ABSTRACT
This study aimed to evaluate the etiological and clinical characteristics of acute upper respiratory tract infections in children from GuangZhou, China. A total of 2 665 nose swabs specimen collected from children with acute upper respiratory tract infections from Zhujiang Hospital, Southern Medical University, Guangzhou, China during November 2009 to September 2015 were enrolled in this study. There were 1 566 virus positive responses were detected in samples from 2665 child patients with acute upper respiratory infections, with the positive rate of 58.8%. The positive rates were 22.5% for respiratory sycytial virus (RSV), 13.0% for rhinovirus (HRV), 9.0% for influenza virus (FLU), 7.6% for parainfluenza virus (PIV), 6.1% for adenovirus (AdV), 4.0% for human metapneumovirus (HMPV), 3.7% for human coronavirus (HCOV), 3.5% for human Bocavirus (HBOV). There was statistical significant in the detection rates of 8 respiratory viruses in different seasons, with the highest in spring, followed by summer and winter, and lowest in autumn. The respiratory virus infection rate of children gradually decreased with age, with a positive detection rate of 67.0% between children aged 0-3 years. And the respiratory virus detection rate of boys was significantly higher than that of girls. The co-infection rates were higher in child patients aged 0-3 years, and were higher during spring and summer than that of autumn and winter. Cough is the main clinical symptom of acute upper respiratory virus infection, followed by sputum and runny nose. The clinical symptoms are different in children between 8 respiratory virus infections. This study increases our knowledge of the etiological and clinical characteristics of these 8 common respiratory viruses among children with respiratory tract infections. Which might also provide relevant data to guide clinical treatment and prevention.
ABSTRACT
The objective of this study is to understand the effect of indoor air stability on personal exposure to infectious contaminant in the breathing zone. Numerical simulations are carried out in a test chamber with a source of infectious contaminant and a manikin (Manikin A). To give a good visual illustration of the breathing zone, the contaminant source is visualized by the mouth of another manikin. Manikin A is regarded as a vulnerable individual to infectious contaminant. Exposure index and exposure intensity are used as indicators of the exposure level in the breathing zone. The results show that in the stable condition, the infectious contaminant proceeds straightly towards the breathing zone of the vulnerable individual, leading to a relatively high exposure level. In the unstable condition, the indoor air experiences a strong mixing due to the heat exchange between the hot bottom air and the cool top air, so the infectious contaminant disperses effectively from the breathing zone. The unstable air can greatly reduce personal exposure to the infectious contaminant in the breathing zone. This study demonstrates the importance of indoor air stability on personal exposure in the indoor environment and provides a new direction for future study of personal exposure reduction in the indoor environment.