Economic consequences of a scrapie outbreak in Australia

Overview \r\n The ABARES report presents estimates of the economic impact of a hypothetical outbreak of scrapie in Australia's sheep and goat population under three disease spread scenarios: • eradicable epidemic - an outbreak occurs and is successfully eradicated \r\n• managed spread - eradication is unsuccessful and spread is slowed by control measures \r\n• uncontrolled spread - without control measures in place, the disease spreads uncontrolled. \r\n\r\n ABARES also estimated the trade impacts that may result following an outbreak of scrapie. Due to uncertainty around the extent of export market disruptions, three export ban scenarios by China, Japan and the Republic of Korea were modelled - as these countries have been sensitive to outbreaks of notifiable livestock diseases in the past. \r\n\r\n The ABARES report indicates that Australia benefits significantly from remaining free of scrapie, and that in the event of an outbreak, it would also likely benefit from measures to eradicate the disease or control its spread. \r\n\r\nKey Issues \r\n Scrapie is a progressive neurodegenerative disease affecting sheep and goats. It belongs to the group of livestock diseases which includes mad cow disease (bovine spongiform encephalopathy or BSE) in cattle. Scrapie (unlike BSE) is not associated with any known human health risks. Australia is one of the few major sheep producing countries that is free of scrapie and only allows imports of live sheep or genetic material under strict conditions from selected countries. \r\n\r\n\tAustralia would benefit significantly from preventing the entry of scrapie, and from detecting it relatively early if it enters. If detected within 10 years of entry, efforts to eradicate the disease are likely to be both successful and cost effective. Eradication would likely be achieved an average of eight years after detection of the disease, but outbreaks could last up to 50 years. \r\n\r\n If detected early enough to be eradicable, modelled costs of controlling and eradicating scrapie-ncluding income losses from movement restrictions, were modest-estimated at an average of $4.7 million (in 2016 dollars). Most of the economic impact from an eradicable outbreak came from trade losses. \r\n• For example, if the outbreak led to a three-month ban on sheep meat by China and Japan, and a three-month ban on beef by Korea, the estimated trade losses would be $70 million over 10 years, of which $36 million would be lost by the beef industry. \r\n• A three-month ban on beef to Korea is based on existing agreed certification with Korea requiring Australian exporters to include an attestation that Australia is free of scrapie on export certificates for a range of beef and sheep meat products.. \r\n\r\n An eradication campaign is estimated to yield a benefit-cost ratio between 5:1 and 10:1, based on an assumed cost of $3 million to run epidemic control centres. \r\n\r\n If the disease was not detected in time to be eradicable, it would still be cost-effective for Australia to implement measures to slow the spread. ABARES estimated the cost of uncontrolled spread to be in excess of $406 million (in 2016 dollars), compared to the estimated $119 million to $150 million cost of slowing the spread.

概述
本报告由澳大利亚农业与资源经济科学局（ABARES）撰写，针对澳大利亚绵羊与山羊种群假想暴发痒病（scrapie）的三种疾病传播场景，估算其经济影响：
• 可根除型疫情：疫情暴发后成功实现根除
• 管控型传播：未能实现根除，通过防控措施减缓传播速度
• 无管控型传播：未采取任何防控措施，疾病无限制扩散

该局还估算了痒病暴发后可能产生的贸易影响。由于出口市场受冲击的程度存在不确定性，本次模型化了中国、日本及大韩民国的三项出口禁令场景——鉴于过往这些国家对法定通报家畜疾病暴发较为敏感。

该报告指出，澳大利亚维持痒病无疫状态将获得显著收益；若暴发疫情，采取疾病根除或传播管控措施也将为该国带来可观收益。

核心议题
痒病是一种会逐渐进展的神经退行性疾病，可感染绵羊与山羊。它与牛海绵状脑病（即疯牛病，BSE）同属一类家畜疾病。与疯牛病不同，目前尚无已知证据表明痒病会对人类健康构成风险。澳大利亚是少数维持痒病无疫状态的主要绵羊生产国之一，仅允许从选定国家在严格条件下进口活绵羊或遗传物质。

阻止痒病传入澳大利亚，以及在其传入后尽早检出，将为该国带来显著收益。若在传入10年内完成检出，根除该疾病的工作既有望成功，也具备成本效益。根除工作通常可在检出疾病后的平均8年内完成，但疫情可能持续最长达50年。

若检出时机足够早以实现根除，则控制并根除痒病的模拟成本（含流通限制带来的收入损失）较为温和——按2016年美元计价，平均估算为470万美元。可根除型疫情带来的大部分经济影响源自贸易损失。
• 举例而言，若疫情导致中国与日本对羊肉实施为期3个月的禁令，韩国对牛肉实施为期3个月的禁令，则10年内估算的贸易损失将达7000万美元，其中牛肉产业将损失3600万美元。
• 韩国对牛肉实施3个月禁令的设定，基于澳韩双方现有的认证协议：韩国要求澳大利亚出口商在多款牛肉及羊肉制品的出口证书中，附加澳大利亚无痒病的声明。

假设运营疫情防控中心的成本为300万美元，则根除行动的收益成本比估算介于5:1至10:1之间。

若未能及时检出疾病以实现根除，澳大利亚采取措施减缓疾病传播仍具备成本效益。澳大利亚农业与资源经济科学局估算，无管控传播的成本将超过4.06亿美元（按2016年美元计价），而减缓传播的成本估算为1.19亿至1.50亿美元。