Defence R&D Canada - Suffield, Medicine Hat, Alberta, Canada.
J Occup Environ Hyg. 2010 Feb;7(2):71-9. doi: 10.1080/15459620903389558.
This report is the first detailed and quantitative study of potential mitigation procedures intended to deal with anthrax letters using a simulated anthrax letter release within an actual office building. Spore aerosols were created by opening letters containing 0.1 g of dry powdered Bacillus atrophaeus spores. Culturable aerosol samples were collected using slit-to-agar and filter-based samplers. Five test scenarios were designed to determine whether simple mitigation procedures or activities carried out by the person who opened the letter made a significant difference to aerosol concentrations in comparison to a control scenario where no activity took place. Surface contamination of the letter opener was measured at 10 body points for Scenarios 1 to 4. A sixth scenario, based on published Centers for Disease Control and Prevention anthrax letter response guidelines, used letters containing 1 g of spores. Results demonstrated that the spore aerosol spread throughout the building in less than 4.5 min. Potential mitigation techniques such as closing the office door or shutting off the ventilation system were not effective. Activities carried out by the letter opener including moving, walking to another location, and spraying water onto the contaminated desk with a hand sprayer all resulted in significantly higher aerosol concentrations in comparison to control. The potential total inhalational hazard for the letter opener during the five test scenarios ranged from 4.1 x 10(5) to 1.6 x 10(6) colony forming units (CFU) compared to 3.9 x 10(5) CFU for the control. Surface contamination of the letter opener (Scenarios 1 to 4) was highest on the right hip (4.8 x 10(4) to 1.0 x 10(5) CFU/cm(- 2)) and lowest on the right or left side of the head (2.2 x 10(2) to 3.7 x 10(3) CFU/cm(-2)). The statistically based methodology used in this study provided the means to objectively assess anthrax letter protocols to determine their effectiveness under realistic conditions. Potential mitigation procedures tested in this study did not reduce aerosol hazard or surface contamination.
本报告是首次详细和定量地研究旨在使用实际办公大楼内模拟炭疽信件释放来处理炭疽信件的潜在缓解程序。通过打开含有 0.1 克干燥粉状萎缩芽孢杆菌孢子的信件来产生孢子气溶胶。使用狭缝到琼脂和基于过滤器的采样器收集可培养气溶胶样本。设计了五个测试场景，以确定与未发生任何活动的对照场景相比，简单的缓解程序或打开信件的人进行的活动是否对气溶胶浓度有显著影响。对场景 1 到 4 中的 10 个身体部位进行了信刀表面污染测量。第六个场景基于已发布的疾病控制和预防中心炭疽信件应对指南，使用含有 1 克孢子的信件。结果表明，孢子气溶胶在不到 4.5 分钟的时间内扩散到整个建筑物中。关闭办公室门或关闭通风系统等潜在缓解技术没有效果。信刀的活动，包括移动、走到另一个位置以及用手动喷雾器将水喷到受污染的桌子上，与对照相比，都导致气溶胶浓度显著升高。在五个测试场景中，信刀的潜在总吸入危险范围从 4.1 x 10(5)到 1.6 x 10(6)个集落形成单位 (CFU)，而对照为 3.9 x 10(5) CFU。信刀（场景 1 到 4）的表面污染最高在右臀部（4.8 x 10(4)到 1.0 x 10(5) CFU/cm(-2))，最低在头部的右侧或左侧（2.2 x 10(2)到 3.7 x 10(3) CFU/cm(-2))。本研究中使用的基于统计学的方法提供了客观评估炭疽信件协议的手段，以确定其在现实条件下的有效性。本研究中测试的潜在缓解程序并没有降低气溶胶危害或表面污染。
