AVIAN INFLUENZA IN WILD BIRDS IN PUBLIC PARKS AND AQUATIC
AMENITY AREAS IN IRELAND:
A RISK ASSESSMENT.
October 2006
1. Background:
Avian influenza is a disease of birds caused by an avian influenza A virus of which about
16 different types have been identified based on the structure of their surface attachment
protein. Most of these viruses cause either no clinical disease, or only mild symptoms in
the infected birds and are called Low Pathogenic Avian Influenza (LPAI). These LPAI
strains are not unusual in waterfowl (ducks, swans and geese) around the world.
However, a characteristic of the influenza virus family is their ability to mutate rapidly
and for new strains to appear. Some of the mutants have the ability to cause more severe
disease and they are then called Highly Pathogenic Avian Influenza (HPAI). In this
manner the highly pathogenic H5N1 strain arose in Southeast Asia and has resulted in the
current (2003-2006) epidemic affecting poultry, wild birds and rarely people or other
mammals such as cats, dogs, and various wild carnivores.
The role of wild birds, and particularly waterfowl, in maintaining LPAI is well
documented and once introduced into domestic poultry the LPAI strains can also mutate
into HPAI. The question now is what role migratory waterfowl play in the spread of
HPAI H5N1 in the current epidemic? The recent emergence of the Asian lineage of
H5N1 in western Europe shows that long distance spread has occurred but further
research is needed to determine how this has occurred. Migration of waterfowl from Asia
and eastern Europe during a period of unusually cold winter weather in early 2006 was
undoubtedly a significant risk factor. HPAI H5N1 first appeared in the EU in February
2006 when the virus was found in over-wintering waterfowl including ducks and mute
swans (Cygnus olor). The closest known occurrence of HPAI H5N1 to Ireland was the
discovery of a dead whooper swan (Cygnus cygnus) found on the Fifeshire coast in
Scotland in March.
A previous risk assessment exercise conducted by DAF in collaboration with NPWS and
BirdWatch Ireland has identified 24 species of water birds that pose the greatest risk of
introducing avian influenza into Ireland, or spreading it once it has arrived. These include
two species of swan, two species of geese, 10 species of ducks, two of rails, three of
waders, and five of gulls (Table 1 & Fig. 1). A further four species of water birds (two
grebes, brent geese, and the cormorant) pose a lesser risk. The risk assessment was based
on the following criteria:
 Migration from areas known to have HPAI H5N1.
 Previously known to have been infected by H5N1 in other countries.
 Known use of farmland as well as wetland habitats.
 Species that are gregarious and have the potential to spread viruses.
 Proximity of their natural habitat to areas of poultry farming.
Should HPAI H5N1 arrive in Ireland with migratory waterfowl during the coming winter
season (2006/07) it could appear at any wintering site used by these birds. The
distribution of wetland habitat in Ireland encompasses the coastal estuaries and bays and
also inland lakes, callows, rivers, and bogs (Fig. 2). Because of the pattern of
demographic settlement and land use in Ireland, none of these areas are remote from
human settlement, farming, or amenity areas used for boating, fishing, hunting,
swimming, or other pursuits that could bring people or domestic animals into contact
with birds, bird droppings, carcases or other potential sources of influenza virus.
2. Issues
The purpose of this risk assessment is to describe the qualitative risk from avian influenza
from water birds posed to members of the public using aquatic/wetland amenity areas or
parkland also used by water birds. It also describes the risk to park workers, to staff of
the NPWS, DAF, Local Authorities, Civil Defence, and to members of volunteer
organizations such as BirdWatch Ireland who may be exposed to wild waterfowl, given:
 The current distribution of avian influenza in Europe.
 The epidemiology of virus spread and potential pathways that may present a risk
to humans.
 Our understanding of the environmental survival of the virus once excreted from
an infected host.
 The zoonotic potential and virulence of the virus.
3. Risk Assessment
In the six month period from May to October 2006 there have been 20 occurrences of
HPAI H5N1 in wild birds in EU member states and 18 of those were in May at the tail
end of the Winter / Spring incursion of the virus from the east. Since then there was one
case of infection in a free-living great crested grebe in northern Spain in June and a single
case in a captive swan in Dresden Zoo in August. Further afield the incidence of
infection in wild birds has been equally unremarkable with a limited number of outbreaks
in waterfowl in Siberia between June and September. The most recent outbreak occurred
in the Omsk region of Russia in early September. At the present time in mid-October the
autumn migration is well underway and peak numbers of wintering water birds should
arrive in Ireland in the coming weeks. The current risk of HPAI H5N1 incursion is
minimal but this situation could change with the arrival of birds from the east. It would
be unlikely that avian influenza would appear in Ireland without first being detected in
another EU member state.
Should HPAI H5N1 arrive in Ireland with returning migratory water birds, the main
mechanism by which it could spread to other birds would be by faecal or respiratory
excretion. For transmission to other animals and humans, ingestion of faeces or food
contaminated by infected bird faeces is a more likely route. Thus, for a person to be
infected, they must ingest food or water contaminated by the faeces of an infected bird, or
have such material come in close contact with sensitive areas such as the conjunctivae of
the eye in sufficient quantity. When water birds defecate, the faeces are semi-liquid and
any viral particles are bound to the organic matter in the faeces. This is not particularly
hazardous unless foodstuff is contaminated. The infective dose of virus will also
decrease rapidly as the faeces dries out and is exposed to UV rays in sunlight, rain, wind
and other environmental elements. In addition, viruses cannot multiply outside a host
animal - further reducing the quantity that could infect a new host. Therefore in a
situation where water birds are living in natural habitat, it is highly unlikely that humans
would be exposed to an infective dose by ingestion or by dried viral particles blowing
into eyes, mouth or airways. Such mechanisms of transmission are only likely under
circumstances of intensive poultry production where large numbers of infected birds are
housed indoors generating large quantities of infected aerosol.
Infected waterfowl excreting large quantities of virus into water bodies such as ponds,
lakes, canals, reservoirs, or outdoor swimming pools could pose a theoretical risk to
humans using these amenities. The risk is less where dilution results from greater water
volumes or higher flow rates. The avian influenza virus is also sensitive to the elements
and its survival is dependant on water temperature, water chemistry (pH, salinity), and
exposure to the sterilizing effects of UV light all of which will deactivate the virus.
Increasing temperature increases the rate of deactivation, with the virus being most stable
between 4oC and 10oC. It can remain infectious for at least a month at 0oC but only six
days at 37oC. So under Irish winter conditions it could survive in the environment for
periods of hours to several weeks. It can also remain infectious for longer in fresh water
habitats than in brackish estuarine or marine habitats.
The H5N1 strain of avian influenza is transmissible to people but it is poorly adapted to
human hosts with only 256 people confirmed with infection worldwide since 2003.
Approximately half of these have died as a result. Most of those who were infected had
very close contact with infected poultry and were involved in slaughtering infected birds,
plucking or dressing carcasses, had infected birds in their dwelling or allowed children to
play with sick or dead birds. There is only one example of human infection from wild
birds and that occurred in Azerbaijan when people plucked swans that had died from
H5N1 infection.
No cases have been found in people involved in any of the following activities:
 Culling infected poultry in commercial units throughout SE Asia.
 Conducting survey work on poultry or wild birds.
 Ornithological research such as bird banding or ringing.
 Husbandry of birds in zoos or parks.
 Refuse collectors including those involved in clean up after culling of flocks.
 Veterinary work and poultry farm workers.
 Wildlife rehabilitation.
4. Conclusions
Based on current scientific research and thinking with regard to avian influenza it
may be concluded that:
 The risk of infection in people, and particularly from wild birds, is very low
for the circulating H5N1 strain of HPAI.
 The most likely means of introduction of this virus to areas of public use such
as parks and recreational waterways (rivers, lakes and beaches) is through
faeces of infected waterfowl.
 In respect to public use of parks and parklands, direct contact with fresh
bird faeces should be avoided. Contamination of skin or clothing should be
washed off with soap and water. Disinfectants are not required as the
influenza virus is sensitive to detergents alone. Likewise, the virus is sensitive
to UV light, and degradation will occur with exposure to the elements such as
wind, rain, and sunlight.
 Dogs and cats are also unlikely to be infected in parks or parklands barring
scavenging of dead birds or consumption of large quantities of recentlyexcreted infected faeces.
 Recreational activities such as boating, fishing, canoeing, water skiing or
swimming would entail minimal risk of people contracting avian influenza.
Wild waterfowl are unlikely to be present in significant numbers where
many of these activities occur, and persons involved are not likely to ingest
any or sufficient quantities of infected material.
 The dilution capacity of the water body is also likely to dilute any infected
material rapidly to a level where it is no longer infectious. As mentioned
above, exposure to sunlight and other adverse environmental conditions will
also inactivate the virus.
 Small water bodies such as ponds or small shallow lakes with a high density
of water birds and heavy faecal contamination of the water should be
avoided for the recreational activities mentioned if that use entails a risk of
ingesting contaminated water.
5. Recommendations
With the current distribution of HPAI H5N1 globally and current understanding of the
epidemiology of infection it is recommended there is minimal risk to the public or their
pets in normal use of parks, parklands for recreational purposes. Therefore:
1) There should be no restrictions on use of these areas.
2) Aquatic activities such as swimming, canoeing, boating, skiing etc in water bodies
where there is ample dilution of faeces from birds entails minimal or no risk to the
public. Such activities are only a risk in small water bodies heavily contaminated
by faecal matter from infected birds. Such areas should not be used for these
activities regardless of whether avian influenza is present or not.
3) The advice on the Department of Agriculture and Food website:
http://www.agriculture.gov.ie on the handling of dead birds and their safe disposal
is appropriate and current.
4) The advice to staff who may be exposed to wild birds through their occupation in
regards to personal hygiene, proper use of personal protective equipment (PPE),
and categorization of risk is also in concurrence with scientific thinking:
http://www.agriculture.gov.ie.
5.1. These conclusions may be validated by assessment of risk in the following
scenarios:
 Scenario 1: There is no evidence of HPAI H5H1 in Ireland.
 Scenario 2: HPAI H5N1 infection confirmed in a single migratory water
bird in a park used for recreational purposes in Ireland.
 Scenario 3: HPAI H5N1 detected in an endemic wild bird in a park in
Ireland.
 Scenario 4: A local die-off of endemic wild birds has occurred in a park
and HPAI H5N1 is suspected.
 Scenario 5: A local die-off of endemic wild birds has occurred in a park
and HPAI H5N1 is confirmed.
5.1a. Scenario 1, HPAI H5N1 is not in Ireland:
 There is no risk to the public using parks or waterways for recreational purposes.
 Likewise, there is no risk to employees of the parks and wildlife service or local
authorities who may come in contact with wild birds inhabiting these areas.
 General hygiene standards should still be maintained to protect against any
zoonoses that could be contracted from contact with wild bird faeces.
 Dead birds should be handled as per the DAF guidelines.
 Areas with hard surfaces where waterfowl may aggregate and be fed by the public
should be kept as clean as possible by regular washing down to decrease the
faecal load. Detergents or viricides are not necessary.
 Normal public use of aquatic recreational areas should not be restricted.
5.1b. Scenario 2, HPAI H5N1 found in a single migratory bird in Ireland:
 DAF may place restrictions around the area in which the bird was found as per
Commission Decision 2006/563/EC.
 Restricted areas will be demarcated by an Avian Influenza Infected Zone notice
(Fig. 3).
 Risk analysis will also be conducted by DAF, assisted by NPWS, to determine the
size of the restricted areas, or the need for such restricted areas, and whether
infection has spread to other birds.
 While restrictions are in place, certain recreational activities such as game hunting
will be prohibited.
 Parks and aquatic recreational areas should remain open for normal use by the
public but parks should have signage for public toilets or washrooms where soap
and running water is available for hand washing.
 Dead birds should be handled as per the DAF guidelines.
 Areas with hard surfaces where waterfowl may aggregate and be fed by the public
should be kept as clean as possible by regular washing down to decrease the
faecal load. Detergents or viricides are not necessary.
5.1c. Scenario 3, transmission of HPAI H5N1 has occurred to a native wild bird in a
local area such as a park:
 DAF will impose restrictions as per Commission Decision 2006/563/EC until
further investigations have determined the cause of the event.




Restricted areas will be demarcated by an Avian Influenza Infected Zone notice
(Fig. 3).
While restrictions are in place, certain recreational activities such as game hunting
will be prohibited. However, parks and aquatic recreational areas should remain
open for normal use by the public because the risk of transmission to the public
and to their pets would remain unchanged. Parks should have signage for public
toilets or washrooms where soap and running water is available for hand washing.
There should be increased vigilance by park staff for dead birds and these should
be handled as per the DAF guidelines and removed promptly for diagnostic
purposes or disposal. DAF should be notified of all sick or dead birds via the
Local Disease Control Centre (LDCC) or the Avian Influenza Helpline (1890 252
283).
Areas with hard surfaces where waterfowl may aggregate and be fed by the public
should be kept as clean as possible by regular washing down to decrease the
faecal load. Detergents or viricides are not necessary.
5.1d. Scenario 4, HPAI H5N1 is suspected as the cause of a local die-off of endemic
birds.
 DAF will impose restrictions as above and further risk assessment initiated with
the assistance of NPWS.
 Restricted areas will be demarcated by an Avian Influenza Infected Zone notice
(Fig. 3).
 Increased surveillance should be carried out by DAF and NPWS staff to retrieve
all dead birds for analysis or disposal as per DAF guidelines.
 All sick and dead birds should be reported to the LDCC or to the Avian Influenza
Helpline.
 The public should be warned not to handle dead birds and signage posted showing
the Avian Influenza Helpline number.
 There is no risk to members of the public who witnessed the die off without direct
contact with affected birds.
 The public should be restricted from the immediate area of the die off until dead
birds are removed and any hard surfaces washed down with running water. There
would not be any need to use detergents or viricides on these areas. Daily
cleaning with water and sweeping should be sufficient to maintain these areas
subsequently.
 Regular surveillance for moribund or dead birds should continue after the event to
provide public reassurance and to remove any carcasses from the area. Otherwise
public access and use of the park should continue as normal.
5.1e. Scenario 5, HPAI H5N1 has been confirmed as the cause of a local die-off of
wild birds.
 In this case all of the measures necessary to control and eradicate infection would
have been carried out while infection was suspected. Thus there would be no
incremental risk to the public by confirmation of H5N1.
 Increased surveillance should be carried out by DAF and NPWS staff to retrieve
all dead birds for analysis or disposal as per DAF guidelines.





All sick and dead birds should be reported to the LDCC or to the Avian Influenza
Helpline.
The public should be warned not to handle dead birds and signage posted showing
the Avian Influenza Helpline number.
There is no risk to members of the public who witnessed the die off without direct
contact with affected birds.
The public should be restricted from the immediate area of the die off until dead
birds are removed and any hard surfaces washed down with running water. There
would not be any need to use detergents or viricides on these areas. Daily
cleaning with water and sweeping should be sufficient to maintain these areas
subsequently. If regular cleaning cannot be conducted of areas heavily
contaminated by waterfowl faeces, then restricted access to these areas should be
considered.
Regular surveillance for moribund or dead birds should continue after the event to
provide public reassurance and to remove any carcasses from the area. Otherwise
public access and use of the park should continue as normal.
References
1) DAF website: http://www.agriculture.gov.ie/ (Advice on handling dead birds,
Occupational health Guidance for Avian Influenza.
2) Aznar, I., More, S., McGrath, G., Collins, D., Crowe, O. 2006. An assessment of
the risk of the introduction and spread of avian influenza in Ireland relating to the
activities of migratory waterbirds. CVERA and BirdWatch Ireland.
3) World Health Organization website: http://www.who
4) European Commission, Animal Disease Notification System webpage:
http://ec.europa.eu/food/animal/diseases/adns/index_en.htm
5) OIE webpage: http://www.oie.int/eng/en_index.htm
6) ProMed website: http://www.promedmail.org
7) DEFRA website: http://www.defra.gov.uk/
8) FAO website: http://www.fao.org/.
9) Pfeiffer, D.U. et al., 2006. Scientific Opinion on Migratory Birds and their
possible role in the spread of Highly Pathogenic Avian Influenza. The EFSA
Journal 357, 1-46.
Table 1. WILD BIRDS THAT POSE THE GREATEST RISK FOR AVIAN INFLUENZA IN IRELAND
COMMON NAME
SPECIES
TYPE
STATUS IN IRELAND
HABITAT
AI RISK
Mute swan
Cygnus olor
Swan
Resident
Freshwater & coast
High
Whooper swan
Cygnus cygnus
Swan
Winter immigrant
Freshwater & coast
High
Greylag goose
Anser anser
Goose
Resident & winter immigrant
Estuaries,freshwater & arable land
High
Canada goose
Branta canadensis
Goose
Resident
Freshwater, estuary, arable land
High
Shelduck
Tadorna tadorna
Dabbling duck
Resident, moult & winter immigrant
Estuaries
High
Wigeon
Anas penelope
Dabbling duck
Winter immigrant
Freshwater & estuaries
High
Gadwall
Anas strepera
Dabbling duck
Breeding & winter immigrant
Freshwater & coast
High
Teal
Anas crecca
Dabbling duck
Breeding & winter immigrant
Freshwater & coast
High
Mallard
Anas platyrhynchos
Dabbling duck
Resident & winter immigrant
Freshwater & coast
High
Pintail
Anas acuta
Dabbling duck
Winter immigrant
Freshwater & coast
High
Shoveler
Anas clypeata
Dabbling duck
Resident & winter immigrant
Freshwater & coast
High
Pochard
Aythya ferina
Diving duck
Winter immigrant (some resident)
Freshwater
High
Tufted duck
Aythya fuligula
Diving duck
Breeding & winter immigrant
Freshwater
High
Goldeneye
Bucephala clangula
Diving duck
Winter immigrant
Freshwater & coast
High
Coot
Fulica atra
Rail
Breeding & winter immigrant
Freshwater & estuaries
High
Moorhen
Gallinula chloropus
Rail
Resident (some winter immigrants)
Freshwater
High
Golden plover
Pluvialis apricaria
Wader
Breeding & winter immigrant
Uplands and coast
High
Lapwing
Vanellus vanellus
Wader
Breeding & winter immigrant
Farmland and coast
High
Curlew
Numenius arquata
Wader
Breeding
Inland and coast
High
Black-headed gull
Larus ridibundus
Gull
Breeding & winter immigrant
Freshwater, farmland and coast
High
Common gull
Larus canus
Gull
Breeding & winter immigrant
Freshwater, farmland and coast
High
Lesser black-backed gull
Larus fuscus
Gull
Breeding & winter immigrant
Larger lakes and coast
High
Herring gull
Larus argentatus
Gull
Breeding & winter immigrant
Larger lakes and coast
High
Greater black-backed gull
Larus marinus
Gull
Resident
Larger lakes and coast
High
Little grebe
Tachybaptus ruficollis
Grebe
Resident
Freshwater and coast
Med
Great crested grebe
Podiceps cristatus
Grebe
Breeding & winter immigrant
Freshwater and coast
Med
Cormorant
Phalacrocorax carbo
Cormorant
Breeding & winter emigrant
Coast and freshwater
Med
Light-bellied brent goose
Branta branta hrota
Goose
Winter immigrant
Estuaries, coast, grassland
Med
Avian Flu Risk Assessment Wild Birds 27/10/2006
Figure 1: Wild bird species of greatest risk with regard to carrying HPAI H5N1 to
Ireland or transmitting the virus within the country.
(Pdf file of bird spcies photos to be inserted here)
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Avian Flu Risk Assessment Wild Birds 27/10/2006
Figure 2: Map of Ireland showing wetland habitats with the greatest densities of
waterfowl representing higher risk areas for avian influenza introduction.
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Avian Flu Risk Assessment Wild Birds 27/10/2006
Figure 3. Avian Influenza restricted zone notice.
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