Risk of the Introduction of High Pathogenic Avian Influenza

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					        Risk of the Introduction of High Pathogenic Avian Influenza (H5N1)
                          Into Ireland By Wild Birds – July 2007




Background
Following recent confirmation of the presence of H5N1 HPAI in the Czech Republic,
Germany and France and the publication of a comprehensive risk assessment by the
Department of the Environment, Food and Rural Affairs (Defra) of the likelihood of
the introduction of H5N1 HPAI into Great Britain by wild birds 1, the Department of
Agriculture, Fisheries and Food (DAFF) requested the National Parks and Wildlife
Service (NPWS) of the Department of the Environment, Heritage and Local
Government and BirdWatch Ireland to assess the risk posed to Ireland from
migratory birds from or passing through those affected parts of Europe.


DAFF wishes to express its appreciation for the ongoing support and ornithological
expertise provided by both the NPWS and BirdWatch Ireland.


Recent Developments in the EU
Following the cases of H5N1 HPAI in Hungary and England (Suffolk) in January and
February, respectively, the spring and early summer months were stable and no
further cases/outbreaks were reported in the European Union until an outbreak was
reported in a commercial turkey flock in the Czech Republic in June 2007.
Subsequent outbreaks were confirmed in the Czech Republic and in southern
Germany in June and in north-eastern France in July.


Since these initial outbreaks, there have been 5 cases in the Czech Republic, 296 in
Germany and 2 in France.             The most recently confirmed cases in the Czech
Republic, Germany and France were on 21 June, 18 July and 29 July, respectively.
The wild birds that have tested positive to H5N1 to date are Mallard Anas
platyrhynchos, Mute Swan Cygnus olor, Canada Goose Branta canadensis and
Black-necked Grebe Podiceps nigricollis.




1
  Defra (2007). Highly pathogenic avian influenza – H5N1: Recent developments in the EU and the
likelihood of the introduction into Great Britain by wild birds (Authors: Sabrovic, M., Hall, S.,
Wilesmith, J., Coulson, N.), 1A Page Street, London, SW1P 4PQ, United Kingdom. Version 1,
Released 12 July 2007.
Migratory Patterns
The months of July and August mark the period when the breeding season comes to
an end and the autumn migration commences for most bird species in the Canada,
Greenland and Iceland, and NW Europe flyways.          There are many factors that
determine when birds migrate or the rate at which particular elements of a population
will migrate as well as when or which routes they will take. Some of these factors
can be accounted for, such as weather effects, while others cannot, such as the
proportion that fails to breed and hence the extent and timing of any early migration
brought about by this failure to breed.


Some migratory waterbirds are known to arrive into Ireland as early as July, for
example Curlew Numenius arquata and Redshanks Tringa totanus.                  Curlew
Numenius arquata have been arriving at Irish coastal wetlands since early July along
with Redshank, Oystercatcher Haematopus ostralegus and Black-headed Gulls
Larus ridibundus. Some of these birds breed in Ireland and have simply moved from
their inland breeding sites to the coast, hence the numbers present in coastal
wetlands may comprise a combination of Irish-breeding as well as immigrant birds.


Some of the migratory species are on passage and use Ireland as a stop-over point
en route to southern Europe and Africa for the winter. Generally though, Ireland
tends to receive most birds from the north and north-west, i.e. Canada, Greenland
and Iceland, during the early autumn. Britain, however, receives birds from northern
Europe and further east to Siberia. Later in the autumn period – September/October
– migratory birds from northern Europe and further east will also arrive to Ireland to
winter here.


Assessment of Risk to Ireland
The report prepared by the NPWS and BirdWatch Ireland aimed to clarify, on the
basis of the information available, the risk posed to Ireland by the fifteen species
identified in the Defra report as posing some threat of introducing H5N1 to Britain. A
summary of the risk posed to Ireland by those species, describing the breeding
origins, wintering distributions and the numbers breeding (pairs, where appropriate)
and wintering (where appropriate) in Ireland, is set out in the accompanying table.
The table also includes a threat category ranging from highly unlikely to those
species that may be considered to pose the greatest threat.
The assessment of risk is based on a combination of the numbers expected to come
to Ireland over the coming months and the likelihood of them coming from currently
affected areas. This information on the known temporal occurrence of these species,
their numbers and breeding origins has been gathered largely from previously
published material.


Conclusion
Of the fifteen species listed in the Defra report, most are considered to pose little or
no risk of introducing H5N1 HPAI into Ireland at the present time and based on the
current situation elsewhere in Europe. Based on breeding origins and total numbers
expected to migrate to Ireland over the coming weeks, Northern Lapwings Vanellus
vanellus and Black-headed Gulls which, according to the Defra report, began to
arrive in Great Britain in July, might be expected to pose the greatest potential risk.
Both are likely to be distributed very widely in Ireland on both wetland and non-
wetland sites throughout the autumn and winter.


It is worth making the point that neither species have been implicated in the most
recent episodes in central and western Europe and have not, on the basis of the best
information available to the NPWS and BirdWatch Ireland, featured in previous
outbreaks    or   been   detected    through   EU-wide     surveillance   programmes.
Consequently, it is concluded that the risk to Ireland of the introduction of H5N1
HPAI through wild birds remains low at this early stage of the autumn migration.


In view of the early stage at which the migration season currently is and the
magnitude of the migration yet to come, particularly from late August onwards, the
situation will be kept under review and the risk reassessed, if appropriate, taking
account of the most up-to-date information available to DAFF, the NPWS and
BirdWatch Ireland.




Ends.

				
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