幼稚園中流行性感冒病毒濃度評估

Concentration Profile of Influenza Virus in Day Care Centers

李宜璉(Yi-Lien Lee)

指導教授 ： 陳培詩

高雄醫學大學/健康科學院/公共衛生學研究所/碩士(2008年)

摘要

近來研究顯示曾引發世界上死傷慘重以及跨國間大流行疫情的流行性感冒病毒好發於參與幼稚園年齡層孩童，提出幼稚園環境為罹患流感病毒的危險因子，在過去一系列研究也證實人類不同呼吸事件中會有致病性氣膠存在，因此本研究建立鐵氟龍濾紙（Teflon Filters）輔以即時定量聚合酵素反應（real-time Quantitative, real-time qPCR）此敏感度與特異度均佳的及早病毒偵測系統，瞭解藉由氣膠方式進行人傳人之傳播的流感病毒在以自然與機械通風方式為主的兩間幼稚園空氣中四季濃度變化以及在孩童呼出氣體中之濃度分佈，在進行流感病毒濃度評估期間也同時對於所監測之幼稚園環境進行空氣品質評估。
本研究為世界上首次成功定量室內空氣中以及呼出氣體裡流感病毒濃度分佈之研究，室內空氣中流感病毒整體陽性率以冬季最高，顯著高於其他季節，而其濃度則在夏季期間因孩童高感冒盛行率而導致流感病毒濃度顯著高於其他季節。空氣品質採樣項目在四季間也都具有顯著的季節變化，空氣中可培養性細菌與真菌在夏季時濃度顯著高於其他季節，室內一氧化碳、二氧化碳與奈米懸浮微粒顆粒數均在冬季時濃度顯著高於其他季節。兩間不同通風環境中流感病毒陽性率與其濃度皆與室內溫度有顯著負線性關係以及與室內一氧化碳濃度有正向線性關係產生，同時也發現空氣中A型流感病毒濃度與兩間幼稚園孩童感冒盛行率有顯著線性關係。此外兩間幼稚園空氣中可培養性細菌濃度分佈皆高於室內空氣品質建議值7－11倍以上，在自然通風環境的幼稚園空氣中可培養性真菌濃度也很高，真菌濃度多與孩童過敏引發有相關值得留意，而在機械通風環境的幼稚園裡室內一氧化碳與二氧化碳濃度四季不合格率結果為100％，孩童長期暴露室內通風情形不佳場是否會有健康上影響應進一步觀察。
本研究所建立的呼出氣體流感病毒偵測方式在與問卷方式詢問孩童是否經醫師診斷罹患感冒兩者間具有中度一致性，此外也能有效在潛伏期時即偵測並定量病毒濃度，掌握感冒發病前後流感病毒濃度變化情形，觀察到年齡層越大的孩童在感冒期間能呼出病毒的日數少於年齡層較小者；同時也發現孩童呼出氣體流感病毒濃度與空氣中流感病毒陽性率分佈有正相關的現象。

關鍵字

室內空氣品質 ； 幼稚園 ； 流行性感冒病毒 ； 呼出氣體

並列摘要

Day care attendance is considerable risk factor of influenza infection among children. Thus, early characterization for airborne influenza virus in high risk environment is of extreme importance. In addition, exhaled aerosol may carry airborne pathogens and play an important role for infectious diseases outbreak. Therefore, the purpose of present study is to investigate the airborne influenza virus of two day care centers with different ventilation system during four seasons, the air quality of two centers were also monitored simultaneously. Furthermore, influenza virus in exhaled air was also studied to understand the profiles of different disease status, and different host age in this present study. To our knowledge, this is the first study regarding quantifying the concentration of airborne influenza virus in day care centers, either did assess influenza virus in exhaled air of infected children.
The concentration profile of airborne influenza virus was successfully characterized by filter with real-time qPCR assay in day care centers during Spring, Summer, Fall, and Winter, respectively. It was demonstrated that the positive rate of influenza virus in winter of two centers was significantly higher than other seasons, although the concentration of airborne influenza virus was significantly higher in summer due to the higher flu-like disease prevalence. In regard to the seasonal trend of other indoor pollutants, the concentration of total airborne cultivable bacteria and fungi was significantly higher in summer, but the concentration of carbon monoxide, carbon dioxide and number of ultra fine particle were highest in winter. In regard to the correlation between influenza virus and environmental factors, the positive rate of airborne influenza A virus and influenza B virus have an negative correlation with indoor temperature. In addition, it was also found out that the positive rate of influenza A virus and influenza B virus were all positively correlated with the concentration of indoor carbon monoxide regardless the difference of ventilation system. Furthermore, the concentration of airborne influenza A virus in both day care centers was positively correlated with the cold prevalence of children. In comparison with the Indoor Air Quality Recommended Values of Taiwan Environmental Protection Administration, the airborne cultivable bacteria concentration in both centers was 7－11 fold higher than the recommended value, and the failure rate of carbon monoxide and carbon dioxide was exceed fifty percentage.
An exhaled aerosol sampling device, developed in the present study, was demonstrated to provide an easy, noninvasive method to characterize the concentration of influenza virus in exhaled air. We have revealed the influenza virus could be exhaled during the latency period, and the concentration was increased when subject suffered cold symptom. It was also demonstrated that the older subject among five to six, the less virus could be exhaled. In addition, the concentration of influenza virus in exhaled air has a significantly positive correlation with the positive rate of airborne influenza virus.
In conclusion, we successfully demonstrated that the filter with real-time qPCR is a very sensitive and fast method to quantify airborne influenza virus in day care centers and in exhaled air of infected children. Airborne influenza virus was negatively correlated with temperature and positively correlated with carbon monoxide and other environmental factors were also investigated. In addition, airborne influenza virus was positively correlated with the number of infected children. Furthermore, profile of influenza virus during the whole disease period was also demonstrated.

並列關鍵字

Influenza virus ； day care center ； air quality ； exhaled air

參考文獻

參 考 文 獻

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