A Refined Guinea Pig Model of Foot‐and‐Mouth Disease Virus Infection for Assessing the Efficacy of Antiviral Compounds

An antiviral containment strategy for foot‐and‐mouth disease (FMD) outbreaks could support or replace current contingency plans in case of an outbreak in Europe and could spare many healthy animals from being pre‐emptively culled. Recently, substantial progress has been made towards the development of small molecule drugs that inhibit FMD virus (FMDV) replication in vitro. For the initial in vivo evaluation of antiviral lead molecules, a refined FMDV‐infection model in guinea pigs (GP) is herewith described. This GP model was validated by demonstrating the antiviral effect of T‐1105 (an influenza virus inhibitor with reported activity against FMDV). Sixteen animals were orally administered with T‐1105 twice daily (400 mg/kg/day) for five consecutive days and inoculated intraplantarly with 100 GPID₅₀ of the GP‐adapted FMDV strain O₁ Manisa 1 h after the first administration. The efficacy of T‐1105 was compared with that of prophylactic vaccination with a highly potent double‐oil emulsion‐inactivated O₁ Manisa vaccine. Ten animals received a single, full (2 ml) cattle vaccine dose and were inoculated 3 weeks later. Fourteen T‐1105‐treated and all vaccinated GP were completely protected from generalization of vesicular lesions. At 2 dpi, viral RNA was detected in serum of 9/16 T‐1105‐treated and of 6/10 vaccinated animals. At 4 dpi, viral RNA was detected in serum, organs and oral swabs of half of the T‐1105‐treated animals and only in the serum of 1/10 of the vaccinated animals. Mean viral RNA levels in serum and organs of T‐1105‐treated and vaccinated animals were reduced compared to untreated controls (P < 0.01). T‐1105 conferred a substantial clinical and virological protection against infection with O₁ Manisa, similar to the protection afforded by vaccination. These results validate the suitability of the enhanced GP model for the purpose of initial evaluation of inhibitors of FMDV replication and illustrate the potential of selective inhibitors of viral replication to control FMD outbreaks.     

Ethics in biotechnology and biosecurity

Great advances in technology produce unique challenges. Every technology also has a dual use, which needs to be understood and managed to extract maximum benefits for mankind and the development of civilization. The achievements of physicists in the mid-20th century resulted in the nuclear technology, which gave us the destructive power of the atomic bomb as also a source of energy. Towards the later part of the 20th century, information technology empowered us with fast, easy and cheap access to information, but also led to intrusions into our privacy. Today, biotechnology is yielding life-saving and life-enhancing advances at a fast pace. But, the same tools can also give rise to fiercely destructive forces. How do we construct a security regime for biology? What have we learnt from the management of earlier technological advances? How much information should be in the public domain? Should biology, or more broadly science, be regulated? Who should regulate it? These and many other ethical questions need to be addressed.     

基于MCMC方法的生物气溶胶袭击施放源项参数反演

生物气溶胶施放源项参数反演是生物气溶胶袭击危害评估的反问题,对危害评估及应急响应具有重要指导意义.本文基于贝叶斯推理方法,利用生物传感器检测数据和正向大气扩散模型,构造似然函数,采用结合Metropolis-Hasting算法的马尔可夫链蒙特卡洛(Markov chain Monte Carlo,MCMC)抽样,对施放源位置、高度、施放剂量进行反演.统计分析表明,反演结果和初始源项参数设置吻合非常好,证明了方法的有效性.     

基于现代信息技术的生物灾难事件模拟系统研究

现代信息技术被广泛应用于生物灾难事件的应急管理。本文在简要介绍国外相关典型研究成果基础上,阐述利用现代信息技术进行生物灾难事件应急管理的基本思想,继而分析设计了生物灾难事件模拟系统的架构,对系统关键模型,如城市地理模型、人群活动模型、人际交互模型、个体感染模型等进行了探讨,并构建了生物灾难事件模拟原型系统。本研究为构建综合性的生物灾难事件应急管理信息系统打下基础,为事件的应急防控提供计算实验平台。     

Economic appraisal of Sirex Wood Wasp (Sirex noctilio) control in Australian pine plantations

Sirex noctilio (Sirex) is an exotic wood wasp and a pest of Pinus that has been in Australia for 65 years. Our study quantified expenditure on Sirex control between 1952 and 2014 through the National Sirex Control program, and costed the impact of three major outbreaks where large-scale tree mortality occurred. We estimate the combined cost of the program and the outbreaks at $34.5 million (net present value using a 1952 baseline and a 5% discount rate). Expenditure on the program was estimated at $24.8 million, while the combined plantation timber losses from the three studied outbreaks — Pittwater, Delatite and the Green Triangle — were valued at $9.7 million. Much higher expenditure values were generated when discounting was limited to the year that the outbreaks commenced. The outbreak at Pittwater, Tasmania commenced in 1952 and had estimated losses of $5.7 million or $5161 ha^?1. This outbreak provided the best insight into the potential of Sirex to impact timber values under a ‘no control’ scenario. The Sirex outbreak in the Green Triangle, which commenced in 1987, was costed at $21.6 million. It was Australia’s largest outbreak and occurred at a time when proven control methods were available. Study of the National Sirex Control program highlights the threats that exotic pests pose to Pinus plantations in Australia. Where realised, these threats can translate to major timber loses and costly control programs.     

An analysis of pest risk and potential economic impact of pine wilt disease to Pinus plantations in Australia

Pine wilt disease, caused by the Bursaphelenchus xylophilus (pinewood nematode), has caused extensive damage to Pinus forests where it has invaded countries with susceptible hosts and with co-occurring native species of the cerambycid beetle Monochamus. A pest risk analysis showed that there is a moderate likelihood of pinewood nematode and its primary vector, M. alternatus (Japanese pine sawyer beetle), arriving, establishing and spreading in Australia, and impacting Pinus plantations. Based on our climatic analysis, subtropical and Mediterranean climates in Australia are moderately-to-highly likely to be suitable for M. alternatus, but temperate regions may not be suitable. We present a scenario where pine wilt disease establishes in commercial Pinus plantations in south-east Queensland, spreads and causes significant tree mortality. The economic analysis suggested substantial losses in plantation timber revenue arising from tree mortality due to pine wilt disease, even at low probabilities of establishment and low rates of spread and mortality. For example, assuming chance of establishment is 5% y^?1, spread rate is 1 km y^?1, tree mortality rate is 20% and a 5% discount rate, the expected present value of plantation timber revenue losses in south-east Queensland is AU$6.9 million. This translates into high expected benefits from biosecurity programs, and indicates that it would be economically efficient to spend up to AUPine wilt disease, caused by the Bursaphelenchus xylophilus (pinewood nematode), has caused extensive damage to Pinus forests where it has invaded countries with susceptible hosts and with co-occurring native species of the cerambycid beetle Monochamus. A pest risk analysis showed that there is a moderate likelihood of pinewood nematode and its primary vector, M. alternatus (Japanese pine sawyer beetle), arriving, establishing and spreading in Australia, and impacting Pinus plantations. Based on our climatic analysis, subtropical and Mediterranean climates in Australia are moderately-to-highly likely to be suitable for M. alternatus, but temperate regions may not be suitable. We present a scenario where pine wilt disease establishes in commercial Pinus plantations in south-east Queensland, spreads and causes significant tree mortality. The economic analysis suggested substantial losses in plantation timber revenue arising from tree mortality due to pine wilt disease, even at low probabilities of establishment and low rates of spread and mortality. For example, assuming chance of establishment is 5% y^?1, spread rate is 1 km y^?1, tree mortality rate is 20% and a 5% discount rate, the expected present value of plantation timber revenue losses in south-east Queensland is AU$6.9 million. This translates into high expected benefits from biosecurity programs, and indicates that it would be economically efficient to spend up to AU$0.345 million y^?1 on biosecurity to keep pine wilt disease from establishing in south-east Queensland.     

Cost Implications of African Swine Fever in Smallholder Farrow‐to‐Finish Units: Economic Benefits of Disease Prevention Through Biosecurity

African swine fever remains the greatest limitation to the development of the pig industry in Africa, and parts of Asia and Europe. It is especially important in West and Central African countries where the disease has become endemic. Biosecurity is the implementation of a set of measures that reduce the risk of infection through segregation, cleaning and disinfection. Using a 122‐sow piggery unit, a financial model and costing were used to estimate the economic benefits of effective biosecurity against African swine fever. The outcomes suggest that pig production is a profitable venture that can generate a profit of approximately US$109 637.40 per annum and that an outbreak of African swine fever (ASF) has the potential to cause losses of up to US$910 836.70 in a single year. The implementation of biosecurity and its effective monitoring can prevent losses owing to ASF and is calculated to give a benefit‐cost ratio of 29. A full implementation of biosecurity will result in a 9.70% reduction in total annual profit, but is justified in view of the substantial costs incurred in the event of an ASF outbreak. Biosecurity implementation is robust and capable of withstanding changes in input costs including moderate feed price increases, higher management costs and marginal reductions in total outputs. It is concluded that biosecurity is a key to successful pig production in an endemic situation.     

数学在生物安全中的应用

用数学建模的方法对生物事件进行抽象,揭示其发生发展机制,可以使人们更深刻认识生物事件成灾规律,从而为生物事件的应急准备和有效处置提供更为精准的科学支持,对国家生物防御能力建设具有重要意义。该文概析了数学理论作为研究与分析工具在生物防御领域中的应用,展望了该领域研究发展趋势。