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High
Pathogenicity H5N1
Avian Influenza and Falconry
The
following report was excerpted from the NAFA Task Force
on Avian Influenza (March, 2006)
The purpose of this article is to give NAFA members information
about avian influenza and inform them of steps NAFA, in
concert with international falconry organizations is taking.
In late February,
2006, President Darryl Perkins appointed a task force
to address the issue.
The members are:
Dr
Pat Redig, DVM, PhD - Chairman
Patrick
Morel - IAF President /European Liaison
Mark
Williams - Canadian Liaison
Bill
Johnston - IAF Liaison
Dr.
Bill Ferrier, DVM - NAFA/Conservation Committee Chairman/
DVM
Alberto
Palleroni , PhD - Harvard Ecologist
Bob
Berry - NARBA President / Breeder
Cal
Sandfort - Peregrine Fund Breeding Specialist
Victor
Hardaswick - Biologist / Breeder
Dr.
Bill Cornatzer , MD - Physician
Roger
Johnson - Quail Breeder
*Darryl
A. Perkins - NAFA President
*Frank
Bond - NAFA General Counsel
The charge given
by President Perkins was to "gather all the pertinent
information and make recommendations for the best course
of action."
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Overview
of the current situation:
Birds,
especially waterfowl, are the natural host of Type A Influenza
viruses (there are types A, B, & C).
Types B and C are not part of the present concern.
There are 144 major types of influenza A viruses and wild
birds, especially waterfowl, are the natural host for
all of them. Ordinarily, no disease is caused in the natural
host.
The
Type A influenza viruses are identified by a pair of proteins
on the external surface of their capsule, the hemagluttinins
and neuraminidases. There
are sixteen known types of hemagluttinins (H) and 9 types
of neuraminidases (N), giving 144 different combinations
of H's and N's. For examples, H3N2 is a common influenza
virus found in poultry, swine and humans in the U. S. The Spanish Flu epidemic of 1918 was caused
by an H1N1 virus, that is still present among us, but
most everyone is immune to it so it causes no disease.
The current concern is with the H5N1 Virus with
hemagluttinin types H5, H7, and H9 are the forms that
have shown the greatest capacity to pass from birds to
humans and to develop into strains capable of causing
severe disease - i.e. high pathogenicity strains.
Most
of the time, Type A viruses circulate in their bird hosts,
waterfowl and aquatic shore birds, as low pathogenic forms
- that is they pass from duck to duck and cause no disease.
If a low path form is introduced into a novel host,
such as a turkey or a chicken, it most often causes mild
disease characterized by depression, runny noses and in
a flock of layers, a decrease in egg production.
In fact, in poultry influenza is known as "egg
drop" syndrome.
In
a few cases, when the virus is introduced into a new host
and is passing from bird to bird, becoming more adapted
to that host as it does, it may randomly evolve into a
high pathogenic form and cause severe disease and death.
This is apparently what happened in the early 1990's
in China when the current H5N1, formerly a low pathogenic
virus in waterfowl, became introduced into domestic chickens.
It appears that it circulated in the live bird
markets and small poultry operations for possibly several
years before it changed into a high path form probably
around 1995 or 1996.
In the process of making that change, it also developed
the capacity to pass from bird to human and cause disease
in them also.
In
a strange twist of fate, this high pathogenic (HP) H5N1
was reintroduced into wild waterfowl in northwestern China
in the spring of 2005, causing a die-off in roughly 1,500 or so bar-headed geese (Anser indicus)
at Qinghai lake
in Western China (Nature vol 436: 191 July 2005).
At the same time it was spreading rapidly throughout
eastern China, Viet Nam, Cambodia and Laos, causing death
in thousands of chickens, some domestic ducks and several
dozen people. Attempts
to contain the virus resulted in the mass culling of millions
of chickens. In
the fall of 2005, the virus was seen spreading westward
along the border of southern Russian states with Kazakhstan
and by the first of the year, it was as far west as the
Danube River delta in Romania.
In January 2006 it popped up in domestic turkeys
in Turkey and in February, it inexplicably appeared in
chickens in the African nation of Nigeria. Also, there was an isolated incident in Saudi
Arabia wherein a Saker falcon in a veterinary hospital
died of H5N1. The most westward human deaths were those
of three family members in Turkey. In late February, several dead mute swans were
found in various places in Europe. By the end of February,
H5N1 was in Germany, France, Italy, Poland, and the Balkan
states. Though reactions vary from country to country,
in most places it has been required that all outdoor poultry
be brought under cover and import/ export restrictions
were placed on poultry and other birds.
It remains to be seen what the duration of any
of these limitations will be and that won't be known until
more is known about this virus.
From
the early westward movements of the virus out of China,
migratory birds were incriminated as a vehicle. However, the movement of the virus has been in
more of an east-west direction than one following the
known migratory bird pathways. Further the movement was occurring at a time of
year when migratory birds were not. It is possible that regional movements of some carrier
species, such as the mute swan or the migratory whooper
swan could account for some of the introductions. However, the distances that the virus traveled
were vast, and except for swans, there were no mass die-offs
of waterfowl being reported.
Additionally, most outbreaks in widely separated
areas repeatedly turned up in poultry, begging the question
as to what role movements of poultry in commercial trade
and the exchange of fighting cocks were playing in the
spread.
HP
H5N1 Influenza in North America
It
is regarded as inevitable at this point that HP H5N1 will
arrive in North America. When and where will depend on the route of
introduction. If
by migratory birds, it is believed that species such as
tundra swans, pintail ducks, and sandhill cranes, among
26 species of birds known to cross over from North America
into Siberia, could introduce it into Alaska.
From there it could spread through any of the flyways
and be distributed throughout the continent.
On the other hand, given the trade, some of it
illegal, in uncooked poultry products that occurs between
the U.S. and SE Asia, as well as birds of various types
in unregulated live bird markets, it could just as well
be introduced through trade routes.
Within the next few months and continuing indefinitely,
a great deal of surveillance in wild birds and in live
bird markets will be implemented, some of it ongoing already
for several years, to attempt to detect the introduction
of the virus. The USDA and USFWS will expend $7.4 million
in Alaska in 2006 alone for surveillance. Despite
all of this surveillance aimed at detecting introduction,
it is most likely that detection will occur as a consequence
of a die-off of waterfowl someplace. Either way, information networks are in place
and it will be known almost immediately.
Vaccines?
A
high-tech recombinant vaccine for birds against avian
flu, that is under development by Fort Dodge, is scheduled
for testing in zoo collections in the near future. This
work is being coordinated by the Association of Zoos and
Aquaria.
Falconers and HP H5N1
Despite
the uncertainties of where and when the virus will show
up, it is important for falconers (or other bird handlers) to prepare for the
day that it does. This
preparation needs to necessarily include an understanding
of the risks posed to one's birds, both direct and indirect.
Risk of infection occurs in exposure from captured
prey, from food sources, and from contamination.
The
virus is very hardy and travels well on vehicles, clothing
and utensils. Where vaccines
are being used in poultry, it is controversial and typically
utilizes one made for use against H5N2, a close relative. However the vaccine has not been tested for
efficacy against HP H5N1 and there is a very real risk
that it will allow the virus to circulate undetected at
a subclinical level).
Indirect
risks are largely associated with the response of regulatory
officialdom. There are ongoing discussions between them
and entities such as zoos and outdoor range-rearing poultry
operations to establish guidelines for the response.
Another risk lies in the public and media response
that arises from a confirmed detection of the virus and
the collateral damage that may arise from that.
These
and many other related issues will be thoroughly investigated
by this task force. In the meantime, it is important to remember
that the focus is on the HP H5N1 influenza virus only. There
are many other influenza types around and anyone who has
been duck (hunting) has been exposing themselves to these
viruses for as long as they've been pursuing those activities,
including low path H5N1. Until HP H5N1 shows up, nothing has changed. When it does, everything will be impacted.
There
are several up-to-the-minute sources of information that
(interested people) can access on the internet to stay
abreast of the most current information about the occurrence
of H5N1 and some of the responses to its activity. They are listed as follows:
http://www.pandemicflu.gov/ - One stop access to U.S. Government avian and pandemic
flu information. Managed
by the Department of Health and Human Services.
http://www.aphis.usda.gov/vs/npip/
- web site for national poultry improvement plan - gives
information about biosecurity for avian species and provides
a registry of poultry producers that are registered in
this plan.
http://www.aphis.usda.gov/vs/birdbiosecurity/hpai.html
- guidelines for providing biosecurity for poultry, some
of which is applicable to falconer's birds.
Promed
(subscribe at: majordomo@promedmail.org)
- this site provides updates, multiple times daily, on
the latest reports regarding avian influenza and many
other diseases of human and animal concern.
World
Animal Health Organization (OIE - http://www.oie.int/eng/en_index.htm). Provides up-to-date information on animal diseases
on a regular basis. A
good source of information on meetings, information exchanges,
and policy development for combating animal diseases.
Much information about HP H5N1.
*The NAFA President and General Counsel are de facto members
of all NAFA committees.
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