Indian Council of Medical Research-National Institute of Virology, Bangalore unit, Bangalore India.
Indian Council of Medical Research-National Institute of Virology, Pune, India.
Infect Dis (Lond). 2024 Feb;56(2):145-156. doi: 10.1080/23744235.2023.2282042. Epub 2023 Dec 18.
In this study, we carried out an investigation of Kyasanur Forest Disease (KFD) suspected human cases reported in Karnataka state, India from December 2018 to June 2019.
The clinical samples of KFD suspected cases ( = 1955) from 14 districts of Karnataka were tested for KFD using real-time RT-PCR and IgM ELISA. Further, the KFD-negative samples were tested for IgM antibodies against dengue and chikungunya viruses. Monkey samples ( = 276) and tick pools ( = 11582) were also screened using real-time RT-PCR. KFD-positive samples were further analysed using next-generation sequencing along with clinico-epidemiological analysis.
Of all, 173 (8.8%) cases tested positive for KFD either by real-time RT-PCR ( = 124), IgM ELISA ( = 53) or both tests ( = 4) from seven districts. Among KFD-negative cases, IgM antibody positivity was observed for dengue (2.6%), chikungunya (5.8%), dengue and chikungunya coinfection (3.7%). KFD cases peaked in January 2019 with fever, conjunctivitis, and myalgia as the predominant symptoms and a mortality of 4.6%. Among confirmed cases, 41% received a single dose and 20% received two doses of the KFD vaccine. Of the seven districts with KFDV positivity, Shivamogga and Hassan districts reported KFD viral RNA positivity in humans, monkeys, and ticks. Sequencing analysis of 2019 cases demonstrated a difference of less than 1.5% amino acid compared to prototype KFDV.
Although the KFD has been endemic in many districts of Karnataka state, our study confirms the presence of KFDV for the first time in two new districts, i.e. Hassan and Mysore. A comparative analysis of KFDV infection among the KFD-vaccinated and non-vaccinated populations demonstrated an insignificant difference.
本研究对 2018 年 12 月至 2019 年 6 月印度卡纳塔克邦报告的疑似基孔肯雅热（KFD）人类病例进行了调查。
采用实时 RT-PCR 和 IgM ELISA 对来自卡纳塔克邦 14 个区的 1955 例 KFD 疑似病例的临床样本进行 KFD 检测。此外，还对 KFD 阴性样本进行了登革热和基孔肯雅热病毒 IgM 抗体检测。使用实时 RT-PCR 对 276 只猴子样本和 11582 只蜱虫样本进行了筛选。对 KFD 阳性样本进行了下一代测序和临床流行病学分析。
共有 7 个区的 173 例（8.8%）病例通过实时 RT-PCR（ = 124）、IgM ELISA（ = 53）或两种检测（ = 4）呈 KFD 阳性。在 KFD 阴性病例中，登革热（2.6%）、基孔肯雅热（5.8%）和登革热和基孔肯雅热混合感染（3.7%）存在 IgM 抗体阳性。KFD 病例于 2019 年 1 月达到高峰，主要症状为发热、结膜炎和肌痛，死亡率为 4.6%。在确诊病例中，41%的患者接受了一剂 KFD 疫苗，20%的患者接受了两剂 KFD 疫苗。在 KFDV 阳性的 7 个区中，Shivamogga 和 Hassan 区报告了人类、猴子和蜱虫中 KFD 病毒 RNA 阳性。对 2019 年病例的测序分析表明，与原型 KFDV 相比，氨基酸差异小于 1.5%。
尽管 KFD 一直在卡纳塔克邦的许多地区流行，但我们的研究首次证实，在哈桑和迈索尔这两个新的地区存在 KFDV。对 KFD 疫苗接种人群和非接种人群的 KFDV 感染进行比较分析，结果无显著差异。
