ARS Takes On Bird and Swine
Scientists are now learning more about
how animals can be hosts for flu viruses. Birds are believed to be a global
reservoir of influenza virus genes that make their way to humans. Since pigs
can be infected with both avian and human strains, they may also be a "mixing
vessel" in the transmission process. When bird influenza viruses infect pigs
that already contain a swine or human influenza virus, gene segments from each
virus can mix and a new influenza subtype virus can emerge.
Centers for Disease Control and Prevention (CDC) reported earlier this
month that approximately one half the expected supply of flu vaccine available
in the United States for the 2004-05 influenza season will not be available
over concerns about standards at the manufacturing plant.
The flu virus goes through mutations, so
the flu vaccine has to be reformulated each year based on the strains of flu
that previously appeared.
Humans can be infected with influenza
types A, B, and C. Influenza A and B are the most important strains. Type A
affects mammals (such as humans and pigs), as well as birds, but types B and C
affect only humans.
Oftentimes, the losses for swine and
poultry producers can be devastating. When Virginia experienced an outbreak of
avian influenza (H7N2) in 2002, for example, 4.7 million turkeys and chickens
avian influenza type A virus (H5N1) infected both chickens and humans in 1997,
ARS was ready to help. The Hong Kong incident marked the first time an avian
influenza virus had ever been found to transmit directly from birds to humans.
ARS scientists already had a working H5 influenza vaccine for birds at the
time. The ARS
Poultry Research Laboratory (SEPRL) in Athens, Ga., was studying a viral
strain called H5N2. This strain attacks only poultry but is related to H5N1,
the Hong Kong bird flu strain. Their research allowed them, and industry
cooperators, to provide
the Hong Kong government with the poultry vaccine.
Researchers at SEPRL want to understand
why and how mild viruses become highly pathogenic and are developing better
diagnostic tests with improved vaccines. The molecular research includes
characterizing genes using a rapid polymerase chain reaction (PCR)
procedure, sequencing of the entire virus genome of representative isolates,
and creating molecular models.
Athens researchers are studying the
behavior of the viruses in living hosts and hope to better understand how
certain strains evolve to be so pathogenic and to develop ways to predict this
The H5N1 influenza strain turned up again
in early 2004 in a few people who died from bird flu in Vietnam and Thailand.
The virus killed 30 people in Asia earlier this year. Other nations in
Southeast Asia have reported fresh cases of bird flu in poultry in past weeks,
months after a mass culling campaign in which tens of millions of poultry were
destroyed. The strain has spread widely among poultry and other birds in
Southeast Asia and infected people there.
H5N1 also is known to have infected pigs
as early as last year. H5N1 has since crossed another species barrier to infect
cats. Dutch scientists have found that the virus can also spread among cats.
It's not known whether cats can transmit the virus strain to humans.
Historically, only one type of swine flu
virus, H1N1, was primarily found in pigs in the United States. That changed in
1998 when the H3N2 strain showed up here in swine, and most recently, the H1N2
Animal Disease Center in Ames, Iowa, scientists are working on ways to
control swine flu. Part of their research includes developing immunogens that
provoke a protective immune response when introduced into a body. They also
want to develop diagnostic reagents that can be used to detect the presence of
swine influenza in pigs.
Ames researchers in the Virus and Prion
Diseases of Livestock Research Unit and their collaborators use a process known
genetics to create swine flu types that could one day help develop a
vaccine and stop the rapid spread of the virus.
For more information, contact the
Swayne, Athens, Ga.
Lager, Ames, Iowa
Richt, Ames, Iowa
Findings from an ARS researcher in Arkansas
could be instrumental in the development of
a year-round supply
of sunshine bass fingerlings.
ARS recently opened a new facility to study
stress indicators in
livestock. One issue the West Lafayette, Ind., laboratory will examine
involves the relationship between stress and the ability of pathogenic bacteria
to establish themselves in animals.
C. Lay, Jr.
ARS and cooperating scientists named
a new genus of
bacteria found in swine manure after a late microbiologist.
A gene that helps regulate feed intake and
energy expenditure in turkeys has been sequenced by ARS scientists. The gene
codes for the production of the hormone called
USDA officials and scientists hosted the
Foot and Mouth Disease
Global Research Alliance to discuss collaborative research in developing
better vaccines and antiviral agents against the virus that causes FMD.
An ARS microbiologist used
proteins from harmless
microorganisms to reduce Campylobacter and other pathogens by 99.999
percent in poultry intestines.
Methods developed by ARS scientists in Texas are
helping Scottish scientists
control ticks that
are spread from wildlife to game birds.
ARS researchers developed
two new methods to
detect the presence of feed additives used to produce leaner cuts of pork and
L. Shelver and
(701) 239-1425 [Shelver], (701) 239-1238, [Smith]
Jitender P. Dubey, a microbiologist with the ARS
Parasite Biology, Epidemiology and Systematics Laboratory in Beltsville, Md.,
was one of several ARS personnel to win a "Presidential Rank Award" for 2003.
research into the biology and control of toxoplasmosis, neosporosis and
equine protozoal myeloencephalitis has saved billions of dollars worldwide in
healthcare and livestock production costs.
David L. Suarez and team members with ARS
Southeast Poultry Research Laboratory in Athens, Ga., were recognized at the
58th Annual Secretary's
Honor Awards Ceremony held in the Ronald Reagan International Trade Center
in Washington, D.C. They received the prestigious award for developing and
implementing rapid diagnostic tests, vaccine evaluation and policy development
to control an exotic Newcastle disease outbreak in the United States.