Are migrating wild birds spreading High Pathogenicity Avian Influenza H5N1?
Possibly – but this is unproven and (evidence suggests) unlikely. If wild birds have any role, it is minor compared to other mechanisms. While a few outbreaks are consistent with the direction and timing of wild bird migration, most are not. The 2005 autumn migration came and went without migrating waterbirds spreading H5N1. The virus has not so far been reported from the birds’ wintering areas in India, the Philippines, the Pacific and Africa. The detailed pattern of outbreaks is also inconsistent with what would be expected from the movements of wild birds. All the evidence suggests that H5N1 is highly lethal to migratory wild bird species, and kills them quickly; that infected migrants cannot move long distances; and that the virus is most likely to be contracted locally, close to the site of deaths. In short, wild birds could possibly have been involved in some H5N1 outbreaks (more likely in none) but other factors appear to be much more important – and should be the first focus of
Possibly but this is unproven and (evidence suggests) unlikely. If wild birds have any role, it is minor compared to other mechanisms. While a few outbreaks are consistent with the direction and timing of wild bird migration, most are not. The 2005 autumn migration came and went without migrating waterbirds spreading H5N1. The virus has not so far been reported from the birds’ wintering areas in India, the Philippines, the Pacific and Africa. The detailed pattern of outbreaks is also inconsistent with what would be expected from the movements of wild birds. All the evidence suggests that H5N1 is highly lethal to migratory wild bird species, and kills them quickly; that infected migrants cannot move long distances; and that the virus is most likely to be contracted locally, close to the site of deaths. In short, wild birds could possibly have been involved in some H5N1 outbreaks (more likely in none) but other factors appear to be much more important and should be the first focus of con
3.3 Can ‘healthy’ wild birds carry the HPAI H5N1 virus? 3.4 Is H5N1 a conservation threat? 3.5 What further research is needed? 3.6 Should wild birds be culled to stop the disease spreading? 3.7 Should wetlands be drained to deter waterbirds? 4. Can I still go birdwatching? Should I stop feeding wild birds in my garden? 5. How is the virus spread, if not by wild birds? 6. What should be done to prevent the spread of HPAI H5N1? 1. WHAT IS HIGH PATHOGENICITY AVIAN INFLUENZA H5N1? There are numerous different strains of avian influenza, but only a very few of these are a serious health concern for animals or people. Most strains circulate in wild birds, especially waterbirds, at low levels, and at worst cause only mild disease. These ‘Low Pathogenicity Avian Influenza’ (LPAI) viruses also have only mild effects on poultry. In contrast, some variants of the H5 and H7 ‘subtypes’ can cause massive mortality in poultry. These are designated ‘High Pathogenicity Avian Influenza’ (HPAI). HPAI vi
