Hu Ting-Song, Zhang Hai-Lin, Feng Yun, Fan Jian-Hua, Tang Tian, Liu Yong-Hua, Zhang Liu, Yin Xiao-Xiong, Chen Gang, Li Hua-Chang, Zu Jin, Li Hong-Bin, Li Yuan-Yuan, Yu Jing, Zhang Fu-Qiang, Fan Quan-Shui
Center for Disease Control and Prevention, Chengdu Military Region, 168 Daguan Road, Kunming, 650032, People's Republic of China.
The Postdoctoral Programme of Kunming General Hospital, Chengdu Military Region, Kunming, People's Republic of China.
BMC Infect Dis. 2017 May 8;17(1):331. doi: 10.1186/s12879-017-2401-1.
Yunnan Province is located in southwestern China and neighbors the Southeast Asian countries, all of which are dengue-endemic areas. In 2000-2013, sporadic imported cases of dengue fever (DF) were reported almost annually in Yunnan Province. During 2013-2015, we confirmed that a large-scale indigenous DF outbreak emerged in cities of Yunnan Province near the China-Myanmar-Laos border.
Epidemiological characteristics of DF in Yunnan Province during 2013-2015 were evaluated by retrospective analysis. A total of 232 dengue virus (DENV)-positive sera were randomly collected for sequence analysis of the capsid/premembrane region of DENV from patients with DF in Yunnan Province. The envelope gene of DENV isolates was also amplified and sequenced. Phylogenetic analyses were performed using the neighbor-joining method with the Tajima-Nei model.
Phylogenetically, all DENV-positive samples could be classified into DENV-1 genotype I and DENV-2 Asian I genotype during 2013-2015 and DENV-4 genotype I in 2015 from Ruili City; and DENV-3 genotype II in 2013 and DENV-2 Cosmopolitan genotype in 2015 from Xishuangbanna Prefecture.
Our results indicated that imported DF from patients from Laos and Myanmar was the primary cause of the DF epidemic in Yunnan Province. Additionally, DENV strains of all four serotypes were identified in indigenous cases in Yunnan Province during the same time period, while the dengue epidemic pattern observed in southwestern Yunnan showed characteristics of a hypoendemic nature: circulation of DENV-1 and DENV-2 over consecutive years.
云南省位于中国西南部，与东南亚国家接壤，这些国家均为登革热流行地区。2000 - 2013年期间，云南省几乎每年都有散发性输入性登革热病例报告。2013 - 2015年期间，我们确认在中国 - 缅甸 - 老挝边境附近的云南省城市出现了大规模本土登革热疫情。
通过回顾性分析评估2013 - 2015年云南省登革热的流行病学特征。随机收集了232份登革病毒（DENV）阳性血清，用于对云南省登革热患者的DENV衣壳/前膜区域进行序列分析。还对DENV分离株的包膜基因进行了扩增和测序。使用邻接法和Tajima - Nei模型进行系统发育分析。
在系统发育上，所有DENV阳性样本在2013 - 2015年期间可分为DENV - 1基因型I和DENV - 2亚洲I基因型，2015年来自瑞丽市的样本为DENV - 4基因型I；2013年来自西双版纳州的样本为DENV - 3基因型II，2015年为DENV - 2世界基因型。
我们的结果表明，来自老挝和缅甸患者的输入性登革热是云南省登革热疫情的主要原因。此外，同期在云南省本土病例中鉴定出了所有四种血清型的DENV毒株，而滇西南观察到的登革热流行模式呈现低流行性质的特征：DENV - 1和DENV - 2连续多年循环。
