Published Date: 2004-02-14 23:50:00
Subject: PRO/AH> Avian influenza - USA (DE) (06): OIE
Archive Number: 20040214.0488
AVIAN INFLUENZA - USA (DE) (06): OIE
A ProMED-mail post
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International Society for Infectious Diseases
Date: 13 Feb 2004
From: ProMED-mail <email@example.com>
Source: Office International des Epizooties(OIE), Disease Information [edited]
Avian influenza in the USA
Information received on 9, 10, 11 Feb 2004 from Dr Peter Fernandez,
associate administrator, Animal and Plant Health Inspection Service
(APHIS), United States Department of Agriculture (USDA), Washington, DC:
The report is dated 11 Feb 2004 and refers to an animal health incident
first detected 5 Feb 2004 (estimated date of primary infection 2 Feb 2004).
Nature of diagnosis: clinical and laboratory.
Two outbreaks are reported, both in the state of Delaware (north eastern
United States): one in Kent County and one in Sussex County
Description of affected population:
- The farm in Kent County is a non-commercial operation and functioned like
a backyard flock (no biosecurity, no all-in all-out system) and had a
mixture of poultry breeds of different ages. The flock consisted of about
5000 chickens 5 weeks old, 4800 white roosters and 1200 red pullets, all in
one house. Only the 5 week old chickens were clinically affected. They were
separated from the rest of the birds by wire mesh, and although these older
birds (the roosters and the pullets) did not appear to be clinically
affected, they were directly exposed to the same agent, and therefore,
- The farm in Sussex County is a commercial broiler operation. All birds on
the premises were about 4.5 weeks old.
Total number of animals in the outbreak:
species / susceptible / cases / deaths / destroyed* / slaughtered
avi / about 85 800 / ... / low mortality / about 85 800 / 0
* Note by the OIE Animal Health Information Department: the number of birds
mentioned in the "destroyed" column includes the number of chickens dead
from the disease.
The diagnosis was made at Lasher Laboratory, University of Delaware,
Georgetown, Delaware. Further testing is being conducted at the National
Veterinary Services Laboratories (NVSL) in Ames, Iowa.
Diagnostic tests used:
- agar gel immunodiffusion;
- enzyme immunoassay membrane test;
- real-time PCR (polymerase chain reaction).
- Outbreak in Kent County: The specific strain of avian influenza virus
detected in the affected farm has been confirmed as H7N2. All the isolates
sequenced are basically identical to recent H7N2 viruses from the live-bird
markets in the north east of the United States. The sequence at the
cleavage site is PEKPKPR/GLF, a sequence that is consistent with low
- Outbreak in Sussex County: The causal strain is also H7. The
neuraminidase component and its pathogenicity are pending.
A. Source of agent / origin of infection: unknown at this time.
B. Other epidemiological details:
- The outbreak in Kent County (index outbreak) was detected on 5 Feb 2004.
- The outbreak in Sussex County was detected on 10 Feb 2004. It is located
about 10 km south of the outbreak in Kent County.
- Birds raised on the affected premises in Kent County were being sold
specifically to supply the live bird markets in New York City.
- Poultry premises within a 3-km radius of the outbreak in Kent County have
been sampled and tested. All 20 commercial farms within this radius tested
negative for avian influenza.
- Stamping out.
- A quarantine zone has been implemented within a 3 km radius of the outbreaks.
- USDA-APHIS is working closely with the state of Delaware by conducting
epidemiological investigations and area surveillance testing.
- The state of Delaware has cancelled all farmer and poultry grower related
meetings, all sales and auctions of farm equipment, and all sales of live
Note by the OIE Animal Health Information Department: Only highly
pathogenic avian influenza is on the OIE List A of diseases. The
information in the above report seems to indicate, subject to confirmation
by the biological tests currently in progress, that the virus in question
is low-pathogenic and unrelated to the one currently circulating in some
East Asian countries.