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Published Date: 2007-07-06 19:00:02
Subject: PRO/AH/EDR> Avian influenza (123): Review, Germany, France, wild birds
Archive Number: 20070706.2155

AVIAN INFLUENZA (123): REVIEW, GERMANY, FRANCE, WILD BIRDS
**********************************************************
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[1]
Date: Thu 5 Jul 2007
From: Justin Brown <jbrown@vet.uga.edu> [edited]

Re: Request for information on experimental infection trials in wild birds
-----------------------------------------------------
We would like to submit the following information in response to the
moderator's request for information on experimental infection trials
in wild avian species [included in archive 20070629.2090; 29 Jun
2007].
Further experimental infection studies are needed to evaluate the
susceptibility and the carrier efficiency of different wild avian
species infected with H5N1 HPAI virus. However, significant published
literature does exist on this topic.
Drs. Laura Perkins and David Swayne published, between 1999-2003,
several papers (listed below) on the pathobiology of H5N1 HPAI virus
in a wide variety of avian species including chickens, turkeys,
domestic ducks and geese, bobwhite and Japanese quail, chukar
partridges, ringed-neck pheasants, guinea fowl, budgerigars, European
starlings, house sparrows, laughing gulls, emus, and house and zebra
finches. These studies were conducted with a March 1997 isolate of
H5N1 HPAI isolated from chickens in Hong Kong and have been a
valuable resource on this topic.
More recently, we published a paper on the susceptibility of 5
non-domestic duck species (wood ducks, Northern Pintails, redheads,
blue-winged teal and mallards) and laughing gulls to an H5N1 HPAI
virus isolated from a dead whooper swan in 2005, and Klopfleisch et
al. (2006) reported the findings from pigeons experimentally infected
with another H5N1 virus (also listed below).
In addition, further studies have evaluated multiple recent H5N1 HPAI
virus infections in domestic waterfowl, such as Pekin ducks (_Anas
platyrhyncos_) (Pantin-Jackwood and Swayne, 2007) and American crows
and rock doves (Swayne, 2007).
We recently have completed an experimental infection study evaluating
the susceptibility of different swan and goose species to H5N1 HPAI
virus, which is currently being reviewed for publication. In this
study, we experimentally infected 4 species of swans and 2 species of
geese with H5N1 HPAI virus to evaluate their susceptibility, clinical
response, and viral shedding. The highest mortality rates were
observed in swans and species-related differences in clinical
response and viral shedding were evident. Based on our results, mute
swans, cackling geese, and bar-headed geese were identified as
waterfowl species that pose the greatest susceptibility to lethal
infection and some species shed virus for up to 4 days before
becoming ill. Such findings suggest some waterfowl species could
spread H5N1 HPAI virus between limited geographic regions, but
results do not suggest that these species would be long-term
reservoirs for this virus.
Though major gaps still exist in our understanding of H5N1 HPAI in
wild birds, good experimental data is in the literature which can
help us understand the transmission, susceptibility, and pathogenesis
of this virus in wild avian species.
References
Zhou JY, Shen HG, Chen HX, Tong GZ, Liao M, Yang HC, Liu JX.
Characterization of highly pathogenic H5N1 influenza virus derived
from bar-headed geese in China. Journal of General Virology 87:
1823-1833. 2006.
Sturm-Ramirez KM, Ellis T, Bousfield B, Bissett L, Dyrting K, Rehg
JE, Poon L, Guan Y, Peiris M, Webster RG. Reemerging H5N1 influenza
viruses in Hong Kong in 2002 are highly pathogenic to ducks. Journal
of Virology 78: 4892-4901. 2004.
Hulse-Post DJ, Sturm-Ramirez KM, Humberd J, Seiler P, Govorkova EA,
Krauss S, Scholtissek C, Puthavathana P, Buranathai C, Nguyen TD,
Long HT, Naipospos TS, Chen H, Ellis TM, Guan, Y, Peiris JS, Webster
RG. Role of domestic ducks in the propagation and biological
evolution of highly pathogenic H5N1 influenza viruses in Asia.
Proceedings of the National Academy of Sciences of the United States
of America 102: 10682-10687. 2005.
Pantin-Jackwood MJ, Swayne DE. Pathobiology of Asian highly
pathogenic avian influenza H5N1 virus infection in ducks. Avian
Diseases 51: 250-259. 2007.
Perkins LEL, Swayne DE. Pathobiology of A/chicken/Hong Kong/220/97
(H5N1) avian influenza virus in seven gallinaceous species.
Veterinary Pathology 38: 149-164. 2001.
Perkins LEL, Swayne DE. Pathogenicity of a Hong Kong-origin H5N1
highly pathogenic avian influenza virus for emus, geese, ducks, and
pigeons. Avian Diseases 46: 53-63. 2002.
Perkins LE, Swayne DE. Comparative susceptibility of selected avian
and mammalian species to a Hong Kong-origin H5N1 high-pathogenicity
avian influenza virus. Avian Diseases 47: 956-967. 2003.
Perkins LE, Swayne DE. Varied pathogenicity of Hong Kong-origin H5N1
avian influenza virus in four passerine species and budgerigars.
Veterinary Pathology 40: 14-24. 2003.
Brown JD, Stallknecht DE, Beck JR, Suarez DL, Swayne, DE.
Susceptibility of North American Ducks and Gulls to H5N1 Highly
Pathogenic Avian Influenza Viruses. Emerging Infectious Diseases 12:
1663-1670. 2006.
Klopfleisch R, Werner O, Mundt E, Harder T, Teifke JP. Neurotropism
of highly pathogenic avian influenza virus A/Chicken/Indonesia/2003
(H5N1) in experimentally infected pigeons (Columbia livia f.
domestica). Veterinary Pathology 43: 463-470. 2006.
Swayne DE. Understanding the complex pathobiology of high
pathogenicity avian influenza viruses in birds. Avian Diseases 51:
242-249. 2007.
--
Justin Brown and David Stallknecht
Southeastern Cooperative Wildlife Disease Study
University of Georgia
Athens, Georgia, USA
<jbrown@vet.uga.edu>
David E. Swayne
Southeast Poultry Research Laboratory
Agricultural Research Service
U.S. Department of Agriculture
Athens, Georgia, USA

[The above firsthand, updated information and references of
multi-disciplinary research, received from leading experts, is
impressive, encouraging and very much appreciated.
The recent, yet-to-be-published study, is of particular interest.
According to the authors, the study's results indicate the following:
"Mute swans, cackling geese and bar-headed geese were identified as
waterfowl species that pose the greatest susceptibility to lethal
infection and some species shed virus for up to 4 days before
becoming ill. Such findings suggest some waterfowl species could
spread H5N1 HPAI virus between limited geographic regions, but
results do not suggest that these species would be long-term
reservoirs for this virus".
The distances such infected waterfowl could fly within up-to 4
pre-clinical days are considerable and should be kept in mind.
The species which would be long-term H5N1 HPAI reservoires,
supposedly by undergoing viraemia (of extended duration?) without
becoming ill, remains to be further investigated. As the authors
rightly say, further experimental infection studies are needed to
evaluate the susceptibility and the carrier efficiency of different
wild avian species infected with H5N1 HPAI virus.
Information on such investigations, and any results becoming
available, will be welcomed. - Mod.AS]
******
[2]
Date: Thu 5 Jul 2007
Source: Eurosurveillance weekly releases, Vol 12, Issue 7 [edited]
<http://www.eurosurveillance.org/ew/2007/070705.asp#0>

Highly pathogenic avian influenza A/H5N1 in birds within the EU -
Implications for Public Health
---------------------------------------------------------------------
Since the later part of June 2007, 3 European Union (EU) Member
States (Czech Republic, Germany, and France) have recorded cases of
highly pathogenic avian influenza (HPAI) of the subtype A/H5N1 in
bird populations.
On 21 Jun 2007, authorities in the Czech Republic confirmed an
outbreak of HPAI A/H5N1 in a domestic poultry flock in the Pardubicky
region in the centre of the country [1] [For the said reference 1 and
the others mentioned in the article, subscribers are referred to the
URL above. - Mod. AS]. A few days later a 2nd infected flock, located
4 km [2.48 miles] from the first, was identified through the enhanced
surveillance of flocks in the area that was introduced after
discovery of the first infected premise [2]. Subsequently, virus was
isolated from a wild bird (swan) found dead on 28 Jun 2007 in the
Jihomoravsky region in south of the country, near the border to
Austria [3].
At almost the same time, on 26 and 28 Jun 2007, German authorities
reported that HPAI A/H5N1 had been identified in wild birds in 2
locations in Germany; six wild birds (5 swans and one Canada goose)
in Bavaria in southern Germany [4], and 3 wild swans in Saxony in
eastern Germany [5].
On 5 Jul 2007, France also confirmed the first occurrence this year
of 3 wild swans infected with influenza A/H5N1. They were found in
the Mosel region in the north-east of France [6].
Samples from the infected birds from all 3 countries were identified
as part of the EU supported active surveillance programme for avian
influenza in wild birds, which requires all EU Member States to test
wild birds for avian influenza viruses in order to provide an early
warning of the presence of the virus in the EU [7].
Virus strain analysis
---------------------
Initial phylogenetic analysis of the virus subtype from the
outbreaks, conducted by the EU's Community Reference Laboratory for
Avian influenza in the United Kingdom (UK) and the Friedrich-Loeffler
Institut in Germany, suggests that the viruses recently identified in
the Czech Republic and Germany are highly similar. However, they are
of different origin from those identified during other EU poultry
outbreaks earlier this year (UK and Hungary) and in 2006. Instead,
the current virus is more closely related to a lineage originating
from the Middle East (including Bangladesh, Pakistan and Azerbaijan)
and Russia [8]. However, as for all H5N1 viruses to date, there has
been no indication of a significant phylogenetic change which would
alter the behaviour of the A/H5N1 virus in humans.
Control measures in animals
---------------------------
In accordance with EU animal health legislation prompt and vigorous
animal disease control measures have been taken in both countries.
Understandably, measures are more stringent for outbreaks in domestic
poultry where the onus is to remove the source of infection, and to
dampen down or stamp out the level of virus in the vicinity as
quickly as possible so as to prevent spread. In this case legislation
dictates a containment strategy involving culling all birds on the
affected premises followed by cleaning and disinfection. In addition,
2 roughly concentric zones must be established around the affected
farms: A 3-km [1.86 miles] protection zone and a 10-km [6.21 miles]
surveillance zone, which constitute Area A (high risk), and a
surrounding buffer zone called area B (lower risk) [9].
If A/H5N1 is discovered in wild birds, EU legislation allows a less
stringent approach but still requires that a control area and a
surrounding monitoring area are established around the infected
birds. This can be adapted on a case by case basis following a risk
assessment taking into account the local geographical, ecological and
epidemiological circumstances. Measures are aimed at preventing the
spread of avian influenza from wild birds to poultry or other captive
birds and include strengthening of on-farm biosecurity and disease
awareness, temporary banning of wild bird hunting and restrictions on
the movement of poultry and poultry products [10].
Epidemiological investigations as to the possible source of the
domestic poultry outbreaks in the Czech Republic are ongoing. No
cases of influenza A/H5N1 have been recorded in wild birds in the
vicinity of any of the domestic poultry cases in 2007 (the case of
A/H5N1 reported in a wild bird in the Czech Republic was over 150km
to the south of the infected farms). However, the fact that the
outbreaks in domestic poultry coincided with the first reports of
cases in wild birds in the EU in 2007 is probably more than a
coincidence. It may indicate that the virus remains present
intermittently in wild bird populations within some Member States.
This also places domestic poultry flocks at risk. The high genetic
similarity of the strain in wild and domestic birds in the current
outbreaks is at least consistent with interaction between wild birds
and domestic poultry [8].
General implications
--------------------
The re-emergence of influenza A/H5N1 in EU bird populations is of
concern, but not an unexpected development since A/H5N1 viruses are
highly persistent across the world. In some countries (all outside
Europe) the viruses are now endemic. However, in other areas like the
European Member States, they are appearing intermittently through
uncontrollable movements of wild birds and perhaps also illicit or
poorly controlled poultry trading [11]. The fact that active
surveillance has been underway throughout the EU since 2002, and was
increased in 2006 and 2007, and the fact that the cases described
were the first isolations of A/H5N1 in wild birds this year, suggest
that infection is neither as widespread nor as intense as in the
early spring of 2006. However, the cases in wild birds are a timely
reminder to all Member States to continue veterinary surveillance
activities in bird populations (wild and domestic). This provides an
essential early warning of the presence of the virus. If it is found
in birds, it is vital that containment measures are rapidly deployed
to control infection to prevent the virus from becoming established
in domestic poultry. This is important in order to preserve the
health of animals, and also to minimise the risk of human exposure to
the virus.
Public health implications
--------------------------
Wherever cases of avian influenza are suspected, close collaboration
between public health specialists and veterinarians remains crucial.
This is especially the case for A/H5N1 because, although the virus is
predominantly an infection in animals, and to date it has proved very
difficult to transmit from birds to man, it has a high case fatality
rate in those humans that become infected [11]. The aim is to ensure
that people that have close contact with infected birds are given
appropriate levels of advice and support. Because the recent incident
in the Czech Republic involved outbreaks in domestic poultry, with
large numbers of potentially infected animals requiring culling to
minimise the spread of infection, public health authorities have been
actively involved in:
- providing advice to workers involved in the culling operations on
the use of personal protective equipment (e.g. masks and gloves);
- providing advice on the use of prophylactic antiviral drugs; and
- following up exposed workers.
The cases in Germany occurred in individual wild birds and hence the
risk of potential human exposure was much lower than in cases
involving infected domestic poultry. However, there has been a
cluster of human cases associated with slaughtering and plucking of
feathers from wild birds that were suspected to have been infected
with A/H5N1 (swans in Azerbaijan). This indicates that there is
potential human health risk from wild birds, although it is likely to
be low, and very dependant on how birds are handled and the
precautions taken (12). It is however important that general
precautions messages are communicated to the population to avoid
handling birds found dead, and, as demonstrated in Germany, that
authorities engage with those individuals that may have handled
infected wild birds to advise them of how to protect themselves, the
need to monitor their health, and provide advice and reassurance as
necessary, along with antiviral prophylaxis if considered necessary.
The recent outbreak of low pathogenicity avian influenza A/H7N2 in
the UK has shown how people with home and hobby flocks can easily be
infected if they are unaware of the risk [14].
Since the autumn of 2005, ECDC has been producing technical
guidelines for minimising the risk of humans acquiring avian
influenza (specifically H5N1) from exposure to infected birds or
animals. A portfolio of guidance documents and risk assessments on
other public health aspects of A/H5N1 is available for public health
authorities and the public [15]. These documents highlight the
importance of removing the source of infection as quickly as
possible, while also implementing risk-minimising public health
measures. ECDC has also produced a more general risk assessment of
the public health risk posed by highly pathogenic avian influenza
viruses emerging in Europe, with specific reference to type A/H5N1
[12].
Pandemic Risk
-------------
The 3 pandemics of the 20th century all had their origins to varying
extents in genetic material introduced from avian into human
influenza viruses, with the virus that caused the 1918 Spanish
Influenza being the one most closely related to an avian strain [16].
There is no prima facie reason why the genes in A/H5N1 should
contribute to the next pandemic rather than other avian influenzas
(H2, H7, H9, etc.) that are currently circulating. What makes
scientists and public health officials more nervous about A/H5N1 is
its unprecedented mortality rate in humans of over 60 percent. Unlike
most other avian influenza viruses it is exceptionally persistent in
birds and keeps coming into contact with humans in countries where it
is endemic in domestic birds [11,12]. Therefore the EU is sensibly
preparing for any influenza pandemic, while watching influenza A/H5
viruses in particular [17].
Conclusions
-----------
Influenza A/H5N1 viruses remain 'a group of influenza viruses of
birds, poorly adapted to humans whom they find hard to infect except
at high doses. They are dangerous as they are highly pathogenic in
those few humans that do become infected, but then they generally do
not transmit on to other humans' [11]. This, together with veterinary
measures and application of public health guidelines, is probably the
reason why, to date, influenza A/H5N1 infection in wild and domestic
birds in Europe has not resulted in human infections. However, there
is no room for complacency. Ongoing vigilance, control of infection
in poultry, communication to those at risk, and prompt response (case
finding and management) to human cases remain the cornerstones of
protecting humans against A/H5N1 viruses.
[Byline: Influenza Team
European Centre for Disease Prevention and Control, Stockholm, Sweden
<Influenza@ecdc.europa.eu>]
[The web site of ECDPC's influenza team is available at
<http://www.ecdc.europa.eu/About_us/projects/influenza.html>. - Mod.AS]
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
******
[3]
Date: Fri 6 Jul 2007
Source: Deutche Welle [edited]
<http://www.dw-world.de/dw/article/0,2144,2671360,00.html>

Germany, France Raise Bird Flu Risk Level After New H5N1 Cases
--------------------------------------------------------------
Germany's top state veterinary laboratory raised the risk level after
more wild birds had tested positive for H5N1 in the eastern states of
Saxony-Anhalt and Thuringia.
"We will raise the threat level," a spokeswoman for the Friedrich
Loffler Institute told reporters.
The regional authorities in Sangerhausen in Saxony-Anhalt reported
that 38 dead birds found on the shores of an artificial lake near the
town of Kelbra had all tested positive. Saxony-Anhalt is the 4th of
Germany's 16 states to report cases of H5N1 bird flu since late last
month [June 2007], when it struck down 6 wild birds in the southern
city of Nuremberg in Bavaria.
On Tue 3 Jul 2007 a bird found on the other side of the lake which is
in Thuringia was confirmed to have had H5N1 bird flu. Cases have also
been reported near Leipzig in the neighboring eastern state of
Saxony, bordering the Czech Republic which is battling a more severe
outbreak of the H5N1 avian flu.
The Friedrich Loffler Institute suggested the disease could have
jumped the border from the Czech side where it has infected turkey
and chicken farms. So far in Germany the new outbreak has been
restricted to swans, geese and other wild birds and has not affected
poultry farms.
Germany battled a widespread bird flu epidemic in 2006. It broke out
on the Baltic Sea island of Rugen and spread to 6 states, including
Bavaria. The disease spread to mammals, infecting 3 cats and a stone
marten, but did not affect humans.
In neighboring France, Europe's biggest poultry producer, authorities
stepped up surveillance after tests on 3 dead swans confirmed an H5N1
outbreak. Agriculture Minister Michel Barnier raised the threat level
from bird flu from "moderate" to "high" following the test results on
the swans that were found dead in northeast France last week. It is
France's second outbreak of the deadly strain of bird flu in 17
months, but Health Minister Roselyne Bachelot said there was no
reason for alarm. "France is not threatened by a bird flu pandemic as
there has not been, for the moment, a human contamination from the
H5N1 virus," Bachelot said. But she added "we must be vigilant as the
great flu epidemic that followed the war of 1914, the Spanish flu"
came from a strain of bird flu.
Scientists believe a strain related to today's bird flu virus caused
the death of tens of millions of people during the Spanish flu
pandemic.
"We must do what is necessary to ensure that all of the agencies, the
entire health system is ready to deal with a mutation of the virus"
that could attack humans, said Bachelot on French television.
Fresh measures were ordered to ensure that chickens and other poultry
did not enter into contact with wild birds and that they underwent
monthly veterinary checks. Pigeon competitions have been banned and
security around a one-km (0.6 mile) exclusion zone established around
the pond in the Moselle department where the dead swans were
discovered has been beefed up.
A second 15-km [9.32 miles] "observation" zone was set up around the
pond at Assenoncourt but a spokesman for the local municipality said
no other dead birds had been found there, which he described as a
"reassuring" sign.
"These measures apply to all farms that must be protected from wild
birds that fly overhead. These protective measures are nets and a ban
on bringing birds together in public places and at markets," Barnier
said.
Officials put 3 farms in the observation zone under quarantine, and
restricted access to roads in the area.
"With these measures that we are taking, the risk of contamination
will be very small," said Philippe Hestroffer, of the regional
veterinary services.
A first outbreak of H5N1 in February 2006 was detected in 62 dead
birds in central France and spread to a farm near the town of
Versailleux where hundreds of turkeys were slaughtered. It was also
the first outbreak of the virulent strain in the European Union.
France produces 900 million poultry per year including 700 million
chickens, according to the Confederation of French Poultry Producers.
The sector employs 80 000 people and generated 4 billion euros (USD
5.4 billion) last year.
In the Netherlands, the authorities ordered all poultry to be kept
inside. They announced the measure after what they called the
discovery of a bird flu case "not far from the Netherlands."
While the bird flu virus is highly contagious among poultry and can
spread to an entire flock, it remains difficult for humans to catch.
A total of 191 people worldwide have died of bird flu, according to
the World Health Organization [WHO], which has reported 317 cases in
its 29 Jun 2007 tally. Indonesia, Vietnam and Thailand top the list
of most-affected countries.
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[A graph showing the number of Avian Influenza (subtype H5N1)
outbreaks in poultry, reported to the OIE from the end of 2003 to 05
July 2007 by 43 countries, is available at:
<http://oie.int/downld/AVIAN%20INFLUENZA/Graph%20HPAI/graphs%20HPAI%2005_07_2007.pdf>.
Cases in wild birds are not included.
More information on avian influenza in wild birds is available in
ProMED-mail's thread "Avian influenza, poultry vs migratory birds." -
Mod.AS]

See Also