Identification of the first case of SFTSV infection in the Hunan Province of China and epidemiological surveillance in the locality

Epidemiological characteristics and spatio-temporal aggregation of severe fever with thrombocytopenia syndrome in Jinan City, China, 2018-2022

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) has become a significant public health issue in Jinan City. However, the analysis of epidemiological characteristics and spatio-temporal clustering of SFTS in Jinan has not been studied yet.

METHODS

SFTS data from 2018-2022 in Jinan City were obtained from the China Information System for Disease Control and Prevention. Global spatial autocorrelation and local spatial autocorrelation analyses were performed using ArcGIS 10.2 software, and spatiotemporal hotspot area detection was carried out using SatScan 9.6 software.

RESULTS

Between 2018 and 2022, 680 SFTS cases were reported in Jinan City, resulting in 53 deaths and an average case fatality rate of 7.8%. 99.0% of cases occurred between April and October, 91.9% individuals were over 50 years old, and 87.79% were primarily farmers. A positive spatial correlation of SFTS in Jinan was observed (Moran's I value between 0.135-0.197, P<0.001), indicating spatial aggregation, primarily in Licheng, Zhangqiu, Laiwu, and Gangcheng districts in southeastern Jinan. Spatiotemporal scanning detected one class I and two class II aggregation areas, with the class I aggregation area (RR = 5.66, LLR = 192.547, P<0.001) locating in southeastern Jinan City, comprising 31 towns/streets, and an aggregation time from 13 May 2020 to 13 October 2022.

CONCLUSION

Spatial and temporal aggregation of SFTS is evident in Jinan. Based on the spatial and temporal distribution and epidemiological characteristics, prevention and control measures such as public education, monitoring, and training should target key populations in high-incidence epidemic areas.

Accuracy of reverse-transcription polymerase chain reaction and loop-mediated isothermal amplification in diagnosing severe fever with thrombocytopenia syndrome: A systematic review and meta-analysis

Nucleic acid molecular diagnostic technology plays an important role in the detection of severe fever with thrombocytopenia syndrome (SFTS). However, no relevant reports have been published on the accuracy of reverse-transcription polymerase chain reaction (RT-PCR) and reverse-transcription loop-mediated isothermal amplification (RT-LAMP) in the diagnosis of SFTS. Thus, we conducted a meta-analysis and systematic review to evaluate the accuracy of the two methods. On June 19, 2022, we comprehensively searched the PubMed, Embase, Cochrane Library, Web of Science, Scoups, Ovid, Proquest, China National Knowledge Infrastructure Database, Wan Fang Data, Traditional Chinese Medicine Database (Sinomed), VIP Database, and Reading Showing Database for articles on nucleic acid diagnostic techniques, such as RT-PCR and RT-LAMP, used to diagnose SFTS. Statistical analysis was performed using STATA 14.0 and Meta-Disc 1.4. Sixteen articles involving 2942 clinical blood samples were included in the analysis. RT-PCR and RT-LAMP were used as index tests, whereas RT-PCR or other detection methods were used as reference standards. The pooled values for the sensitivity, specificity, positive and negative likelihood ratios of the RT-PCR test were 0.97 (95% confidence interval [CI]: 0.92-0.99), 1.00 (95% CI: 0.98-1.00), 483.87 (95% CI: 58.04-4033.76), and 0.03 (95% CI:0.01-0.08), respectively. Those for the RT-LAMP test were 0.95 (95% CI: 0.91-0.97), 0.99 (95% CI: 0.93-1.00), 111.18 (95% CI: 13.96-885.27), and 0.05 (95% CI: 0.03-0.09), respectively. Both RT-PCR and RT-LAMP have high diagnostic value in SFTS and can be applied in different scenarios for laboratory confirmation or on-site screening.

A ten-year assessment of the epidemiological features and fatal risk factors of hospitalized severe fever with thrombocytopenia syndrome in Eastern China

Severe fever with thrombocytopenia syndrome (SFTS) virus has caused a large number of human infections since discovered in 2009. This study elucidated epidemiological features and fatal risk factors of SFTS cases accumulated up to ten years in Taizhou, a coastal prefecture of Zhejiang Province in Eastern China. A total of 188 hospitalised SFTS cases (including 40 deaths) reported to Taizhou Center for Disease Control and Prevention (CDC) during 2011–2020 were enrolled in the study. In the past decade, the annual incidence of SFTS increased over the years (P < 0.001) along with an expanding epidemic area, and the case fatality of hospitalised cases has remained high (21.3%). Although most cases occurred in hilly areas, a coastal island had the highest incidence and case fatality. The majority of cases were over the age of 60 years (72.3%), and both incidence and case fatality of SFTS increased with age. Multivariate logistic regression analysis showed that age (OR 7.47, 95% CI 1.32–42.33; P = 0.023), and haemorrhagic manifestations including petechiae (OR 7.76, 95% CI 1.17–51.50; P = 0.034), gingival haemorrhage (OR 5.38, 95% CI 1.25–23.15; P = 0.024) and melena (OR 5.75, 95% CI 1.18–28.07; P = 0.031) were significantly associated with the death of SFTS cases. Five family clusters identified were farmers, among four of which the index patients were female with a history of hypertension. Based on the study, age is a critical risk factor for incidence and case fatality of SFTS. With an increased annual incidence over the last ten years, SFTS remains a public health threat that should not be ignored. Further study is needed to look at the natural foci in the coastal islands.

Severe fever with thrombocytopenia syndrome virus: a highly lethal bunyavirus

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel bunyavirus. Since 2007, SFTS disease has been reported in China with high fatality rate up to 30%, which drew high attention from Centre for Disease Control and Prevention and government. SFTSV is endemic in the centra l and eastern China, Korea and Japan. There also have been similar cases reported in Vietnam. The number of SFTSV infection cases has a steady growth in these years. As SFTSV could transmitted from person to person, it will expose the public to infectious risk. In 2018 annual review of the Blueprint list of priority diseases, World Health Organisation has listed SFTSV infection as prioritised diseases for research and development in emergency contexts. However, the pathogenesis of SFTSV remains largely unclear. Currently, there are no specific therapeutics or vaccines to combat infections of SFTSV. This review discusses recent findings of epidemiology, transmission pathway, pathogenesis and treatments of SFTS disease.