POULTRY HEALTH
Poultry researchers continue
focus on avian influenza
Researchers are tracking avian in;uenza, studying factors involved in its pathogenicity and
testing new approaches to vaccination.
BY DUSTAN CLARK
Avian in;uenza continues to be a topic for
discussion and research because outbreaks
in poultry can cause high losses in poultry,
pose a threat to human health and adversely
impact the international trade of poultry
products.
Most strains of the avian in;uenza virus
are considered to be of low pathogenicity.
However, the H5 and H7 strains are of
particular interest since these strains have
been responsible historically for highly
pathogenic outbreaks in commercial poultry. The “bird ;u” that has been in the news
is the Asian strain of an H5N1 avian in;uenza, and the disease persists as a problem
with 49 human cases as of November 2011.
The economics associated with controlling
these outbreaks can cost millions of dollars
with huge losses of birds. Research concerning numerous diseases was presented
at the 2011 meeting of the Poultry Science
Association and the American Association
of Avian Pathologists. Some of the diseases discussed included Runting Stunting
Syndrome, Marek’s disease, infectious bursal disease, avian in;uenza and coccidiosis.
Avian in;uenza, however, was the subject
❯❯
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Use of water-based foam is considered an appropriate method of depopulation of floor-reared
poultry in accord with USDA-APHIS performance standards.
of numerous reports and the focus of two
sessions at the meeting.
Surveillance shows AI
prevalence, antibodies
The AI virus is known to be in wild birds.
In fact, the natural reservoir of the virus is
waterfowl and various species of shorebirds.
The virus is also known to readily mutate.
These two factors make surveillance efforts
in waterfowl migratory ;yways and in domes-
tic poultry critical in establishing what strains
are present in the
natural reservoir. A
research report by
B. Lupiani of Texas
A&M University
presented data from
a multi-year study
of avian in;uenza in the Central Flyway.
Over 7,000 cloacal swab samples were col-
lected and tested for AI. The majority of
the samples collected (over 85%) were from
dabbling type ducks. The samples were
tested using RT-PCR testing and all positive
samples were processed for virus isolation.
A total of 607 samples were positive on the
RT-PCR test and of those 155 AI viruses
were isolated. The most common subtypes
isolated were H3N8 and H4N6. This research
in birds in an understudied ;yway showed
that during the ;ve years of the study no H5
F.D. Clark, DVM, PhD, Extension Veterinarian
and Interim Associate Center Director of
Extension, O205POSC Center of Excellence
for Poultry Science, University of Arkansas;
phone 479.575.4375
