Development and Performance Evaluation of an Exhaled-Breath Bioaerosol Collector for Influenza Virus.

The importance of the aerosol mode for transmission of influenza is unknown. Understanding the role of aerosols is essential to developing public health interventions such as the use of surgical masks as a source control to prevent the release of infectious aerosols. Little information is available on the number and size of particles generated by infected persons, which is partly due to the limitations of conventional air samplers, which do not efficiently capture fine particles or maintain microorganism viability. We designed and built a new sampler, called the G-II, that collects exhaled breath particles that can be used in infectivity analyses. The G-II allows test subjects to perform various respiratory maneuvers (i.e. tidal breathing, coughing, and talking) and allows subjects to wear a mask or respirator during testing. A conventional slit impactor collects particles > 5.0 μm. Condensation of water vapor is used to grow remaining particles, including fine particles, to a size large enough to be efficiently collected by a 1.0 μm slit impactor and be deposited into a buffer-containing collector. We evaluated the G-II for fine particle collection efficiency with inert particle aerosols and evaluated infective virus collection using influenza A virus aerosols. Testing results showed greater than 85% collection efficiency for particles greater than 50nm and influenza virus collection comparable with a reference SKC BioSampler®. The new design will enable determination of exhaled infectious virus generation rate and evaluate control strategies such as wearing a surgical type mask to prevent the release of viruses from infected persons.

气溶胶模式对于流感传播的重要性尚不明确。了解气溶胶的作用对于制定公共卫生干预措施至关重要，例如使用医用口罩作为源头控制措施以防止传染性气溶胶的释放。关于感染者产生的颗粒数量和大小的信息很少，部分原因是传统空气采样器的局限性，它们无法有效捕获微小颗粒或保持微生物的活性。我们设计并制造了一种新的采样器，称为G - II，它可以收集呼出的气息颗粒，用于传染性分析。G - II允许测试对象进行各种呼吸动作（即平静呼吸、咳嗽和说话），并允许测试对象在测试过程中佩戴口罩或呼吸器。传统的狭缝撞击器收集大于5.0μm的颗粒。水蒸气凝结用于使剩余的颗粒（包括微小颗粒）增长到足够大的尺寸，以便能被1.0μm的狭缝撞击器有效收集并沉积到含有缓冲液的收集器中。我们用惰性颗粒气溶胶评估了G - II对微小颗粒的收集效率，并用甲型流感病毒气溶胶评估了感染性病毒的收集情况。测试结果显示，对于大于50nm的颗粒，收集效率大于85%，流感病毒的收集情况与参考的SKC BioSampler®相当。新的设计将能够确定呼出的感染性病毒产生率，并评估诸如佩戴医用口罩等控制策略，以防止感染者释放病毒。