Nepal Health Research Council (NHRC), Ramshah Path, Kathmandu, Nepal.
Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal.
BMC Infect Dis. 2021 Feb 18;21(1):193. doi: 10.1186/s12879-021-05866-6.
Scrub typhus is a largely ignored tropical disease and a leading cause of undifferentiated febrile illness in the areas of tsutsugamushi triangle caused by Orientia tsutsugamushi. It is frequently diagnosed in South Asian countries, although clear epidemiological information is not available from Nepal. After the 2015 earthquake in Nepal, a sudden upsurge in scrub typhus cases was reported. The objective of this study was to investigate epidemiology of scrub typhus and its causative agents in humans, animals, and chigger mites to understand the ongoing transmission ecology.
Scrub typhus cases with confirmed diagnosis throughout the country were included in the analysis. Studies were concentrated in the Chitwan district, the site of a major outbreak in 2016. Additional nation-wide data from 2015 to 2017 available from the government database included to analyse the disease distribution by geographical mapping.
From 2015 to 2017, 1239 scrub typhus cases were confirmed with the largest outbreak occurring in 2016 with 831 (67.1%) cases. The case fatality rate was 5.7% in 2015 which declined to 1.1% in 2017. A nationwide outbreak of scrub typhus was declared as the cases were detected in 52 out of the 75 districts of Nepal. Seasonal trend was observed with a peak during August and September. In addition to the human cases, the presence of O. tsutsugamushi was also confirmed in animals (rodents) and chigger mites (Leptotrombidium imphalum) from the outbreak areas of southern Nepal.
The detection of O. tsutsugamushi in humans, animals, and chigger mites from outbreak locations and wide-spread reports of scrub typhus throughout the country consecutively for 3 years confirms the ongoing transmission of O. tsutsugamushi with a firmly established ecology in Nepal. The country's health system needs to be strengthened for systematic surveillance, early outbreak detection, and immediate actions including treatment and preventive measures.
恙虫病是一种被严重忽视的热带疾病，也是由恙虫东方体引起的恙虫病三角区未分化发热疾病的主要病因。尽管尼泊尔没有明确的流行病学信息，但该病在南亚国家经常被诊断出。尼泊尔在 2015 年地震后，突然报告了恙虫病病例的激增。本研究的目的是调查恙虫病及其在人类、动物和恙螨中的病原体的流行病学，以了解正在进行的传播生态学。
本分析纳入了全国范围内确诊的恙虫病病例。研究集中在奇特旺地区，该地区是 2016 年发生重大疫情的地点。此外，还从政府数据库中获取了 2015 年至 2017 年全国范围内的额外数据，通过地理绘图分析疾病分布。
2015 年至 2017 年，共确诊 1239 例恙虫病病例，其中 2016 年疫情最大，有 831 例（67.1%）病例。2015 年的病死率为 5.7%，2017 年下降至 1.1%。由于在尼泊尔的 75 个区中的 52 个区都发现了病例，因此宣布了全国范围内的恙虫病疫情。观察到季节性趋势，高峰期在 8 月和 9 月。除了人类病例外，还在尼泊尔南部疫情地区的动物（啮齿动物）和恙螨（印缅恙螨）中证实了恙虫东方体的存在。
恙虫病东方体在人类、动物和恙螨中从疫情地区被检测到，并且恙虫病在全国范围内连续 3 年广泛报告，证实了恙虫病东方体的持续传播，并在尼泊尔建立了牢固的生态。该国的卫生系统需要加强，以进行系统监测、早期疫情发现以及包括治疗和预防措施在内的立即行动。
