Dengue Research Unit, Eijkman Institute for Molecular Biology, Ministry of Research, Technology, and Higher Education, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
AW Sjahranie Hospital and Department of Clinical Pathology, Faculty of Medicine, Universitas Mulawarman, Samarinda, East Kalimantan, Indonesia.
Virol J. 2019 Jul 25;16(1):93. doi: 10.1186/s12985-019-1202-0.
Dengue fever is a febrile disease caused by dengue virus (DENV), which affects people throughout the tropical and subtropical regions of the world, including Indonesia. East Kalimantan (Borneo) province suffered a dramatic increase in dengue cases in 2015 and 2016, making it the province with the second highest incidence of dengue in Indonesia. Despite this, dengue in East Kalimantan is understudied; leaving transmission dynamics of the disease in the area are mostly unknown. In this study, we investigate the factors contributing to the outbreaks in East Kalimantan.
Prospective clinical and molecular virology study was conducted in two main cities in the province, namely Samarinda and Balikpapan, in 2015-2016. Patients' clinical, hematological, and demographic data were recorded. Dengue detection and confirmation was performed using NS1-antigen and IgG/IgM antibody detection. RT-PCR was conducted to determine the serotypes of the virus. Phylogenetic analysis was performed based on envelope gene sequences.
Three hundred patients with suspected dengue were recruited. Among these, 132 (44%) were diagnosed with dengue by NS1 antigen and/or nucleic acid detection. The majority of the infections (60%) were primary, with dengue hemorrhagic fever (DHF) the predominant manifestation (71.9%). Serotyping detected all four DENV serotypes in 112 (37.3%) cases, with the majority of patients (58.9%) infected by DENV-3. Phylogenetic analysis based on envelope gene sequences revealed the genotypes of the viruses as DENV-1 Genotype I, DENV-2 Cosmopolitan, and DENV-3 Genotype I. Most virus strains were closely-related to strains from cities in Indonesia.
Our observations indicate that multiple introductions of endemic DENV from surrounding cities in Indonesia, coupled with relatively low herd immunity, were likely responsible for the outbreak of the dominant viruses. The study provides information on the clinical spectrum of the disease, together with serology, viral genetics, and demographic data, which will be useful for better understanding of dengue disease in Borneo.
登革热是由登革病毒（DENV）引起的发热性疾病，影响着世界上热带和亚热带地区的人群，包括印度尼西亚。东加里曼丹省（婆罗洲）在 2015 年和 2016 年经历了登革热病例的急剧增加，使其成为印度尼西亚登革热发病率第二高的省份。尽管如此，东加里曼丹的登革热研究仍很不足，该地区疾病的传播动态大多未知。在这项研究中，我们调查了导致东加里曼丹登革热爆发的因素。
2015 年至 2016 年，在该省的两个主要城市，即三马林达和巴厘巴板，进行了前瞻性临床和分子病毒学研究。记录了患者的临床、血液学和人口统计学数据。使用 NS1 抗原和 IgG/IgM 抗体检测法进行登革热检测和确认。通过 RT-PCR 确定病毒的血清型。基于包膜基因序列进行系统进化分析。
共招募了 300 名疑似登革热患者。其中，132 名（44%）通过 NS1 抗原和/或核酸检测确诊为登革热。大多数感染（60%）为原发性，以登革出血热（DHF）为主要表现（71.9%）。血清分型在 112 例（37.3%）病例中检测到所有 4 种 DENV 血清型，其中 58.9%的患者感染 DENV-3。基于包膜基因序列的系统进化分析显示，病毒株为 DENV-1 基因型 I、DENV-2 世界性和 DENV-3 基因型 I。大多数病毒株与印度尼西亚城市的病毒株密切相关。
我们的观察表明，来自印度尼西亚周边城市的地方性 DENV 的多次传入，加上相对较低的群体免疫力，可能是导致主要病毒爆发的原因。该研究提供了有关疾病临床谱的信息，以及血清学、病毒遗传学和人口统计学数据，这将有助于更好地了解婆罗洲的登革热疾病。
