Fabian Patricia, McDevitt James J, DeHaan Wesley H, Fung Rita O P, Cowling Benjamin J, Chan Kwok Hung, Leung Gabriel M, Milton Donald K
Work Environment Department, University of Massachusetts Lowell, Lowell, Massachusetts, United States of America.
PLoS One. 2008 Jul 16;3(7):e2691. doi: 10.1371/journal.pone.0002691.
Recent studies suggest that humans exhale fine particles during tidal breathing but little is known of their composition, particularly during infection.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted a study of influenza infected patients to characterize influenza virus and particle concentrations in their exhaled breath. Patients presenting with influenza-like-illness, confirmed influenza A or B virus by rapid test, and onset within 3 days were recruited at three clinics in Hong Kong, China. We collected exhaled breath from each subject onto Teflon filters and measured exhaled particle concentrations using an optical particle counter. Filters were analyzed for influenza A and B viruses by quantitative polymerase chain reaction (qPCR). Twelve out of thirteen rapid test positive patients provided exhaled breath filter samples (7 subjects infected with influenza B virus and 5 subjects infected with influenza A virus). We detected influenza virus RNA in the exhaled breath of 4 (33%) subjects--three (60%) of the five patients infected with influenza A virus and one (14%) of the seven infected with influenza B virus. Exhaled influenza virus RNA generation rates ranged from <3.2 to 20 influenza virus RNA particles per minute. Over 87% of particles exhaled were under 1 microm in diameter.
These findings regarding influenza virus RNA suggest that influenza virus may be contained in fine particles generated during tidal breathing, and add to the body of literature suggesting that fine particle aerosols may play a role in influenza transmission.
近期研究表明，人类在潮式呼吸过程中会呼出细颗粒物，但对其成分了解甚少，尤其是在感染期间。
方法/主要发现：我们对流感感染患者进行了一项研究，以确定其呼出气体中的流感病毒和颗粒浓度。在中国香港的三家诊所招募了出现流感样疾病、通过快速检测确诊为甲型或乙型流感病毒且发病在3天内的患者。我们将每个受试者的呼出气体收集到特氟龙滤器上，并使用光学粒子计数器测量呼出颗粒浓度。通过定量聚合酶链反应（qPCR）分析滤器中的甲型和乙型流感病毒。13名快速检测呈阳性的患者中有12名提供了呼出气体滤器样本（7名感染乙型流感病毒，5名感染甲型流感病毒）。我们在4名（33%）受试者的呼出气体中检测到流感病毒RNA——5名感染甲型流感病毒的患者中有3名（60%），7名感染乙型流感病毒的患者中有1名（14%）。呼出流感病毒RNA的生成率范围为每分钟<3.2至20个流感病毒RNA颗粒。呼出颗粒中超过87%的直径小于1微米。
这些关于流感病毒RNA的发现表明，流感病毒可能存在于潮式呼吸过程中产生的细颗粒物中，这也进一步证明了细颗粒气溶胶可能在流感传播中起作用。
