David E. Swayne, DVM, PhD
Laboratory Director
Southeast Poultry Research Laboratory
USDA/ARS
934 College Station Road
Athens, Georgia
Telephone: 706-546-3433
Fax: 706-546-3161
Personal correspondence with Dr. David E Swayne (USA)
concerning the AI problematic
Dear Dr. Lanneau
The email I sent to Dr. Chalmers is factually correct, the
commentary he placed
on my statements are not within the context which I had
answered his questions
over 4 months ago. The original questions he sent me were:
A nearby city of close to 1 million people (Calgary,
Alberta, Canada) is proposing
a bylaw to ban pigeons on the basis of their concerns about
Avian Influenza,
etc.. I have been asked to respond to these concerns, so was
wondering if there
is anything new from your research on the strain that was
allegedly causing
illness in pigeons and school children in SE Asia. I'd be
grateful if you could
provide any update on the virus and its relationship to
illness in pigeons. Many
thanks for any help you can offer. Kind regards, Gord
Chalmers, DVM.
My response was:
Dr. Kaleta recently published review of Avian Influenza (AI)
in pigeons and
concluded, as I also believe, that pigeons are resistant to
avian influenza viruses
and have not been a reservoir or vector of the virus.
DTW.Deutsche.tierarztliche.Wochenschrift 111(12):467-472,
2004.
Other studies have support the resistance of pigeons to AI
virus infections.
Some people have confused die-offs in pigeons to avian
influenza when
paramyxovirus type 1 is a common cause of neurological
disease and death in
pigeons and not avian influenza.
We have conducted experimental studies in pigeons using
viruses isolated from
dead pigeons in Thailand. Even direct inoculation of these
viruses into nasal
cavity of pigeons caused limited infections with between
60-80% of the pigeons
not becoming infected. This suggests the mortality from H5N1
HPAI virus in
pigeons may have resulted from synergy between AI infection
and some other
pathogen.
The "illness in school children" is an unsubstantiated
rumor. No AI virus was
isolated from the children and I am unaware of any evidence
of infection.
With this scientific information, it is unlikely that
banning pigeons will have any
impact on AI ecology and will not reduce the risk AI
infections of poultry or
humans. The primary species that have natural infections
with AI viruses are
wild ducks and shorebird (turnstones, gulls, etc.).
Columbiformes and passerines
are not reservoirs and they are rarely incidental hosts
following spill-over of the
viruses from infected domestic poultry.
Some rebuttal to misinterpretation of my earlier statements.
1) The comments in the last paragraph above refer to global
ecology of LPAI
viruses, not specific to the Asian H5N1 HPAI virus (I used
specifically different
terms in the first half of the email - Asian H5N1 HPAI
viruses- verses AI
ecology in the last paragraph). Which is historically
correct - pigeons are
resistant to LPAI viruses and have not been involved in the
ecology on a
worldwide basis.
2) The banning of racing pigeons in Calgary, a location that
does not have the
Asian H5N1, would have no impact of the broad ecology of AI
viruses since they
are not the natural hosts of wild bird LPAI viruses. This
would be predominately
some species of wild ducks and shorebirds. This does not
mean that pigeons are
not susceptible to some AI virus; i.e. Dr. Kaleta's comment
on H7 infections.
However, surveys of pigeons have shown either no natural
infections or rare
infections (except with Asian H5N1 HPAI virus where die-offs
of pigeons and
infections have been identified).
3) My research data in pigeons as cited in paragraph 3 above
shows that pigeons
can be susceptible to the more recent Asian H5N1 HPAI
viruses. This was not
the case with the 1997 Hong Kong H5N1 HPAI virus where the
virus did not
grow in pigeons after intranasal inoculation. This would
indicate, in geographic
areas with new Asian H5N1 HPAI viruses circulating in wild
birds or poultry,
restricting the flying of pigeons would be prudent for
pigeon health and to
prevent addition of a new vector of the virus in the
specific region. But a
worldwide ban on flying pigeons is not supported by
scientific information on
ecology of LPAI viruses
Thanks for bringing these misinterpretations to my attention
and I would hope
you would disseminate my response to other pigeon
veterinarians and fanciers.
Regards
David E. Swayne, DVM, PhD
Laboratory Director
Dr. Gordon Chalmers from Canada
Personal correspondence with Dr. Gordon Chalmers (Canada)
concerning AI problematic
If you examine the previous statement from Dr Swayne, you
will see that, even
though 60-80% of the inoculated birds did not become
infected, 20-40%
developed 'limited infections', so it seems that, yes,
pigeons can be infected at
times with AI viruses, in this case an H5N1 virus.
Dr Kaleta feels that H7 AI viruses seem to be able to infect
pigeons more
readily than H5 viruses.
With this information and the current problems in Europe and
Asia, I think it is
important for pigeon fanciers to be very careful for the
future, especially
because of the H5N1 virus now in Europe.
The Dutch authorities this summer showed the value of
isolating their poultry
flocks to protect them from contact with wild birds that
might be carrying
influenza viruses. We should learn from their experience and
isolate our pigeons
for the same reasons. This means no outside exercise, no
access to aviaries, no
loft visiting, no exchanges of birds, no visits to poultry
shows, and if necessary,
no racing either. Our birds can live to race another day!
Dr. Paul Miller from America
Part I
Personal correspondence with Dr. Paul Miller (USA)
concerning the AI problem
Hello Dr. Lanneau,
Thank you for your e-mail and attached literature survey.
I am currently attending the AAVLD convention, and the topic
is to be discussed
at length by the experts tomorrow. I briefly talked with one
of them, Dr. D. J.
King from Southeastern Poultry Lab in Athens, GA on
Saturday. He feels that
there is some variation between the H types, but that in
general, pigeons make
very poor hosts for AI. In some cases they can be infected
to the point that
they seroconvert, that is, the immune system 'sees' the AI
antigen, considers it
to be 'foreign' and responds. I will try to give you a more
detailed commentary
after the convention is over.
My personal view of all the AI publicity is that it is media
hype and pure fear
mongering. All the human deaths are in countries with very
poor sanitation and
hygiene standards, and abysmal medical infrastructure. The
fact is that, with
West Nile fading fast, the medical establishment needs a new
poster child, a
disease that will 'kill us all' if we don't give them
billions of $$$. The US
government is caving in to this nonsense with a $7.1B
control program to
forestall this phantom disease.
I will let you know what the pigeon aspect of this is after
the convention. Dr.
King told me that he has just submitted a draft of a new
paper he has written on
Newcastle in pigeons; it should be out in a few months,
probably in Avian
Diseases.
There was also some question about Adeno Virus in pigeons;
some feel that it is
an intestinal form of Circo. There has been some difficulty
identifying the
inclusion bodies in the intestine under Electron Microscopy
as true Adenovirus.
Sorry to be so brief. I'll try to be more complete later.
Hope all is well with you.
Kindest Regards,
Paul Miller
Dr. Paul Miller from America
Part II
Pigeons play a very minimal role in the entire Avian
Influenza scene. Up until
the emergence of the virulent H5N1 about a year ago, they
did not get H5 at
all. About a year ago, the H5N1 in Asia and Europe became
more virulent,
even pathogenic to its natural host, ducks, and this
virulent form can infect
pigeons to a limited degree. Dr. David Swayne from Athens,
GA gave a talk
yesterday at the AAVLD convention in which he presented this
information.
There is some variation among the H-types, but none go into
pigeons very
well, and pigeons do not transmit Avian Influenza well at
all.
This new pathogenic strain of H5N1 (in Europe and Asia) has
been put into
pigeons; it infects only a small percentage of the birds
exposed. It will even
kill a few. Pigeons are still very poor hosts for Avian
Influenza. For further
information, I would suggest that you contact Dr. David
Swayne directly at
the South Eastern Poultry Research Lab in Athens, GA.
Pigeons and poultry are as different as day and night. It is
obvious from the
Taxonomy: Galliformes and Columbiformes. From an Avian
Influenza point of
view, pigeons are different from any other bird: they just
do not host
Influenza well. Viruses in general are quite particular
about the cell type and
the cell surface that they will use for replication.
Apparently pigeons lack
the cell surface receptors and the cell physiology to
accommodate the
Influenza virus. It has to do with the cellular nature of
the bird. Even if you
take a pathogenic strain, such as the current Asian H5N1,
they still can not
be efficiently infected; only a few can be infected.
The basic situation here is this. The current hype about
Avian Influenza
mutating into a form highly contagious and fatal to humans
is nothing short of
fear mongering. Such an event is theoretically possible, but
highly
improbable, especially in the current state of medical
preparedness. All the
people who have died of Avian Influenza were in situations
of compromised
hygiene and sanitation with substandard medical care. Many
lived with their
chickens in the same house. Since the decline of West Nile
as a significant
health threat in the US, the medical bureaucracy has needed
a new ‘poster
child’, a menacing disease which will surely ‘kill us all’
if we don’t give them
billions of dollars. Avian Influenza fills that need, and
obviously the drug and
vaccine companies have jumped onto the band wagon. You would
have a
better chance of winning the lottery than you would of
getting Avian
Influenza; the chances are that slim.
At a meeting I was at yesterday at the AAVLD convention, I
asked a CDC
(Center for Disease Control) representative after a talk on
Avian Influenza
about the chances of any of this happening. She refused to
even discuss the
subject of what are the possibilities that this will
actually happen. All she
wanted to talk about is how horrendous things would be if it
actually did
happen: fear mongering, plain and simple. The CDC, WHO, OIE
and several
other medical bureaucracies obviously need more money, and
their ticket is
fear mongering some phantom Avian Influenza outbreak into a
full blown
crisis.
Dr. Colin Walker from Australia
Personal correspondence with Dr. Walker Colin (Australia)
concerning the AI problematic
Pascal,
As you say AI is very topical at the moment particularly in
Australia because of
our proximity to Indonesia and also because we did recently
have 3 pigeons in
quarantine test positive for AI antibodies. My understanding
of AI in pigeons is
that pigeons can catch AI but tend to be a rather resistant
species so that if
they do become infected the symptoms are fairly mild, they
quickly recover and
the carrier state does not occur.
Regards
Colin Walker, BVSc
Dr. Zsolt Talaber from Hungary
Personal correspondence with Dr. Zsolt Talaber (Hungary)
concerning the AI problematic
I think that pigeons can be infected with AI viruses. It
seems like the pigeons
have more resistance against the AI viruses as other bird
species, but at times
pigeons can catch this viruses and the illness can develop
in them. Moreover,
pigeons can spread the AI viruses mechanically, on their
plumage, feet etc
In case of AI we should say the pigeons are like as the
other bird species.
Theoretically ALL bird species can spread the AI viruses
mechanically, and a lot
of them can fall ill with avian influenza. So the answer:
pigeons must be
separated from other birds, but literally. Moreover, the AI
viruses are capable
of mutation, and a "successful" mutation of AI can be with
extraordinary
consequences in pigeons. The chance of it is bigger if
pigeons fall in with AI
viruses frequently.
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