations in Kentucky and Tennessee had
positive serum test results for low patho-
genic avian influenza (LPAI). The geographi-
cally isolated breeder houses discovered the
results during a regularly scheduled testing
for influenza virus. However, clinical signs
were minimal with no significant increase in
mortality and only a slight decrease in egg
In early April a breeder facility in Kentucky
was found to be positive for LPAI. At the end
of April, a breeder facility in Tennessee re-
ported its first positive case, and the Ten-
nessee Department of Agriculture (TDA) and
USDA, APHIS, Veterinary Services (VS) set up
a Command Post and implemented the Inci-
dent Command System (ICS). WDB J.D.
Freye was invited to participate and work
with the epidemiologist investigating possi-
ble causes for the outbreak. In the first
week of May, a second
breeder facility in TN
reported positive LPAI results. All three fa-
cilities, including the one in KY,
had the virus
typed as H7N9. All three companies had
bio-security policies an
d procedures in place
at the time of infection and there was no
apparent common link between the facili-
ties. Thus, the investigators became suspi-
cious of wild birds possibly causing the in-
fections, so Wildlife Services (WS) was
asked to conduct wild bird surveillance
around the two TN facilities.
The virus was determined to have infected
the facilities some time in March. March is
also the time when several birds begin their
nesting season and birds like starlings and
sparrows commonly nest
in or around build-
ings. Therefore, WDB Freye concentrated the
wild bird sampling on birds that were nesting,
roosting, or loafing at the infected facilities.
Several bird species were tested using blood
serum, looking for influenza titers. All of the
samples tested negative. Under direction of
the ICS, WS also aided TDA and VS with col-
lecting domestic birds in backyard flocks for
surveillance within a three mile radius of the
infected premises.
Wild bird and backyard surveillance did not
produce any positive titers for avian influ-
enza, resulting in the cause of the outbreak
to remain undetermined. After the incident in
TN, there were more H7N9 virus infections
found in poultry facilities in other states, so
wild birds are still suspected of being the
cause of the outbreaks. This outbreak has
been devastating for the involved states’
poultry industry, costing the producers and
companies millions of dollars in loses. In
addition, other producer
s within the affected
states also lost millions of dollars because of
increased biosecurity and testing, as well as
losing the ability to expo
rt poultry products to
several countries. These LPAI outbreaks are
a good example of how a seemingly small or
local event indeed can be serious enough to
cause negative impacts
to agricultural pro-
ducers and businesses. These responses
also highlight the importance of testing wild-
life prior to making an epidemiological deter-
mination of the source of infection. 

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