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Published Date: 2006-06-16 00:00:00
Subject: PRO/AH> Avian influenza (137) - Denmark
Archive Number: 20060616.1675

AVIAN INFLUENZA (137) - DENMARK
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Date: Fri, 16 Jun 2006
From: ProMED-mail<promed@promedmail.org>
Source: Eurosurveillance Weekly release, Vol.11 Iss.6, 15 Jun 2006 [edited]
<http://www.eurosurveillance.org/ew/2006/060615.asp#2>

The identification and management of H5N1 avian influenza in Denmark in
2006 has been facilitated by close collaboration between the animal and
human health authorities and institutions, at national and local level.
Public expressions of concern have been well-informed and calm, and media
reporting has been responsible.
Avian influenza A/H5N1 is currently not a very contagious virus for humans,
but there is a small and real risk of infection for people who have close
contact with sick birds. Even in an industrialised country with a
well-informed population, delays in case ascertainment affect the
management of an outbreak. At present, it is impossible to know whether
avian influenza H5N1 has become endemic in Danish wild birds, or, if it has
not, whether it is likely to be reintroduced later. It is therefore
important to maintain timely surveillance, preparedness and communication
lines between the relevant stakeholders.
Wild birds
----------
The first detection of highly pathogenic avian influenza A H5N1 in Denmark
was on 14 Mar 2006 in a common buzzard (_Buteo buteo_) found on Svino near
the town of Naestved in the southern part of Sjaelland. Subsequently highly
pathogenic avian influenza A H5N1 was found in 43 wild birds through
passive surveillance in various locations in Denmark, mainly areas
bordering the Baltic Sea along the Eastern migratory flyways. Avian
influenza has also been detected in a pooled sample of herring gull (_Larus
argentatus_) faeces. Among the various types of bird tested, the rates of
positive findings have been highest in waterfowl, particularly swans and
ducks. The most recent positive findings in wild birds were made on 2 May
2006. More detailed information is available in Danish and English from the
Danish Veterinary and Food Administration [1].
Backyard poultry holding
------------------------
An outbreak of highly pathogenic avian influenza A H5N1 in a poultry flock
was confirmed on 18 May 2006. It occurred in a backyard holding in Funen
county, in an area where avian influenza A H5N1 had previously been
detected in wild birds. The flock consisted of 102 birds (51 chickens, 41
ducks, 5 geese, 3 guinea fowls, and 2 peacocks) of which 47 died between 3
and 12 May 2006. The birds were kept in 4 different sections located on
different parts of the farm, and the sick birds all belonged to the same
section which held about 50 birds. The birds in the affected section were
all free-ranging and thus exposed to wild birds. When the owner became
aware of the outbreak, he implemented biosecurity measures. Changes of
clothing and footwear seemed to be sufficient to prevent the spread of the
disease to the other sections. All the birds from the 3 non-affected
sections were culled, but were tested H5N1-negative.
The 2 people living on the farm both had close contact with the birds. They
culled sick birds on their own initiative without using any personal
protective devices such as masks or gloves. They reported that they got
bird blood on their bare hands during this process. In addition, there had
been visitors at the farm on more than one occasion, including a person who
came on 8 May, and 3 visitors who purchased eggs for home cooking use on 10
May. There was a considerable delay between the onset of the outbreak on 3
May 2006 and the notification to the district veterinary officer on the
evening of 17 May 2006.
By 18 May, a total of 6 people had been directly exposed to sick poultry
since 3 May. These included the 2 people living on the farm, one of the 3
visitors who came to purchase eggs on 10 May, and a veterinarian and 2
cullers (personal protective devices were used by the veterinarian and the
cullers). Following guidance from the WHO and the European Centre for
Disease Prevention and Control, these 6 persons were all recommended to
take oseltamivir for post-exposure prophylaxis (which they duly accepted),
and were asked to report any illness with fever to the local public health
authority [2,3]. The owners were also instructed to keep out of the areas
where the birds had been until these areas had been cleaned and disinfected
by a contracted cleaning company. No one developed signs or symptoms
compatible with human infection with avian influenza virus.
A family of 5 had received a delivery of fresh table eggs from the farm on
16 May, and ate these eggs fried (that is, with runny, partially cooked
yolks) the following day. As a precautionary measure, these individuals
were recommended oseltamivir prophylaxis on 20 May. One of the family
members developed a sore throat on 18 May, but the family doctor, in
consultation with specialists in infectious disease, did not judge the
signs to be compatible with avian influenza in humans and it was decided
that testing was not justified. No other symptoms have been reported from
this family.
The visitor who came on 8 May has since been well, with no symptoms of
influenza-like illness, and was not prescribed antiviral drugs, since more
than 10 days had already passed since exposure. 2 of the 3 visitors who
came on 10 May stayed at the farmhouse and were not directly exposed to the
birds, and were consequently not offered antiviral drugs. Another delivery
of fresh table eggs was made from the farm to a household on 15 May; and
although it is theoretically possible that these individuals may have been
exposed to avian influenza virus, they were not offered antiviral drugs
because they reported that they did not cook, eat or otherwise handle the
eggs but kept them in their packaging in the refrigerator.
Game bird holding
-----------------
On 2 Jun 2006, low pathogenic avian influenza H5N2 was detected in a game
bird holding, also in Funen county. There were no reported clinical signs
of disease among the animals. Mallard (_Anas platyrhynchos_) ducklings from
the holding were tested as part of the Danish surveillance programme for
avian influenza in poultry. At the initial testing, the virus was found to
be A/H5, but the neuraminidase type was unknown. Although a highly
pathogenic avian influenza (such as A H5N1) was considered to be unlikely,
given the absence of bird deaths, it was considered reasonable to offer the
owners and the personnel working at the holding antiviral drugs for post
exposure prophylaxis. Nearly 90 people had recently purchased live
ducklings from the holding and 50 people had been involved in the culling
of the 19 500 birds, and all were eligible for post exposure prophylaxis.
However, before prophylaxis could be offered to the duckling purchasers and
cullers, it became clear that the viral strain was a low pathogenic H5 type
that had not been described as a cause of illness in humans. Therefore, the
prophylaxis was not distributed to this group, and treatment of the owners
and the personnel working at the holding who had already started a course
of prophylaxis was discontinued.
References:
1. Danish Veterinary and Food Administration. Avian influenza (bird flu) page.
(<http://www.uk.foedevarestyrelsen.dk/AnimalHealth/Avian_influenza/forside.htm>)
[accessed 14 Jun 2006]
2. World Health Organization WHO: Rapid Advice Guidelines on
pharmacological management of humans infected with avian influenza A (H5N1)
virus, May 2006
(<http://www.who.int/csr/disease/avian_influenza/guidelines/pharmamanagement/en/index.html>).
3. ECDC guidelines to minimise the risk of humans acquiring highly
pathogenic avian influenza from exposure to infected birds or animals.
Stockholm: European Centre for Disease Prevention and Control; version 21
Dec 2005.
(<http://www.ecdc.eu.int/avian_influenza/H5N1_Occupational_Guidance_ECDC_051019.pdf>).
[accessed 15 Jun 2006]
--
ProMED-mail
<promed@promedmail.org>
[This first-hand paper provides a useful, clear and transparent description
of the Danish situation, from animal as well as public health aspects. It
would help to know whether the 2 affected establishments had fulfilled the
prescribed biosecurity measures prior to the incidents. This is
particularly applicable to the apparently commercial game bird holding. -
Mod.AS]

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