A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 1 May 2009
Source: The Poultry Site [edited]
Low-Path Bird Flu Found in Tennessee
Birds on a farm in Giles County in Tennessee have been found to have
the avian influenza virus. An official commented the virus poses no
threat to human health. 2 poultry houses belonging to one farm in
Giles County are infected with the avian influenza virus, reports
WKSR. That was the determination of state officials following testing
earlier this week [4 May 2009].
According to Giles County EMA Director Barry Whitt, the case 1st came
to light on 27 Apr 2009. State officials came in and ran tests on
some of the birds and made their determination on 29 Apr 2009. Mr
Whitt says that the outbreak is confined to the 2 barns that are
located on the same property.
"This particular strain is confined to the animals only and is not
spread to people," says Mr Whitt. "The public is not in any danger."
Mr Whitt is coordinating with state officials on the next step to
take. The EMA Director says that the plan is for the state to provide
the chemicals and the manpower to clean and decontaminate the area.
The Giles County Fire and Rescue Decontamination crew will supply
equipment and assistance when the clean-up begins.
Mr Whitt said that he will be meeting with state officials to
determine when the clean-up will begin.
ProMED-mail Rapporteur Mary Marshall
[Apparently this was noticed early and quarantined promptly. It would
be nice if we knew the typing on this strain, and if it is related to
the H7 strain that was in Kentucky or if this is different.
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.
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