Assessing the severity of emerging infections is challenging because of potential biases in case ascertainment. In the second epidemic of human infections with avian influenza A(H7N9) virus in China in 2013–14, we estimated that the risk of death among hospitalized H7N9 cases was 48% (95% credibility interval: 42%–54%). Using data on symptomatic cases identified through national sentinel influenza-like illness surveillance, we estimated that the risk of death among symptomatic H7N9 cases was 0.10% (95% credibility interval: 0.029%–3.6%). These estimates of severity were quite similar to previous estimates for the first epidemic wave of human infections with H7N9 in 2013.

Study design: This study was an experimental, controlled, animal study. Objective: This study was to determine the changes of molecular pathology in spinal cord decompression sickness (SC-DCS) based on a rabbit model of SC-DCS with the aid of an all-gene expression profile chip. Setting: Qingdao, Shandong Province, China. Methods: A gene expression profile chip containing 43 803 genes was used to compare the gene expressions in the spinal cords of four male New Zealand white rabbits in the SC-DCS and control groups, respectively. Selected differentially expressed genes were identified with quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. Results: The chip hybridization results showed that the SC-DCS group had nine upregulated and seventeen downregulated genes, compared with the control group. These genes were mainly related to inflammation, ion channels, the cell cycle, material transfer and apoptosis. The qRT-PCR results showed that parathyroid hormone and tumor necrosis factor alpha (TNF-a) genes were upregulated compared with the control group (Po0.01). However, the acyl-CoA synthetase and voltage-gated channel genes were downregulated (Po0.05). The immunohistochemical staining results confirmed that there were significantly greater expression levels of TNF-a in the spinal cord tissues of the SC-DCS group compared with the control group. Conclusions: The spinal cord lesions of SC-DCS involve multiple gene changes in the rabbit; however, the significance of these findings needs further research. Meanwhile, the gene expression profile chip results provide us with a better understanding of the pathogenesis of DCS.