prelease for Mute swans from Western Europe to GB and from Eastern Europe to Italy is (Table 6). H5N1 was confirmed in 16 Mute swans wintering in the medium south of Italy in 2006 (Terregino et al. 2006). Those birds are believed to have migrated from the Black Sea region of eastern Europe. The prediction of a low prelease for Whooper swans arriving in GB albeit from Western Europe (Table 6) is interesting in the light of the H5N1-infected bird found dead on the east coast of Scotland on 29 March 2006 (Blissitt 2007). It is possible that the swan was actually infected within GB and that it was effectively a sentinel dead swans being large and – white are conspicuous (Newmann 2009). Indeed, most Whooper swans in GB et al. come from Iceland in October rather than March (Brazil 2008). It could, however, have been infected in continental Europe and then flown to Scotland. Indeed, the probabilities of H5N1-infected Whooper surviving migration from Western swans’ Europe and still shedding virus on arrival in GB are It should also be noted there high. was an outbreak of H5N1 in the Baltic Sea in February 2006 with increased mortality among Mute swans and Whooper swans (see Teifke 2007) such that the local et al. pprev at that time would have been high. Mixing of different wildfowl species is well documented (see Fig 15 of Rees 2006). Horizontal transmission from one bird to another in the migration chain is difficult to incorporate in this release assessment. However transmission through a “baton effect” between different individual birds at stopover sites would be accommodated by the values of pprev used for Western Europe, Eastern Europe and NAEA in this release assessment. Although there are quantitative data available for many of the parameters, a qualitative approach was adopted here because of the uncertainty both in the geographic ranges of the birds and the timings reflecting the lengths of the stopovers
prelease for Mute swans from Western Europe to GB and from Eastern Europe to Italy is medium (Table 6). H5N1 was confirmed in 16 Mute swans wintering in the south of Italy in 2006 (Terregino et al. 2006). Those birds are believed to have migrated from the Black Sea region of eastern Europe. The prediction of a low prelease for Whooper swans arriving in GB albeit from Western Europe (Table 6) is interesting in the light of the H5N1-infected bird found dead on the east coast of Scotland on 29 March 2006 (Blissitt 2007). It is possible that the swan was actually infected within GB and that it was effectively a sentinel – dead swans being large and white are conspicuous (Newmann et al. 2009). Indeed, most Whooper swans in GB come from Iceland in October rather than March (Brazil 2008). It could, however, have been infected in continental Europe and then flown to Scotland. Indeed, the probabilities of H5N1-infected Whooper swans’ surviving migration from Western Europe and still shedding virus on arrival in GB are high. It should also be noted there was an outbreak of H5N1 in the Baltic Sea in February 2006 with increased mortality among Mute swans and Whooper swans (see Teifke et al. 2007) such that the local pprev at that time would have been high. Mixing of different wildfowl species is well documented (see Fig 15 of Rees 2006). Horizontal transmission from one bird to another in the migration chain is difficult to incorporate in this release assessment. However transmission through a “baton effect” between different individual birds at stopover sites would be accommodated by the values of pprev used for Western Europe, Eastern Europe and NAEA in this release assessment. Although there are quantitative data available for many of the parameters, a qualitative approach was adopted here because of the uncertainty both in the geographic ranges of the birds and the timings reflecting the lengths of the stopovers
H5N1_HPAI_bird_release_Ref_comments_addressed.docx