Author(s):
Fabião, António 
; Rodrigues, David ; Figueiredo, Maria Ester ; Encarnação, Vitor
Date: 2006
Persistent ID: http://hdl.handle.net/10400.5/1380
Origin: Repositório da UTL
Subject(s): duck; avian influenza; Portugal
Description
The outbreak of highly pathogenic avian
influenza of the H5N1 virus subtype in Western
European countries induced the fear that it could
reach Portugal through wild bird migration. Ducks,
geese and swans are some of the bird groups with
higher prevalence of influenza virus that might be
vectors of virus dissemination, considering the
existing studies on low pathogenic subtypes that are
common in nature (Olsen et al. 2006), and also
occur in Portugal (D. Rodrigues et al., unpublished
data). Although swans do not occur frequently in
Portugal and geese are mostly restricted to Tagus
River Estuary Nature Reserve (e.g. Farinha & Costa
1999), ducks are common in Portugal and mostly
concentrated on wetlands near the coast (Costa &
Guedes 1997), and wintering Aythya duck species
are much less numerous than wintering Anas
species (e.g. Costa & Guedes 1997). The Portuguese
total wintering duck population (Costa & Guedes
1997) is relatively small when compared to the total
European population (Scott & Rose 1996),
probably due to the location of the country on the
South-West limit of the distribution for most of the
species (Scott & Rose 1996). However, given the
recent occurrence of outbreaks of highly
pathogenic avian influenza of the H5N1 subtype in
France, Germany, Scotland, Denmark, Sweden and
Poland (OIE 2006), there is a risk that outbreaks
may also occur in Portugal.
In this paper, we aim to discuss the possibility
of avian influenza occurrence in Portugal, under
the assumptions that outbreaks will persist, will
occur new ones or the virus will become endemic
on the above mentioned countries and that ducks will be vectors of the virus
