Dataset Information

Epidemiological Characterization of the 2017 Dengue Outbreak in Zhejiang, China and Molecular Characterization of the Viruses.

ABSTRACT: Dengue, a mosquito-borne disease caused by the dengue virus (DV), has been recognized as a global public health threat. In 2017, an unexpected dengue outbreak occurred in Zhejiang, China. To clarify and characterize the causative agent of this outbreak, data on dengue fever cases were collected from the China Information System for Disease Control and Prevention in Zhejiang province for subsequent epidemiological analysis. A total of 1,229 cases were reported, including 1,149 indigenous and 80 imported cases. Most indigenous cases (1,128 cases) were in Hangzhou. The epidemic peak occurred in late August and early September, and the incidence rate of elderly people (4.34 per 100,000) was relatively high. Imported cases were reported all year round, and most were from South-East Asia and Western Pacific regions. Young people and men accounted for a large fraction of the cases. Acute phase serums of patients were collected for virus isolation. And 35 isolates (including 25 DV-2, 8 DV-1, 1 DV-3, and 1 DV-4) were obtained after inoculation and culture in mosquito C6/36 cells. The E genes of the 35 new DV isolates and the complete genome of a DV-2 isolate (Zhejiang/HZ33/2017), and the E gene of a DV-2 isolate from Ae. albopictus (Zhejiang/Aedes-1/2017) were determined. Phylogenetic analyses were performed using the neighbor-joining method with the Tajima-Nei model. Phylogenetically, DVs of all four serotypes with multiple genotypes (mainly including 21 Cosmopolitan genotype DV-2, 4 Asian I genotype DV-2, 6 genotype I DV-1, and 2 genotype V DV-1) were present in the indigenous and imported cases in Zhejiang during the same period. Most of the isolates probably originated from South-East Asia and Western Pacific countries. The imported cases, high density of mosquito vector, and missed diagnosis might contribute to the 2017 outbreak in Zhejiang.

SUBMITTER: Yan H

PROVIDER: S-EPMC6039557 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Epidemiological Characterization of the 2017 Dengue Outbreak in Zhejiang, China and Molecular Characterization of the Viruses.

Yan Hao H Ding Zheyuan Z Yan Juying J Yao Wenwu W Pan Junhang J Yang Zhangnv Z Lou Xiuyu X Mao Haiyan H Lin Junfen J Sun Jimin J Hou Juan J Wu Haocheng H Wu Chen C Zhang Yanjun Y

Frontiers in cellular and infection microbiology 20180704

Dengue, a mosquito-borne disease caused by the dengue virus (DV), has been recognized as a global public health threat. In 2017, an unexpected dengue outbreak occurred in Zhejiang, China. To clarify and characterize the causative agent of this outbreak, data on dengue fever cases were collected from the China Information System for Disease Control and Prevention in Zhejiang province for subsequent epidemiological analysis. A total of 1,229 cases were reported, including 1,149 indigenous and 80 i ...[more]

PMID: 30023351

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Project description:BackgroundDengue is one of the most important vector-bore infectious diseases in China because of its drastic increase in incidence, geographic extension and profound influence on China's economy. This study aims to retrospectively uncover the epidemiological profile of dengue in Zhejiang, one of the most developed provinces in China, and to find the problem existing in dengue control and prevention.MethodologyDescriptive analyses on the dengue incidence and associated factors were performed. We also identified potential space-time cluster and generated the risk map of dengue.Principal findingsA total of 529 cases were reported in Zhejiang Province from 2005 to 2016, and 44.4% were imported. 67.7% of cases were 25~60 years old and the overall male-to-female sex ratio was 1.09:1. Dengue was reported all year round and 70.7% of cases occurred between August and October. Indigenous cases were only reported in the period between July to November and more than half occurred in September. Geographically, dengue was most distributed in Jinghua (3.62 per million), Shaoxing (1.00 per million) and Taizhou (0.81 per million) prefecture level cities. Outbreaks were confirmed in Yiwu, Keqiao and Huangyan counties in 2009, 2015, and 2016, respectively. 73.9% cases would seek medical advice within two days after onset and be confirmed within 9 days after onset. 75.6% would be recognized as dengue within 8 days after their first visit. The time intervals between onset and confirmation (median 7 vs 6 days; Wilcoxon rank sum test Z = -2.40, P = 0.016), first visit and confirmation (median 7 vs 6 days; Wilcoxon rank sum test Z = -2.59, P = 0.009) of indigenous cases were significantly longer than those of imported ones. However, the time intervals between onset and first visit for indigenous cases was shorter (median 0 vs 1 days; Wilcoxon rank sum test Z = -2.10, P = 0.036). Fever (99.1%), fatigue (81.9), rash (63.7%), headache (67.2%) and myalgia (52.60%) were the most frequently mentioned symptoms.ConclusionsZhejiang has recently witnessed an increase in incidence and geographic extension of dengue. Timely diagnosis is important to stop local transmission and outbreak.

Project description:In 2015, a dengue outbreak with 1,067 reported cases occurred in Xishuangbanna, a city in China that borders Burma and Laos. To characterize the virus, the complete genome sequence was obtained and phylogenetic, mutation, substitution and recombinant analyses were performed. DENV-NS1 positive serum samples were collected from dengue fever patients, and complete genome sequences were obtained through RT-qPCR from these serum samples. Phylogenetic trees were then constructed by maximum likelihood phylogeny test (MEGA7.0), followed by analysis of nucleotide mutation and amino acid substitution. The recombination events among DENVs were also analyzed by RDP4 package. The diversity analysis of secondary structure for translated viral proteins was also performed. The complete genome sequences of four amplified viruses (YNXJ10, YNXJ12, YNXJ13, and YNXJ16) were 10,742, 10,742, 10,741, and 10,734 nucleotides in length, and phylogenetic analysis classified the viruses as cosmopolitan genotype of DENV-2. All viruses were close to DENV Singapore 2013 (KX380828.1) and the DENV China 2013 (KF479233.1). In comparison to DENV-2SS (M29095), the total numbers of base substitutions were 712 nt (YNXJ10), 809 nt (YNXJ12), 772 nt (YNXJ13), and 841 nt (YNXJ16), resulting in 109, 171, 130, and 180 amino acid substitutions in translated regions, respectively. In addition, compared with KX380828.1, there were 44, 105, 64, and 116 amino acid substitutions in translated regions, respectively. The highest mutation rate occurred in the prM region, and the lowest mutation rate occurred in the NS4B region. Most of the recombination events occurred in the prM, E and NS2B/3 regions, which corresponded with the mutation frequency of the related portion. Secondary structure prediction within the 3,391 amino acids of DENV structural proteins showed there were 7 new possible nucleotide-binding sites and 6 lost sites compared to DENV-2SS. In addition, 41 distinct amino acid changes were found in the helix regions, although the distribution of the exposed and buried regions changed only slightly. Our findings may help to understand the intrinsic geographical relatedness of DENV-2 and contributes to the understanding of viral evolution and its impact on the epidemic potential and pathogenicity of DENV.

Dataset Information

Epidemiological Characterization of the 2017 Dengue Outbreak in Zhejiang, China and Molecular Characterization of the Viruses.

Publications

Epidemiological Characterization of the 2017 Dengue Outbreak in Zhejiang, China and Molecular Characterization of the Viruses.

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