國際鳥盟：病毒由野鳥傳播的可能性不高
歐盟執委會13日根據「歐盟參考實驗室」在義大利、希臘及保加利亞採樣檢測結果，證實上述國家境內的野生天鵝身上帶有致命的H5N1禽流感病毒。在斯洛維尼亞方面，斯洛維尼亞實驗室在一隻野生天鵝身上檢測出禽流感陽性反應，其檢體已被送往歐盟位於英國威布瑞的參考實驗室作進一步檢測。
斯洛維尼亞當局承諾歐盟執委會將立即實施預警措施，規格將完全比照執委會規定──執委會已於10日，以及11、12日期間，分別對希臘與義大利下達同等級的預警措施指示。
執委會規定的預警措施包含，在禽流感爆發地點方圓3公里內設立高風險警戒區，並將方圓10公里區域劃入高度監控範圍。
在警戒區域中，必須將家禽留在室內，同時除了直接送往屠宰場外，禁止移動家禽。除非肉品來自註冊過的飼養場的健康動物，並且經由屠宰場的獸醫在宰殺前後檢疫合格，否則任何肉品都不能運出該區。
在警戒區與監控區，必須加強飼養場的現場生物安全措施，禁止捕獵野鳥，同時必須對家禽養殖者及其家人進行相關的衛生宣導教育。
鳥類保育組織「國際鳥盟」表示，假使野鳥在疾病傳遞中扮演了任何角色，影響也比未處理家禽、家禽產品的移動、及家禽全球貿易等其他傳染機制來得小。同時國際鳥盟也表示，另一種受到懷疑的傳染機制則是使用受感染的家禽糞肥作為農業和水產養殖的肥料，或作為魚類、豬隻養殖場的飼料。
雖然少數爆發的病例與候鳥遷徙的方向與時機相符，但大多數都不相關，因此國際鳥盟表示，此情形意味著2005年秋季往返的候鳥中，並沒有散播H5N1病毒的水鳥。截至目前為止，在印度、菲律賓群島、太平洋、和非洲等區域的候鳥度冬場所，均尚未有的發現H5N1病毒的報告。
證據顯示，H5N1病毒對遷徙性野鳥具高度致命性，受到感染的候鳥無法長距離飛行；因此，國際鳥盟認為病毒非常可能僅受限於致死病例的週遭地區。
因此，國際鳥盟認為：「野鳥可能與某些H5N1病例的爆發有關（更有可能都無關），但是其他原因似乎更為迫切且重要──同時這類原因也應該是控制禽流感各項努力的當務之急。」
Bird flu of the deadly H5N1 strain has been confirmed in wild swans in Italy, in Greece, and in Bulgaria, the reference laboratory that tested samples from those countries told the European Commission today. In Slovenia, a wild swan tested positive for the disease at the Slovenian Laboratory for Avian influenza, and samples have been sent to the EU Reference Laboratory for Avian Influenza in Weybridge, UK for further tests.
The Slovenian authorities have given a commitment to the European Commission to apply immediately the same precautionary measures as those set out in the Commission Decision adopted for Greece on Friday, and applied in Italy during the weekend.
Precautionary measures involve establishing a three kilometer (two mile) high risk area around each of the outbreaks and a surrounding surveillance zone of 10 kilometers.
In the protection zone, poultry must be kept indoors and movement of poultry is banned except directly to the slaughterhouse. No meat may be sent outside the zone unless the meat is sourced from healthy animals in registered farms, and is subject to checks by slaughterhouse veterinarians both before and after slaughter.
In both the protection and the surveillance zones, on-farm biosecurity measures must be strengthened, hunting of wild birds is banned, and disease awareness education of poultry owners and their families must be carried out.
The bird conservation organization BirdLife International says if wild birds have any role, it is minor compared to other mechanisms such as movements of untreated poultry and poultry products, and the global trade in poultry. Another suspected mechanism is the use of infected poultry manure as fertilizer in agriculture and aquaculture, and as feed in fish-farms and pig farms, BirdLife says.
While a few outbreaks are consistent with the direction and timing of wild bird migration, most are not, BirdLife says, pointing out that 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 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, BirdLife maintains.
So, BirdLife concludes that "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 control efforts."
