Published Date: 2009-04-05 14:00:51
Subject: PRO/AH/EDR> Avian influenza (LPAI), poultry - USA (KY): H7
Archive Number: 20090405.1314
AVIAN INFLUENZA (LPAI), POULTRY - USA (KENTUCKY): H7
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 4 Apr 2009
Source: LEX18.com [edited]
State and federal authorities are investigating a finding of
suspected non-pathogenic or low-pathogenic avian influenza in a
single broiler/breeder poultry farm in western Kentucky. The strain
poses minimal risk to human health and is not the high pathogenic
strain associated with human and poultry deaths in other countries.
State Veterinarian Robert C. Stout has quarantined the farm, which
produces hatching eggs for Perdue Farms Inc. Perdue plans to
depopulate 20 000 chickens in 2 houses on the farm.
"The state and federal government and Perdue are acting aggressively
to contain and eliminate the disease," Dr. Stout said. "There is no
evidence that any infected poultry are in the human food supply as a
result of this infection. We will do what is necessary to minimize
the disruption to overseas trade."
"I have been in constant contact with state, federal and industry
officials since this came to light," Agriculture Commissioner Richie
Farmer said. "The people of Kentucky and our trading partners should
rest assured that we are doing everything possible to address the situation."
The Kentucky Department of Agriculture is conducting surveillance on
backyard flocks within a 2-mile radius of the farm.
A minimal drop in egg production at the farm was noticed in mid-March
2009. Perdue's veterinary services laboratory took samples from
chickens at the farm and found antibodies for avian influenza.
Testing by the National Veterinary Services Laboratory in Ames, Iowa
resulted in a presumptive positive finding for the H7 strain.
Subsequent testing by NVSL and the Breathitt Veterinary Center in
Hopkinsville confirmed the finding.
No virus has been isolated, and no poultry deaths have been found in
connection with the infection.
Avian influenza is a virus that affects domestic poultry and some
wild birds. It is spread to healthy birds by direct contact with
infected birds or infected material, often through feces from infected birds.
Avian influenza is not transmitted through eggs. Low-pathogenic avian
influenza causes little if any illness in poultry and is rarely fatal
ProMED-mail Rapporteur Mary Marshall
[Fortunately, this case was noticed right away, and samples were sent
for diagnosis. Low pathogenic avian influenza, when it smolders along
for a period of time, can mutate and become more difficult to
control. But this appears to have been caught early, is quarantined,
and it appears that veterinarians, industry and regulators are
working closing to eliminate all risk associated with this outbreak.
The designation of low or highly pathogenic avian influenza refers to
the potential for these viruses to kill domestic poultry. The
designation of "low pathogenic" or "highly pathogenic" does not refer
to how infectious the viruses may be to humans.
Most strains of avian influenza are not highly pathogenic and cause
few signs in infected wild birds; however, in poultry, low pathogenic
strains can mutate into a highly pathogenic avian influenza (HPAI)
strain that causes extremely contagious, severe illness, and often
death in poultry.
Influenza viruses are also differentiated by 2 proteins,
hemagglutinin (H) and neuraminidase (N), which are found on the
surface of the virus. There are 144 theoretical combinations of the
16 different H and 9 different N proteins that make up the subtypes
of avian influenza.
These subtypes can be further genetically differentiated into
strains. A subtype such as the highly pathogenic H5N1 avian influenza
virus may have multiple strains. These different strains may be more
or less pathogenic to domestic poultry, wild birds, humans and other mammals.
Highly pathogenic avian influenza viruses in poultry are usually H5
or H7 subtypes of type A influenza, although low pathogenic forms of
these H5 and H7 viruses also exist.
Portions of this comment were extracted from:
[For the interactive HealthMap/ProMED map of Kentucky, USA, with
links to other recent ProMED-mail postings in surrounding areas, see
<http://healthmap.org/r/008w>. - Mod.MPP]