Farm and Home Biosecurity
Livestock/Row Crop Producer
The Bird Flu
There is tremendous concern about a strain of Avian Influenza
(AI) referred to in the news media as the "Bird Flu," "Asian Bird
Flu" or "Avian Flu. " This strain of Avian Influenza has caused
serious problems in poultry and humans in Southeast Asia, Africa,
and Europe. A recent television movie may have added to anxiety
about "Bird Flu" concerns in this country.
Avian Influenza is a disease caused by a virus (Orthomyxovirus).
The virus has two glycoproteins known as hemagglutinin (H) and
neuraminidase (N) that protect the virus and allow it to adhere to
surfaces such as respiratory cells membranes. There are 16 types of
H glycoproteins and 9 types of N glycoproteins. These glycoproteins
are used by poultry health professionals to differentiate strains of
AI (such as H5N2 or H7N1).
In addition, AI is designated as low pathogenic or high
pathogenic depending upon the genetic makeup and mortality levels it
causes in poultry. The type of Avian Influenza known as "Bird Flu"
that is a problem is a highly pathogenic strain of H5N1. This strain
has caused extremely high mortality in poultry and has infected
approximately 205 humans, causing approximately 115 deaths. These
features of the disease have caused great concern.
Originally, Avian Influenza was not believed to spread from birds
to people without first going through an intermediary, such as pigs.
However, in 1997, an outbreak of the virus in Hong Kong poultry did
spread directly to people. It should be noted that many people who
have helped to eradicate infected birds have not fallen ill with the
disease. Unfortunately, a small number of people have developed an
infection from the H5N1 virus. Virtually all of these people have
been in direct close contact with infected birds (there has been one
case of "suspected" human-to-human transmission, but no evidence has
been found of readily sustained human-to-human transmission).
Most of the poultry raised in Southeast Asian nations and Africa
are raised as free range or free running poultry (often referred to
as village poultry), where they co-mingle with other animal and bird
species as well as have frequent contact with people. It is thought
that this practice of allowing poultry to co-mingle with other
species in free-range situations has lead to Avian Influenza
outbreaks. In the United States, commercial poultry are kept
confined in controlled housing and have contact with only limited
numbers of people.
The transmission of the Avian Influenza to people has been very,
very rare. However, the concern is that if the virus mutates and
acquires human influenza genes, it could be transmitted efficiently
from person to person, thus setting the stage for a possible
pandemic (worldwide epidemic). Health officials worldwide are
concerned that the virus might change to one that could cause a
pandemic. However, even if the virus acquires this mutation, a
pandemic will not necessarily begin.
There have been limited outbreaks of Avian Influenza in poultry
in the USA in the past. These infected flocks were humanely
depopulated and disposed of. The poultry houses were cleaned,
disinfected, and checked for virus. There is currently a ban on the
importation of live poultry or poultry products from AI-affected
areas. It is also important to note that almost all of the poultry
sold in the USA is produced in the USA. Avian Influenza monitoring
and surveillance efforts are constantly being conducted in the
poultry industry as an additional safeguard. Because of these
practices and the US food inspection protocols there is virtually no
chance that a person will come in contact with poultry meat or
products that are infected with the Avian Influenza virus.
Normal hygiene practices, such as the washing of hands after
handling raw poultry meat, properly cooking poultry, and preventing
cross contamination, reduce the chances of contracting Avian
Influenza still further. The virus is easily destroyed by normal
cooking temperatures. The current recommendation is to cook poultry
meat until the internal temperature is at least 165 degrees
Fahrenheit. Basic hygiene is recommended by health experts to
prevent contracting any influenza (practices such as covering your
mouth when sneezing or coughing and then washing your hands
afterwards).
A National Surveillance Program for Avian Influenza in poultry is
being conducted in the USA. Poultry flocks are tested for Avian
Influenza before processing. Biosecurity measures in commercial
poultry operations throughout the US are also on high alert. The
biosecurity measures, surveillance efforts, and veterinary practices
in place in the commercial poultry industry lessen the possibility
that disease will enter into commercial poultry flocks. In addition,
these safeguards would quickly detect presence of this disease in
the flocks, resulting in immediate quarantine and depopulation of
the poultry farm where H5N1 was detected. Stringent containment,
cleaning, and disinfection measures would be implemented soon
afterward.
Data this summer and fall suggested that migrating birds may have
spread the virus out from Asia and into other areas. However,
scientists have not been able to link the spread to migrating birds.
Surveillance testing continues, and H5N1 was not detected in
thousands of samples collected in Africa this past winter.
Surveillance efforts of migratory birds in the USA to date have also
not detected this virus.
There is currently no vaccine available commercially to protect
people against H5N1 Bird Flu. However, research efforts to develop a
vaccine are continuing. The United States Center for Disease Control
(CDC) has provided U.S. health departments with recommendations for
enhanced surveillance and detection of H5N1. In addition, the CDC
has issued advisories to travelers visiting countries with outbreaks
of H5N1. Numerous training programs and workshops have been
conducted with state and local health departments to increase
awareness of the disease and enhance the agencies’ ability to detect
H5N1. The CDC is also working with the National Institute of Health
and the World Health Organization to develop vaccine seed stock
candidates and safety test vaccines. Since the development of
vaccines does take several months, preparations are being made in
case the virus changes and develops the ability to spread from
person to person, thus causing a pandemic. Hopefully, the changes in
the virus will not occur, but preparing for potential virus changes
could prevent numerous illnesses or deaths. Should an epidemic
occur, individual state plans and a national plan for dealing with
an epidemic are in place.
There is currently no H5N1 Avian Influenza in the USA. The
current safeguards in place make an outbreak highly unlikely.
However, prevention and surveillance are always prudent.
Poultry producers can help protect their flocks against AI and
other diseases by utilizing biosecurity practices such as those
listed below:
1. Keep "No Visitors" and/or "Restricted" signs posted at the
road entrance of the farm.
2. Do not allow visitors on the farm or in the poultry houses.
3. All farm personnel should wear separate clothing (including
shoes, boots, hats, gloves, etc.) on the farm. Clothes used on the
farm should stay on the farm.
4. Completely change all clothing after caring for the flock, and
wash hands and arms thoroughly before leaving the premises.
5. Do not visit other poultry farms or flocks or have contact
with any other species of birds.
6. Keep all poultry houses securely locked. Lock all houses from
the inside while working inside.
7. All equipment, crates, coops, etc. should be thoroughly
cleaned and disinfected before and after use.
8. All essential visitors (owners, feed delivery personnel,
poultry catchers and haulers, service men, etc.) are to wear
protective outer clothing (coveralls), boots, and headgear prior to
being allowed near the poultry flock or farm.
9. Monitor all vehicles (service, feed delivery, poultry delivery
or removal, etc.) entering the premises to determine if they have
been properly cleaned and disinfected. This includes disinfection of
the tires and vehicle undercarriage.
10. Sick and dying birds should be submitted to a diagnostic
laboratory for proper diagnosis of the problem. All commercial
growers should contact their flock supervisor and follow their
instructions.
11. Dead birds are to be properly disposed of by burial,
incineration, or other approved method.
12. Any person handling wild game (especially waterfowl) must
completely change clothing and shower or bathe before entering the
premises.
13. Do not borrow equipment, vehicles, etc. from another poultry
farm.
14. Do not visit areas where Avian Influenza is suspected.
15. Remember to use basic hygiene (as recommended by health
experts) to prevent contracting any influenza virus (practices such
as covering your mouth when you cough and/or sneeze and then washing
your hands with soap and water afterwards).
16. Properly handle and cook all poultry for consumption
(internal temperature of at least 165 degrees Fahrenheit)
by F. D. Clark, DVM, Ph.D.
Extension Poultry Health Veterinarian
(479) 575-4375
May 12, 2006
Back to Livestock/Row Crop Producer |
