Clinical Characteristics and Risk Factors for Severe Dengue Fever in Xishuangbanna, During the Dengue Outbreak in 2019

Xiaodan Wang; Tingting Li; Yun Shu; Juan Zhang; Xiyun Shan; Daiying Li; Dehong Ma; Shuying Long; Yue Pan; Junying Chen; Pinghua Liu; Qiangming Sun

doi:10.3389/fmicb.2022.739970

Clinical Characteristics and Risk Factors for Severe Dengue Fever in Xishuangbanna, During the Dengue Outbreak in 2019

Front Microbiol. 2022 Mar 10:13:739970. doi: 10.3389/fmicb.2022.739970. eCollection 2022.

Authors

Xiaodan Wang^{1

2

3}, Tingting Li⁴, Yun Shu⁴, Juan Zhang^{1

2

3

5}, Xiyun Shan⁴, Daiying Li^{1

2

3}, Dehong Ma⁴, Shuying Long⁵, Yue Pan^{1

2

3}, Junying Chen^{1

2

3}, Pinghua Liu⁴, Qiangming Sun^{1

2

3}

Affiliations

¹ Institute of Medical Biology, Chinese Academy of Medical Sciences, Peking Union Medical College, Kunming, China.
² Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Diseases, Kunming, China.
³ Yunnan Key Laboratory of Vector-Borne Infectious Disease, Kunming, China.
⁴ Xishuangbanna Dai Autonomous Prefecture People's Hospital, Jinhong, China.
⁵ Kunming Medical University, Kunming, China.

Abstract

Background: Dengue poses a large burden on the public health systems worldwide. severe dengue (SD) could lead to more serious clinical symptoms and even death. This study aimed to identify the cause of SD in a clinical trial during the dengue outbreak in Xishuangbanna in 2019, and could provide new insights into the pathogenic mechanisms of SD.

Methods: Mosquito-borne viral (DENV, JEV, and CHIKV) infections were identified. The epidemiological factors and clinical symptoms of inpatients in Xishuangbanna were recorded. The IgG and IgM levels in the serum of dengue inpatients were evaluated, and secondary infections were identified. Then, the structural proteins (C/PrM/E) were sequenced and compared with those of the same type of DENV in the same area as before, and their structures were predicted by the SWISS-MODEL (expasy.org). The full-length viral genomes were sequenced and aligned with representative strains by BioEidt or MEGA 5.0.

Results: In this outbreak, the clinical symptoms were more serious in SD. The proportion of SD inpatients of male and Han nationality was larger than that of dengue fever (DF) inpatients (p < 0.05). DENV-2 infection was the majority in DF, with 45 inpatients. However, DENV-1 infection was the most common SD, with 54 inpatients. There were 3 DENV-3-positive inpatients in the DF group and 6 ZIKV-positive inpatients in the SD group. A secondary infection accounted for 76.47% (78 cases) of SD inpatients, but secondary infections were only in 20% (17 cases) of DF inpatients. In the three-dimensional structure of protein analysis, the C/PrM/E of DENV-1 and DENV-2 showed more stability than previous epidemic strains, while DENV-3 in 2019 showed a looser spatial structure. After a complete genome sequencing and analysis, all six DENV-2 strains belonged to cosmopolitan, five of which clustered into one branch. The GC/AT of the five strains decreased from 2014 to 2018. Compared with DF strains, SD strains had no mutations of commonness.

Conclusions: SD may related to secondary heteromorphic dengue in Xishuangbanna in 2019. The coinfection of ZIKV could be another related factor for SD. The currently datas were very limited and only suggestive.

Keywords: IgG; IgM; dengue gene sequence; dengue inpatients; severe dengue fever.