Duncan E J Scott, Kournikakis Bill, Ho Jim, Hill Ira
Defence R. & D. Canada - Suffield, Medicine Hat, Alberta, Canada.
Inhal Toxicol. 2009 Feb;21(2):141-52. doi: 10.1080/08958370802412629.
Dry anthrax spore powder is readily disseminated as an aerosol and it is possible that passive dispersion when opening a letter containing anthrax spores may result in lethal doses to humans. The specific aim of this study was to quantify the respirable aerosol hazard associated with opening an envelope/letter contaminated with a dry spore powder of the biological pathogen anthrax in a typical office environment. An envelope containing a letter contaminated with 1.0 g of dry Bacillus atrophaeus (BG) spores (pathogen simulant) was opened in the presence of an unrestrained swine model. Aerosolized spores were detected in the room in seconds and peak concentrations occurred by three minutes. The swine, located approximately 1.5 m from the source, was exposed to the aerosol for 28 min following the letter opening event and then moved to a clean room for 30 min. A necropsy was completed to determine the extent of in vivo spore deposition in the lungs. The median number of viable colony forming units (CFU) measured in the combined right and left lung was 21,200: the average mass of both lungs was 283 g. In excess of 100 CFU per gram of lung tissue was found at sites within the anterior, intermediate and posterior lobes. The results of this study confirmed that opening an envelope containing spores generated an aerosol spanning the respirable particle size range of 1-10 microm, and that normal respiration of swine led to spore deposition throughout the lungs. The observed deposition of spores in the lungs of the swine is within the LD(50) range of 2,500-55,000 estimated for humans for inhaled anthrax. Thus, there would appear to be a significant health risk to those individuals exposed to anthrax spores when opening a contaminated envelope.
干燥的炭疽芽孢粉末很容易以气溶胶形式传播，打开一封装有炭疽芽孢的信件时，被动扩散有可能导致对人类的致死剂量。本研究的具体目的是量化在典型办公环境中打开一封被生物病原体炭疽的干燥芽孢粉末污染的信封/信件时，可吸入气溶胶的危害。在一只未受限制的猪模型面前，打开一封装有被1.0克萎缩芽孢杆菌（BG）芽孢（病原体模拟物）污染信件的信封。数秒内即可在室内检测到雾化的芽孢，三分钟时出现峰值浓度。这头距离源约1.5米的猪在信件打开事件后暴露于气溶胶中28分钟，然后转移到洁净室30分钟。完成尸检以确定肺部体内芽孢沉积的程度。左右肺合并测量的存活菌落形成单位（CFU）中位数为21,200：两肺平均质量为283克。在前叶、中叶和后叶的部位发现每克肺组织超过100个CFU。本研究结果证实，打开装有芽孢的信封会产生粒径范围在1 - 10微米的可吸入气溶胶，猪的正常呼吸导致芽孢在整个肺部沉积。在猪肺部观察到的芽孢沉积处于估计人类吸入炭疽的半数致死剂量（LD50）范围2500 - 55000之内。因此，对于那些在打开受污染信封时接触炭疽芽孢的个体而言，似乎存在重大健康风险。
