導讀：
1月19日與在美國波士頓的女兒聊天，她說起已經有近兩周買不到雞蛋，蛋液產品也銷售一空，原因是美國禽流感疾病帶來的影響，當然在2月初超市恢復了雞蛋供應；1月13日與在禾豐進行家禽技術交流的荷蘭皇家德赫斯公司蛋禽專家Arien溝通，他談到當時在荷蘭每只蛋雞的利潤達到了稅前27歐元，如此高利潤的原因之一，也是因為歐洲禽流感帶來的雞只數減少的影響。可見，禽流感在歐美市場對雞蛋消費者和養殖從業者都產生了明顯的影響。所以本期就禽流感的話題請JAN根據合作伙伴荷蘭皇家德赫斯公司的技術觀點和他個人閱讀的大量文章，組織了這篇短文，請大家尤其是關心禽流感對公共衛生安全影響的人士了解，不必要產生恐慌。
在禽(qin)(qin)流(liu)感(gan)作(zuo)為(wei)人畜共患病(bing)(bing)的(de)(de)(de)風(feng)險(xian)方面，本文的(de)(de)(de)觀點(dian)是(shi)：目前沒(mei)(mei)有證據表(biao)明禽(qin)(qin)流(liu)感(gan)可以通過食用任(ren)何市售食品(pin)（包括受(shou)污染(ran)的(de)(de)(de)禽(qin)(qin)類產(chan)品(pin)）傳播給人類。人類感(gan)染(ran)禽(qin)(qin)流(liu)感(gan)的(de)(de)(de)情(qing)況仍然罕(han)見，且迄今為(wei)止(zhi)尚(shang)未發現人際傳播。研究表(biao)明，禽(qin)(qin)流(liu)感(gan)病(bing)(bing)毒(du)與禽(qin)(qin)類受(shou)體(ti)（α2,3唾(tuo)液酸(suan)）結合，而非人類季節性(xing)流(liu)感(gan)病(bing)(bing)毒(du)使用的(de)(de)(de)受(shou)體(ti)（α2,6唾(tuo)液酸(suan)），這(zhe)是(shi)該(gai)病(bing)(bing)毒(du)具(ju)有物種特異性(xing)且對(dui)人類沒(mei)(mei)有危險(xian)的(de)(de)(de)原因之一。世界衛生組(zu)織（WHO）、歐洲(zhou)食品(pin)安(an)全局（EFSA）和聯合國糧農組(zu)織（FAO）的(de)(de)(de)多家(jia)權威機(ji)構將禽(qin)(qin)流(liu)感(gan)對(dui)普(pu)通公眾的(de)(de)(de)風(feng)險(xian)標記(ji)為(wei)“低”，而對(dui)經常接觸感(gan)染(ran)動物的(de)(de)(de)人群(qun)風(feng)險(xian)標記(ji)為(wei)“低至中度”。相關(guan)權威機(ji)構會定(ding)期評估病(bing)(bing)例數量和風(feng)險(xian)水平。
——首席技術官(guan) 邵彩梅
文/荷蘭皇家德(de)赫斯公司(si)駐禾(he)豐技術總監
Jan Cortenbach
翻譯/總部高級研發經理(li) 張鑫
Avian influenza (AI) is a highly contagious disease primarily found in birds. The first cases of low pathogenic AI (LPAI) were already reported in 1960, and the highly pathogenic AI (HPAI) was first reported in 1996 in geese in China. Sometimes the virus also infects mammals. Avian influenza affects the respiratory (nose, mouth, and airways), digestive, and/or nervous systems. The disease occurs in poultry raised on farms (like chickens, ducks, and turkeys) and nearly all species of birds found in the wild, including ducks, doves, pigeons, geese, seagulls, and storks. Birds of prey and other predators can also contract the virus by eating birds that fell ill or died of avian flu.
禽(qin)流感（Avian Influenza, AI）是一(yi)種主要在(zai)鳥類(lei)中(zhong)(zhong)傳播的高度傳染性疾病(bing)(bing)。低致病(bing)(bing)性禽(qin)流感（Low Pathogenic Avian Influenza, LPAI）的首(shou)(shou)例(li)(li)病(bing)(bing)例(li)(li)早在(zai)1960年(nian)就有報道，而高致病(bing)(bing)性禽(qin)流感（Highly Pathogenic Avian Influenza, HPAI）則(ze)于1996年(nian)首(shou)(shou)次(ci)在(zai)中(zhong)(zhong)國鵝群中(zhong)(zhong)被報出。該(gai)病(bing)(bing)毒(du)有時也會感染哺乳(ru)動物。禽(qin)流感主要影響呼(hu)吸(xi)系(xi)統（鼻、口腔和(he)呼(hu)吸(xi)道）、消(xiao)化(hua)系(xi)統或(huo)神經系(xi)統。該(gai)疾病(bing)(bing)多發于農(nong)場飼養的家禽(qin)（如(ru)雞、鴨(ya)和(he)火雞），以及幾乎所有野生鳥類(lei)，包括鴨(ya)、鴿子、鵝、海(hai)鷗(ou)和(he)鸛(guan)等。猛(meng)禽(qin)和(he)其它捕食性動物也可能通過食用患(huan)病(bing)(bing)或(huo)死于禽(qin)流感的鳥類(lei)而感染該(gai)病(bing)(bing)毒(du)。
Avian influenza can spread via direct contact between animals (live bird) markets, droppings of infected (wild) birds, or dust in the air of infected farms. AI mainly occurs in autumn and winter, when wild birds are mitigating. As expected, more and more AI infections have been identified over the last few weeks in different European regions. The virus was found in both wild birds and commercially kept poultry. The pressure of infection is expected to systematically increase over the next weeks. Due to lower temperatures, higher humidity, and foggy weather, viruses have a longer survival time and are more easily introduced into poultry houses.
禽流感(gan)(gan)可以(yi)通過以(yi)下途徑傳播：動物之間(jian)(jian)的(de)(de)(de)(de)直接接觸（如(ru)活禽市(shi)場），患病（野(ye)生）鳥(niao)類(lei)的(de)(de)(de)(de)糞便，或疫區(qu)農場空氣(qi)中的(de)(de)(de)(de)粉塵。禽流感(gan)(gan)主要發(fa)(fa)生在(zai)(zai)(zai)秋(qiu)季和冬季，此時野(ye)生鳥(niao)類(lei)正(zheng)(zheng)在(zai)(zai)(zai)遷徙。正(zheng)(zheng)如(ru)預期的(de)(de)(de)(de)那樣，過去幾周在(zai)(zai)(zai)歐洲不同(tong)地區(qu)發(fa)(fa)現了越(yue)來(lai)越(yue)多(duo)的(de)(de)(de)(de)禽流感(gan)(gan)感(gan)(gan)染病例。該病毒在(zai)(zai)(zai)野(ye)生鳥(niao)類(lei)和商業化飼養的(de)(de)(de)(de)家禽中均有發(fa)(fa)現。預計在(zai)(zai)(zai)未來(lai)幾周內，感(gan)(gan)染風險(xian)將(jiang)系(xi)統性增(zeng)加(jia)。由(you)于氣(qi)溫降低、濕度增(zeng)加(jia)以(yi)及多(duo)霧天氣(qi)，病毒的(de)(de)(de)(de)存(cun)活時間(jian)(jian)延(yan)長(chang)，并且更容易傳入(ru)禽舍(she)。
As mentioned before, there are two main types of avian influenza, HPAI and LPAI. HPAI is deadly to birds, while LPAI causes several severe symptoms, like tremors, swollen sinuses, decreased weight, and egg production (amongst others). The main concern for LPAI is that it evolves to the HPAI. Since commercial poultry farms usually keep the birds close together, AI outbreaks at such locations affect many birds at once. Wild birds can also contract the highly pathogenic AI variants, which cause a higher risk of HPAI infections at farms located close to rivers and wetland areas.
如前所述，禽流(liu)感主要有兩種類(lei)型：HPAI和(he)LPAI。HPAI對鳥(niao)類(lei)具有致(zhi)命性，而(er)LPAI則會引起一系列嚴重(zhong)癥狀(zhuang)，如震顫、鼻竇腫(zhong)脹(zhang)、體重(zhong)下降(jiang)和(he)產蛋量減少等。LPAI的(de)主要風險在于其可能演(yan)變為HPAI。由于商業化養禽場通常是(shi)密集飼(si)養，一旦發生疫情將立刻產生大(da)量病(bing)例(li)。野生鳥(niao)類(lei)也可能感染高(gao)致(zhi)病(bing)性禽流(liu)感病(bing)毒，這增加了靠近河流(liu)和(he)濕地(di)(di)地(di)(di)區的(de)農場爆發HPAI感染的(de)風險。
Avian influenza: Risk for zoonosis?
Avian influenza can be transmitted from birds to mammals (including humans) mainly in two ways:
Directly from birds or contaminated environments
A. The highest risk applies to mammals that eat infected birds, for example, foxes, raccoons, and cats.
B. Through an intermediate host, such as another mammal
禽流(liu)感：人(ren)畜共患病(bing)的風(feng)險(xian)
禽流感可以從禽類傳播給哺乳動物（包括(kuo)人類），主要通過以下兩種途徑：
直接來自禽類或受(shou)污染的(de)環境
A.最高風險群體是那些(xie)食(shi)用感染禽(qin)類(lei)的哺乳動物(wu)，例如(ru)狐貍、浣熊和貓(mao)。
B.通(tong)過中間宿主，例如另(ling)一只(zhi)哺乳(ru)動物。
In North America, AI has been reported in several dairy herds. Infection in cattle appears to be centered in the udder. The raw milk from infected cows contained high viral loads, indicating a potential route of transmission via milk and milking procedures (rather than respiratory as in birds). Pasteurization inactivates the virus. Apart from cattle, there are cases reported in other mammalian species, like foxes, alpacas, and minks. There is no evidence that AI can be transmitted to humans through the consumption of any commercially available food products including contaminated poultry products. Safe handling of raw meat and other raw food ingredients, thorough cooking, and good kitchen hygiene can prevent or reduce the risks of contaminated food.
在北(bei)美，多個奶(nai)牛群被(bei)報道出(chu)感(gan)染(ran)(ran)了禽(qin)流(liu)(liu)感(gan)。牛感(gan)染(ran)(ran)病毒(du)的(de)部位主要集(ji)中(zhong)在乳房。感(gan)染(ran)(ran)奶(nai)牛的(de)生(sheng)乳中(zhong)含有高病毒(du)載量，表明禽(qin)流(liu)(liu)感(gan)病毒(du)可能通(tong)過(guo)奶(nai)水或(huo)擠奶(nai)流(liu)(liu)程而傳播（與鳥(niao)類(lei)主要通(tong)過(guo)呼(hu)吸道傳播不同(tong)）。巴(ba)氏殺菌(jun)可以滅活病毒(du)。除了牛之外，其(qi)它(ta)哺乳動物（如狐貍、羊駝和(he)水貂）也有感(gan)染(ran)(ran)病例報告。目前沒有證據(ju)表明禽(qin)流(liu)(liu)感(gan)可以通(tong)過(guo)食用任何市售食品(pin)（包括受污染(ran)(ran)的(de)禽(qin)類(lei)產品(pin)）傳播給人(ren)類(lei)。正確處理生(sheng)肉和(he)其(qi)他生(sheng)食原料、徹底烹飪以及良好的(de)廚房衛生(sheng)習(xi)慣可以預防或(huo)降低食品(pin)受污染(ran)(ran)的(de)風(feng)險(xian)。
In Q4 of 2024, 56 new cases of AI infection in humans were reported worldwide. Most of these cases had reported exposure to poultry, live poultry markets, or dairy cattle before virus detection or onset of illness. In case a human does get infected with AI, symptoms are generally mild. These symptoms can include a fever, headache, muscle ache, coughing, and eye inflammation. Sometimes AI in humans results in severe illness with pneumonia, shortness of breath, and even fatalities. These cases mainly occur in Asia.
2024年第四季度(du)，全球(qiu)報告了56例(li)新的人類感(gan)(gan)染(ran)禽(qin)流(liu)感(gan)(gan)病(bing)例(li)。大多數病(bing)例(li)在病(bing)毒檢(jian)測(ce)或發(fa)病(bing)前曾(ceng)接觸(chu)過家(jia)禽(qin)、活禽(qin)市場或奶(nai)牛。人類感(gan)(gan)染(ran)禽(qin)流(liu)感(gan)(gan)后，癥狀通常較輕，可能包(bao)括(kuo)發(fa)熱、頭痛、肌肉(rou)酸痛、咳嗽和(he)眼部炎癥。在某些情況(kuang)下，人類感(gan)(gan)染(ran)禽(qin)流(liu)感(gan)(gan)可能導致(zhi)嚴重疾病(bing)，如(ru)肺炎、呼(hu)吸急促，甚至死亡。這(zhe)些嚴重病(bing)例(li)主要發(fa)生在亞(ya)洲(zhou)地區。
Human infections with AI remain rare and so far, no human-to-human transmission has been identified. With the extensive circulation of AI viruses in bird populations globally, sporadic transmission to humans is likely to continue occurring in settings where people are exposed to infected animals or their environment without appropriate protective equipment. Viruses are also sequenced and genetic changes that may alter zoonotic potential or susceptibility are monitored. Research has shown that the avian influenza virus binds to the avian receptor (α2,3 sialic acids) and not the receptor used by human seasonal influenza (α2,6 sialic acids). This is one of the explanations why the virus is species-specific and not dangerous to humans. Several authorities, like WHO, EFSA, and FAO have marked the risk as ‘low’ for the general public and ‘low-to-moderate’ for those who are regularly exposed to infected animals. The number of cases and risks are assessed on a regular basis by the authorities.
人(ren)類(lei)感染(ran)(ran)禽(qin)流(liu)感的(de)(de)情況(kuang)仍然罕見，且(qie)迄(qi)今為(wei)止(zhi)尚未發現人(ren)際傳播(bo)。隨著禽(qin)流(liu)感病(bing)(bing)(bing)毒在全球鳥類(lei)種群中的(de)(de)廣泛(fan)傳播(bo)，在人(ren)們未使(shi)用適當防護設備的(de)(de)情況(kuang)下(xia)接觸(chu)感染(ran)(ran)動物或其(qi)環(huan)境時，可能會繼續發生零星的(de)(de)傳播(bo)事件。對病(bing)(bing)(bing)毒基因(yin)進行了測序(xu)，并監測可能改變人(ren)畜共患病(bing)(bing)(bing)潛力或易感性的(de)(de)基因(yin)變化。研(yan)究表(biao)明(ming)，禽(qin)流(liu)感病(bing)(bing)(bing)毒與(yu)禽(qin)類(lei)受體(ti)（α2,3唾(tuo)液(ye)酸）結合，而(er)非人(ren)類(lei)季節性流(liu)感病(bing)(bing)(bing)毒使(shi)用的(de)(de)受體(ti)（α2,6唾(tuo)液(ye)酸）。這是該病(bing)(bing)(bing)毒具(ju)有物種特異(yi)性且(qie)對人(ren)類(lei)沒有危險的(de)(de)原因(yin)之(zhi)一。
包括世界衛(wei)生組(zu)織（WHO）、歐洲食(shi)品安全局（EFSA）和(he)(he)聯合國糧農組(zu)織（FAO）在內的多家權(quan)威機構已將禽(qin)流感對(dui)普通公眾的風險(xian)標記為“低(di)(di)”，而對(dui)經常接(jie)觸感染動物(wu)的人群(qun)的風險(xian)標記為“低(di)(di)至中(zhong)度”。相關機構會定期(qi)評估病例數量和(he)(he)風險(xian)水平。
What can be done to prevent avian influenza on poultry farms?
Biosecurity remains a key factor in preventing HPAI virus introduction from wild birds into poultry farms and further between-farm spread. Several important aspects are like employees and visitors, hygiene, feed and feed delivery, cleaning, and disinfection should be taken into account. For biosecurity, it is very important to avoid contact with other birds outside of the farm. Sharing farm equipment and personnel should be avoided or at least kept to a minimum. Furthermore, when new cases are reported, the local authority can govern an obligation to keep all poultry/bird types housed inside (both commercial and backyard). In some countries, the authority follows a ‘stamp-out strategy’ when AI is present on a poultry farm. All animals located at that farm and within a 1 km zone of neighboring farms are culled according to a strict protocol. Furthermore, a 3 km protection zone and 10 km surveillance zone are applied for several weeks. This should prevent further outbreaks from that farm. Vaccination is one of the additional measures to protect birds against AI.
如何預防禽流感在家(jia)禽養殖場的傳播？
生(sheng)物(wu)安(an)全仍然是防(fang)止HPAI病(bing)毒從(cong)野生(sheng)鳥類傳(chuan)入家(jia)禽(qin)養(yang)(yang)(yang)殖(zhi)(zhi)場(chang)(chang)以及(ji)在(zai)(zai)養(yang)(yang)(yang)殖(zhi)(zhi)場(chang)(chang)之(zhi)間進(jin)一(yi)步傳(chuan)播(bo)的(de)關(guan)鍵因素。以下幾個(ge)重要(yao)方面需要(yao)考慮：員工和訪客管理、衛生(sheng)情(qing)況(kuang)、飼料及(ji)飼料運輸、清潔(jie)和消(xiao)毒等。在(zai)(zai)生(sheng)物(wu)安(an)全方面，避(bi)(bi)免與養(yang)(yang)(yang)殖(zhi)(zhi)場(chang)(chang)外(wai)的(de)其他(ta)鳥類接觸(chu)至關(guan)重要(yao)。應避(bi)(bi)免共享養(yang)(yang)(yang)殖(zhi)(zhi)設備及(ji)人員，或(huo)至少將(jiang)其控(kong)制在(zai)(zai)最(zui)低限度。此外(wai)，當(dang)有(you)新病(bing)例(li)報(bao)告時(shi)(shi)，地方當(dang)局可以規定將(jiang)所(suo)有(you)家(jia)禽(qin)/鳥類（包括商業養(yang)(yang)(yang)殖(zhi)(zhi)和家(jia)庭散養(yang)(yang)(yang)）圈養(yang)(yang)(yang)在(zai)(zai)室內。在(zai)(zai)某些國家(jia)，當(dang)禽(qin)流感(gan)出現在(zai)(zai)家(jia)禽(qin)養(yang)(yang)(yang)殖(zhi)(zhi)場(chang)(chang)時(shi)(shi)，當(dang)局會(hui)采取“撲殺策略(lve)”（stamp-out strategy）。根據嚴格協議，對感(gan)染農(nong)場(chang)(chang)及(ji)其周(zhou)邊1公里(li)范(fan)圍內的(de)鄰近農(nong)場(chang)(chang)的(de)所(suo)有(you)動(dong)物(wu)進(jin)行撲殺。同時(shi)(shi)，還會(hui)實施(shi)(shi)(shi)為期(qi)數(shu)周(zhou)的(de)3公里(li)保(bao)護區和10公里(li)監控(kong)區措施(shi)(shi)(shi)，以防(fang)止疫情(qing)進(jin)一(yi)步擴散。疫苗接種是保(bao)護家(jia)禽(qin)免受(shou)禽(qin)流感(gan)侵害的(de)額外(wai)措施(shi)(shi)(shi)之(zhi)一(yi)。
Currently, egg-laying birds in Asia, including China are already vaccinated against AI, but the vaccine has not been approved in the EU yet. The EU is also developing and evaluating AI vaccines. The first results from a field study are promising, as they show no transmission of the virus to the vaccinated treatment group. The first pilot studies on commercial farms with vaccines are expected soon.
目前，亞洲地區（包(bao)括(kuo)中國）的(de)蛋雞已經接種了禽流(liu)感(gan)疫苗(miao)，但(dan)該疫苗(miao)尚未(wei)在(zai)歐盟獲得批(pi)準(zhun)。歐盟也在(zai)開發(fa)和評估(gu)禽流(liu)感(gan)疫苗(miao)。一項田間(jian)研(yan)究的(de)初步(bu)結果顯示出良好前景，研(yan)究表明接種疫苗(miao)組未(wei)發(fa)生病毒傳播。預計(ji)不久將(jiang)在(zai)商業(ye)化養殖場開展首批(pi)疫苗(miao)試點研(yan)究。
