Published: May 2019 |DOI: 10.1073/pnas.1902840116
Low ambient humidity impairs barrier function and innate resistance against influenza infection
Eriko Kudo, Eric Song, Laura Yockey, Tasfia Rakib, Patrick Wong, Robert Homer, Akiko Iwasaki
概括
This study set out to understand the impact of low humidity on the immune system's defences against the Influenza virus. Genetically modified mice, which resist flu infection in a similar way to humans, were used to test the effects of humidity, at either 10 or 20%RH compared to 50%RH, on flu infection.
將小鼠在20℃下在環境室中預先調節，並且濕度低或正常。然後他們被感染流感病毒並返回環境室，以便設定一段時間。
The mice were studied for their physical reactions to the virus, including temperature, weight, viral load in the respiratory system and ultimately their mortality to the virus.
The study found that mice housed at 20%RH suffered a worse disease course compared to those kept at 50%RH, with more rapid and greater weight loss, drop in body temperature and shortened survival. In fact, whereas all mice at the lower humidity died within 11 days of infection, of those that experienced 50%RH, just under half survived until the end of the experiment.
該研究表明，低濕度對免疫係統對流感病毒的防禦產生負麵影響。它停止了纖毛的有效操作，這是我們氣道中微小的毛狀結構，從氣管向下進入肺部，這使得去除汙染物。其次，它抑製細胞在受流感病毒損壞的肺部損壞的能力，以修複自己。最後，該研究表明，低濕度導致感染細胞釋放的信號性幹擾素失敗，以提高鄰近細胞，從而對抗其傳播。
The study offers insight into why the flu is more prevalent when the air is dry. “It’s well known that where humidity drops, a spike in flu incidence and mortality occurs. If our findings in mice hold up in humans, our study provides a possible mechanism underlying this seasonal nature of flu disease,” said Iwasaki.
While the researchers emphasized that humidity is not the only factor in flu outbreaks, it is an important one that should be considered during the winter season. Increasing water vapor in the air with humidifiers at home, school, work, and even hospital environments is a potential strategy to reduce flu symptoms and speed recovery, they said.
