Farm and Home Biosecurity
Livestock/Row Crop Producer
The The Avian or Asian Bird Flu
Recently, there has been a 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.
Avian Influenza is a viral disease caused by a virus (Orthomyxovirus). The
virus has two glycoproteins known as Hemaggultinin (H) and Neuraminidase (N)
that protect the virus and allow it to adhere to surfaces such as respiratory
cells membranes. There are 15 types of H glycoproteins and 9 types of N
glycoproteins. The two 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 currently in
Southeastern Asian nations is a Highly Pathogenic strain of H5N1. This strain
has caused extremely high mortality in poultry and has infected 100+ humans
causing approximately 65 deaths. It is these features that have caused the great
concern over the disease.
Normally, Avian Influenza was not considered to spread from birds to people
without first going through an intermediary such as pigs. However, in 1997 in an
outbreak in Hong Kong poultry the virus did spread directly to people. Yet, it
should be noted that many people have been associated with the eradication
efforts and have not fallen ill with the disease. Unfortunately, a small number
of people have developed an infection from the virus. Virtually, all of these
people have been in direct close contact with infected birds.
Most of the poultry raised in Southeast Asian nations 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 the very rare
exception. 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). It is this
concern over the possible change in the virus to one that could cause a pandemic
that has health officials worldwide anxious.
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 and
properly cooking poultry reduce the chances further since the Avian Influenza
virus is easily destroyed by normal cooking temperatures.
There is currently no vaccine available commercially for protection of people
against H5N1 "Bird Flu". However, research efforts to develop a vaccine are
continuing and clinical vaccine test trials were conducted in April of 2005. The
United States Center for Disease Control (CDC) has provided US Health
departments with recommendations for enhanced surveillance and detection of H5N1
and have 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 H5N. 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. These preparations are being done to
be ready 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 the efforts to be prepared if the virus changes could prevent
numerous illnesses or deaths. 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 a problem.
by F.D. Clark, DVM, PhD, Extension Poultry Health Veterinarian
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