Avian Flu Epidemic Reveals Holes in the Net

Avian Flu Epidemic Reveals Holes in the Net
United Daily News editorial (Taipei, Taiwan, ROC)
A Translation
January 14, 2015

Executive Summary: Can Taiwan wage a "decisive offshore battle?" If the battle is over avian influenza, then Taiwan has already fallen to the enemy. Immunization units have belatedly engaged in culling, disinfection, and isolation. Public health physicians have promoted food safety efforts. But these merely plug holes in the net. Ten years ago, the avian flu first appeared in Taiwan. Vaccinations should have become standard operating procedure. Unfortunately, the net remains riddled with holes.

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Can Taiwan wage a "decisive offshore battle?" If the battle is over avian influenza, then Taiwan has already fallen to the enemy. Immunization units have belatedly engaged in culling, disinfection, and isolation. Public health physicians have promoted food safety efforts. But these merely plug holes in the net. Ten years ago, the avian flu first appeared in Taiwan. Vaccinations should have become standard operating procedure. Unfortunately, the net remains riddled with holes.

From a risk management perspective, the government's response leaves people speechless. An epidemic prevention network must be established before migratory birds arrive from the north, not hastily concocted after an outbreak has already occurred. An old adage states, "Do not hope the enemy will not attack. Prepare for any kind of attack." This is the iron law of epidemic prevention. Yesterday COA chairman Chen Bao-ji said "If the mortality rate exceeds 20%, we will cull." But that merely cleans up the mess. One has already lost the initiative.

Each year migratory birds wintering in the south arrive on Taiwan very punctually. By mid-October, they have arrived on Taiwan. They return north the following April. Once a year, migratory birds are man's honored guests. Naturally we welcome them. But poultry farms are often hotbeds for mutating viruses spread by migratory birds, waterfowl, and waders. Therefore when migratory birds arrive in October,epidemic prevention agencies should be on full alert. Migratory birds will not wait until we are ready before they spread viruses. Waterfowl and waders in particular, often carry diseases. For humans, this requires a cautious response.

Migratory birds are the biggest hosts when it comes to the seasonal spread of viruses. This is something those charged with epidemic control must understand. Academic research on migratory birds is a mature science. Unfortunately Taiwan has yet to apply this science. It has not gone beyond birdwatching. Taiwan has a good reputation for the scientific tracking of migratory bird patterns. But it has yet to apply this knowledge to epidemic prevention.

Taiwan is a hot spot for migratory birds wintering in the south. They arrive on Taiwan from the east, from Sakhalin, Japan, the Korean Peninsula, and Okinawa. They arrive on Taiwan from the west, from Siberia, Heilongjiang, Yancheng, and Poyang Lake Sanctuary. Flight paths and migratory times are fixed. Taiwan is a hot spot because birds fly long distances over land or water. When they encounter headwinds, they need to rest and live off the land. Taiwan for them, has become a Mecca.

Ecologists have urged government land planners to factor in the routes taken by migratory birds. These are high-risk areas for avian influenza. Poultry farms should not be located in these regions. Birds have no bladders. Their feces and urine get mixed together. They indiscriminately discharge these wastes along their flight paths. The avian influenza virus is replicated in the digestive tracts of birds. Therefore the flight paths for migratory birds are high risk zones for avian influenza. But bird excretions are not concentrated in breeding ground waters. Nor are they discharged in the vicinity of feed buckets. Therefore the decision of epidemic prevention units to add bird netting to feed buckets is not necessarily a scientific one.

Ignorance about new viruses is also a major problem. The newly emerged H5N2 virus that has appeared on Taiwan is not the same H5N2 that appeared in the past. Its H gene came from Korea. Its N gene came from the Mainland. The two are very similar. It is impossible to tell the difference. It is impossible to determine whether the new virus is a mutation of the virus from the migratory birds' previous habitat, or a mutation that developed after entering Taiwan. Heavier concentrations of chlorine disinfectants merely suppress the virus. They are not a remedy.

To plug the holes, we must do more than fight a "decisive offshore battle." Regional cooperation is also essential. Before the outbreak on Taiwan, South Korea issued reports of bird flu. This gave Taiwan ample warning. The Korean Peninsula is the birds' previous stop in their southward migration. Taiwan cannot avoid being affected. On Mainland China, for example, the wetlands monitoring system set up by the Mainland's State Forestry Administration is now three years old. It boasts world-class standards. It monitors the migration of wetland waterfowl, and waders, and possible mutations of the virus. This is the role that wetlands play in disease prevention. The Korean Peninsula, Taiwan, Mainland China, the Hong Kong Mai Po Reserve, and other monitoring units should share data promptly. This would help control any future outbreaks.

Taiwan should improve the sensitivity of Taiwan region outbreak detection. This would aid the international exchange of information. For example, migratory birds arrived on Taiwan last October. Suppose they had brought with them new, high risk viruses? Poultry farms would have been affected. Egg production would have declined. Poultry would have suffered increased mortality. Such numbers in isolation may not mean much. But combine them with regional data, and trends become apparent. The more data gathered from neighbouring countries, the clearer the picture. This is something one must realize.

Other factors include human interference with migratory patterns. These are not yet fully understood. They include the impact of wind turbines and wind farms on the path of migratory birds, as well as aircraft take offs and landings that disturb airflow on runways. All these can lead to abnormal animal responses. These are all important indicators of changes in avian influenza. Ignore them and may the price.

The key however remains to “wage a decisive offshore battle." That remains an iron law.

禽流感疫情顯示防疫網破漏累累
2015-01-14 02:28:08 聯合報 社論

從「防疫決戰於境外」的角度審視這波禽流感疫情，毫無疑問，台灣淪陷了。雖然防疫單位事後全力撲殺、消毒、隔離，公衛醫生全力宣導食安，也只能算是「補破網」。事實上，十年前禽流感首度在台灣出現，防疫該怎麼做即應有標準作業程序；遺憾的是，這張網至今仍然破漏累累。

從風險管理的角度看政府應變，實讓人無言。簡言之，防疫網必須在候鳥南來之初即應張起，而非等疫情爆發，才手忙腳亂地張網。所謂「勿恃敵之不來，恃吾有以待之」，就是防疫工作顛撲不破的鐵律。農委會主委陳保基昨天說，「死亡率過兩成就撲殺」；但這只是在收拾殘局，卻已完全失去制敵先機。

每年候鳥南遷來台度冬其實相當「守時」，十月中旬陸續抵台，第二年四月北返。候鳥是人類每年一會的嬌客，我們當然歡迎；然而，北方南遷的候鳥，水禽、涉禽在繁殖區水域有頻密的病毒交換，病毒變種的機率甚高；因此，十月中候鳥光臨時，防疫部門就應繃緊神經。候鳥不會等安營紮寨後才釋放病毒，尤其水禽、涉禽通常能帶毒而不發病；對人類而言，這需謹慎應對。

候鳥是季節病毒傳播最主要的宿主，這是防疫指揮官必須具備的基本認識。遺憾的是，學術上對候鳥的研究已經相當成熟，但在台灣的應用，卻始終未跨出賞鳥之用。台灣在追蹤候鳥、路徑、數量上，享有很高的科學聲望，卻一直未被引介至防疫工作。

台灣是候鳥南遷度冬的熱點。無論是庫頁島、日本、朝鮮半島、沖繩來台的東線，或是西伯利亞、黑龍江、鹽城、鄱陽湖保護區抵台的西線，飛行路徑、移棲時間都很固定。台灣之所以成為熱點，是因為鳥類經陸域或海域的長距離飛行，遇上氣流條件不佳，亟需歇腳覓食之地，台灣就成了款客最佳所在。

生態學界曾建議，政府的國土規劃應該標註候鳥移棲路線，因為此一路徑是禽流感高風險區，應禁止家禽養殖場設置。主要是禽鳥沒有膀胱，大、小便在泄殖腔混合後，沿著飛行路徑隨意排放；加上禽流感病毒是在禽鳥消化道複製，因此候鳥飛行路線是禽流感的高風險地帶。然而，候鳥排泄並不集中在養殖場水域，更不會排放在飼料桶附近；因而，防疫單位認為飼料桶應加覆防鳥網，未必是科學推論。

對新病毒機轉的無知，也是一大問題。新出現的Ｈ５Ｎ２，與過去台灣出現過的Ｈ５Ｎ２並不相同；其Ｈ基因來自韓國，Ｎ基因來自大陸，兩者相似度非常高，但分辨不出差異何在，無法據此推論這個全球首見新病毒是候鳥客人前一個棲地的病毒重組，或者入境台灣後的突變。亦即，加重氯濃度的消毒只是壓制作用，而非對症下藥。

除了「決戰境外」的認知，區域合作也是我們必須補上的缺口。在台灣疫情爆發前，南韓即有禽流感疫情傳出，這當然是台灣的警訊，因為朝鮮半島是候鳥南遷之前站，不可能不影響台灣。以中國大陸為例，中共國家林業局設置的濕地監控系統已進入第三年，具世界級水準。濕地水禽、涉禽頻密地移棲，可以在第一時間監控到病毒可能的變異，這是濕地對防疫最積極的作用。台灣若與朝鮮半島、大陸、香港米埔保護區等監測單位合作，取得第一時間的病毒監控資料，勢必更有助於掌控疫情。

台灣若能提升境內疫情偵測的敏銳度，也能回饋國際的資訊交流。例如，去年十月候鳥抵台，若是攜來新的、危險性大的病毒，則家禽養殖場必然會受影響，最常見的是產蛋率下降、致死率增高等。這些數字，個別看或不覺得具指標意義，但若匯集各地區數字，就能看出趨勢。若再比對鄰近國家數據，面貌即更清晰，這是不能不繃緊神經的。

除此之外，還有更多人為因素干擾生物移棲的變數，尚待解開。例如風力發電機風場對候鳥路徑的影響、飛機起降跑道的干擾氣流等，都會造成生物的異常行為及生理反應，都是禽流感變異觀察的重要指標；一旦忽視，即可能要付出巨大代價。