Institute of Medical Biology, Chinese Academy of Medical Science and Peking Union Medical School, Kunming, China.
Joint Laboratory for Prevention and Control of Cross-border Transmission Disease, People's Hospital of Xishuangbanna Dai Autonomous Prefecture, Jinghong, China.
Front Cell Infect Microbiol. 2022 Jun 27;12:914289. doi: 10.3389/fcimb.2022.914289. eCollection 2022.
Co-infection of chikungunya virus (CHIKV) has been recently reported during dengue fever epidemics. However, the infection of CHIKV is often neglected due to its misdiagnosis as dengue virus (DENV) infection. In the summer of 2019 when dengue fever was epidemic, we collected 697 serum samples from febrile dengue fever-like patients in Xishuangbanna, southwestern part of China. DENV RNA was detectable in 99.42% of these patients. Notably, 88 patients (12.62%) showed the presence of CHIKV RNA, among which 86 patients were co-infected with DENV and CHIKV. We sequenced and analyzed the full genome of CHIKV virus in four out of 88 samples (two CHIKV infected and two co-infected). The results suggested that the four strains were all Asian genotype and had the highest homology (99.4%) with the SZ1239 strain (accession number MG664851) isolated in 2012 and possibly introduced from Indonesia. Further comparison with the conserved sequences in the whole genome of 47 strains of CHIKV showed that there were 13 and 15 amino acid mutants in structural proteins and non-structural proteins, respectively. The previously reported adaptive mutations of E2-W64R, E2-I211T, E2-K233E, E1-A98T, and E1-K211E occurred in the four strains of this study. In conclusion, this study reports a co-infection of CHIKV during the DENV epidemic in the city Xishuangbanna, 2019. Molecular epidemiology revealed that CHIKV identified in this study was indigenous and belongs to Asian lineage with lineage-specific mutations and some reported adaptive mutations, which is distinct from the recently reported CHIKV (East/Central/South African) in Ruili, the city next to Xishuangbanna.
基孔肯雅病毒（CHIKV）与登革热病毒（DENV）混合感染最近在登革热流行期间被报道。然而，由于 CHIKV 感染常被误诊为 DENV 感染而被忽视。2019 年夏，登革热流行期间，我们收集了中国西南部西双版纳发热登革热样患者的 697 份血清样本。这些患者中，99.42%的患者可检测到 DENV RNA。值得注意的是，88 例（12.62%）患者存在 CHIKV RNA，其中 86 例为 DENV 和 CHIKV 混合感染。我们从 88 例样本中随机选取 4 例（2 例 CHIKV 感染和 2 例混合感染）进行 CHIKV 全基因组测序和分析。结果表明，这 4 株均为亚洲基因型，与 2012 年分离的 SZ1239 株（登录号 MG664851）同源性最高（99.4%），可能从印度尼西亚传入。与 47 株 CHIKV 全基因组保守序列进一步比较显示，结构蛋白和非结构蛋白分别有 13 个和 15 个氨基酸突变。本研究中 4 株 CHIKV 出现了先前报道的 E2-W64R、E2-I211T、E2-K233E、E1-A98T 和 E1-K211E 适应性突变。综上所述，本研究报告了 2019 年西双版纳市登革热流行期间发生的 CHIKV 混合感染。分子流行病学表明，本研究中鉴定的 CHIKV 为本土株，属于亚洲谱系，具有谱系特异性突变和一些报道的适应性突变，与西双版纳市毗邻的瑞丽市最近报道的 CHIKV（东/中/南非）不同。
