Testing Novel Interventions to Protect Workers from Airborne Infections

描述（由申请人提供）：在全球范围内，结核病（TB）是最严重的持续空气传播传染病威胁，但最近人们对流感，SARS和某些生物恐怖主义制剂的空气传播感到担忧。虽然卫生保健工作者的国内结核病传播风险已经下降，但仍高于一般人群。美国医疗、人道主义和研究工作者以及学生越来越多地接触到国外的耐药结核病。预防依赖于一系列传统控制措施，但这些措施在最需要的地方执行得很差，而且50多年来在传播控制方面没有取得真正的新进展。空气传播结核病是其他空气传播病原体的原型。由于结核分枝杆菌是一种对环境有害的空气传播病原体，减少空气传播结核病的干预措施可能对流感等环境适应性较差的病原体更有效。在我们之前的NIOSH拨款中，我们在南非建立了一个定量空气采样设施，使用耐多药（MDR）结核病作为替代空气传播微生物。我们表明，上层房间紫外线（UV）空气消毒的有效性为80%，对结核病患者使用外科口罩在减少向呼吸病房废气的高度易感哨兵豚鼠传播方面的有效性为50%。在此更新拨款申请中，我们建议使用完全相同的经过验证的定量空气采样方法来测试三种新的干预措施，以保护工人和其他建筑物居住者：1)新的，更节能的上层房间紫外线空气消毒系统，2)三甘醇（TEG）蒸汽作为安全的化学空气消毒剂，以及3)吸入阳离子盐

DESCRIPTION (provided by applicant): Globally, tuberculosis (TB) is the most serious ongoing airborne infectious threat, but there has been recent concern about the airborne spread of influenza, SARS, and certain bioterrorism agents. While the domestic risk of TB transmission for health care workers has fallen, it remains higher than the general population. US medical, humanitarian, and research workers as well as students are increasingly exposed to drug resistant TB abroad. Prevention has depended on a hierarchy of traditional control measures, but these have been poorly implemented where they are needed most, and there have been no truly novel advances in transmission controls for over 50 years. Airborne TB is a prototype for other airborne infectious agents. Because M. tuberculosis is an environmentally hearty airborne agent, interventions that reduce airborne TB are likely to be even more effective against less environmentally well-adapted agents such as influenza. In our previous NIOSH grant we established a quantitative air sampling facility in South Africa using multidrug resistant (MDR) tuberculosis as a surrogate airborne organism. We showed that upper room ultraviolet (UV) air disinfection was 80% effective and that the use of surgical masks on TB patients was 50% effective in reducing transmission to highly susceptible sentinel guinea pigs breathing exhaust air from the ward. In this renewal grant application, we propose to use exactly the same proven quantitative air sampling methods to test three novel interventions to protect workers and other building occupants: 1) a new, more energy efficient upper room UV air disinfection system, 2) triethylene glycol (TEG) vapor as a safe chemical air disinfectant, and 3) an inhaled cationic salt solution (ICSS) to reduce production of exhaled infectious droplets. We will also test the effects of high humidity on UV air disinfection and conduct exploratory molecular-based air sampling in parallel with guinea pig air sampling. A major limitation of upper room UV air disinfection is cost contributed to by the highly inefficient tightly louvered UV fixtures currently used to prevent excessive UV in the lower room. A totally new approach to upper room UV air disinfection addresses both efficacy and safety. The inhaled salt solution is isotonic saline, a prototype for several cationic salts shown to reduce the generation of airborne particles by changing the mechanical properties of the fluid normally lining the central airways. This will be the first quantitative test of the impact of inhaled cationic salts in reducing airborne infection generated by human sources. TEG vapor was extensively studied as an air disinfectant from 1941-1952 with highly encouraging experiments published in Science and other prestigious journals. The EPA has determined that it is safe for prolonged human and animal exposure at the very low levels required (parts 1:7 million per by volume), and it continues to be found today in over-the-counter disinfectant sprays. Under experimental conditions, TEG vapor proved rapidly effective against a long list of test microorganisms. New particle generating and monitoring technologies have solved other practical problems applying TEG.