Incidence Of Severe Fever With Thrombocytopenia Syndrome Research Articles

Spatial and Temporal Analysis of Severe Fever with Thrombocytopenia Syndrome in Anhui Province from 2011 to 2023.

To analyze the spatial autocorrelation and spatiotemporal clustering characteristics of severe fever with thrombocytopenia syndrome(SFTS) in Anhui Province from 2011 to 2023. Data of SFTS in Anhui Province from 2011 to 2023 were collected. Spatial autocorrelation analysis was conducted using GeoDa software, while spatiotemporal scanning was performed using SaTScan 10.0.1 software to identify significant spatiotemporal clusters of SFTS. From 2011 to 2023, 5720 SFTS cases were reported in Anhui Province, with an average annual incidence rate of 0.7131/100,000. The incidence of SFTS in Anhui Province reached its peak mainly from April to May, with a small peak in October. The spatial autocorrelation results showed that from 2011 to 2023, there was a spatial positive correlation(P < 0.05) in the incidence of SFTS in all counties and districts of Anhui Province. Local autocorrelation high-high clustering areas are mainly located in the south of the Huaihe River. The spatiotemporal scanning results show three main clusters of SFTS in recent years: the first cluster located in the lower reaches of the Yangtze River, the eastern region of Anhui Province; the second cluster primarily focused on the region of the Dabie Mountain range, while the third cluster primarily focused on the region of the Huang Mountain range. The incidence of SFTS in Anhui Province in 2011-2023 was spatially clustered.

Factors Associated With the Spatial Distribution of Severe Fever With Thrombocytopenia Syndrome in Zhejiang Province, China: Risk Analysis Based on Maximum Entropy.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was first identified in mainland China in 2009 and has been reported in Zhejiang Province, China, since 2011. However, few studies have focused on the association between ticks, host animals, and SFTS. In this study, we analyzed the influence of meteorological and environmental factors as well as the influence of ticks and host animals on SFTS. This can serve as a foundational basis for the development of strategic policies aimed at the prevention and control of SFTS. Data on SFTS incidence, tick density, cattle density, and meteorological and environmental factors were collected and analyzed using a maximum entropy-based model. As of December 2019, 463 laboratory-confirmed SFTS cases were reported in Zhejiang Province. We found that the density of ticks, precipitation in the wettest month, average temperature, elevation, and the normalized difference vegetation index were significantly associated with SFTS spatial distribution. The niche model fitted accurately with good performance in predicting the potential risk areas of SFTS (the average test area under the receiver operating characteristic curve for the replicate runs was 0.803 and the SD was 0.013). The risk of SFTS occurrence increased with an increase in tick density, and the response curve indicated that the risk was greater than 0.5 when tick density exceeded 1.4. The risk of SFTS occurrence decreased with increased precipitation in the wettest month, and the risk was less than 0.5 when precipitation exceeded 224.4 mm. The relationship between elevation and SFTS occurrence showed a reverse V shape, and the risk peaked at approximately 400 m. Tick density, precipitation, and elevation were dominant influencing factors for SFTS, and comprehensive intervention measures should be adjusted according to these factors to reduce SFTS incidence in Zhejiang Province.

Long-term effects of meteorological factors on severe fever with thrombocytopenia syndrome incidence in eastern China from 2014 to 2020: An ecological time-series study.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease with susceptibility influenced by meteorological factors. However, there is limited understanding of the delayed and interactive impacts of meteorological factors on SFTS incidence. Daily incidence data of SFTS and corresponding meteorological factors for the Jiaodong Peninsula in northeast China were collected from January 1, 2014, to December 31, 2020. Random forest regression model, based on custom search, was performed to compare the importance of meteorological factors. Generalized additive model with quasi-Poisson regression was conducted to examine the nonlinear relationships and interactive effects using penalized spline methods. A distributed lag nonlinear model with quasi-Poisson regression was constructed to estimate exposure-lag effects of meteorological factors. The most important meteorological factor was weekly mean lowest temperature. The relationship between meteorological factors and SFTS incidence revealed a nonlinear and intricate pattern. Interaction analyses showed that prolonged sunshine duration posed a climatic risk within a specific temperature range for SFTS incidence. The maximum relative risk (RR) observed under extremely low temperature (-4°C) was 1.33 at lag of 15 week, while under extremely high temperature (25°C), the minimum RR was 0.65 at lag of 13 week. The RRs associated with both extremely high and low sunshine duration escalated with an increase in lag weeks. This study underscores that meteorological factors exert nonlinear, delayed, and interactive effects on SFTS incidence. These findings highlight the importance of understanding the dependency of SFTS incidence on meteorological factors in particular climates.

Projecting spatiotemporal dynamics of severe fever with thrombocytopenia syndrome in the mainland of China.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with increasing incidence and geographic extent. The extent to which global climate change affects the incidence of SFTS disease remains obscure. We use an integrated multi-model, multi-scenario framework to assess the impact of global climate change on SFTS disease in China. The spatial distribution of habitat suitability for the tick Haemaphysalis longicornis was predicted by applying a boosted regression tree model under four alternative climate change scenarios (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) for the periods 2030-2039, 2050-2059, and 2080-2089. We incorporate the SFTS cases in the mainland of China from 2010 to 2019 with environmental variables and the projected distribution of H. longicornis into a generalized additive model to explore the current and future spatiotemporal dynamics of SFTS. Our results demonstrate an expanded geographic distribution of H. longicornis toward Northern and Northwestern China, showing a more pronounced change under the RCP8.5 scenario. In contrast, the environmental suitability of H. longicornis is predicted to be reduced in Central and Eastern China. The SFTS incidence in three time periods (2030-2039, 2050-2059, and 2080-2089) is predicted to be increased as compared to the 2010s in the context of various RCPs. A heterogeneous trend across provinces, however, was observed, when an increased incidence in Liaoning and Shandong provinces, while decreased incidence in Henan province is predicted. Notably, we predict possible outbreaks in Xinjiang and Yunnan in the future, where only sporadic cases have been reported previously. These findings highlight the need for tick control and population awareness of SFTS in endemic regions, and enhanced monitoring in potential risk areas.

Sex differences in incidence and fatality of severe fever with thrombocytopenia syndrome: A comparative study based on national surveillance data of China.

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne emerging infectious disease with an increasingly global concern. Sex difference in infectious diseases is an important public health problem. A comparative study on sex differences in SFTS incidence and fatality was conducted using all laboratory-confirmed cases in mainland China during 2010-2018. Females had significantly higher average annual incidence rate (AAIR) with a risk ratio (RR) of 1.17 (95% confidence interval [CI] 1.11-1.22; p ˂ 0.0001), but significantly lower-case fatality rate (CFR) with an odd ratio of 0.73 (95% CI 0.61-0.87; p = 0.001). The significant differences in AAIR and CFR were observed in age groups of 40-69 and 60-69 years, respectively (both p < 0.05). There was a rising incidence and declining CFR along with epidemic years. After adjusting for age, temporal and spatial distribution, agricultural setting and onset-to-diagnosis interval, the female-to-male difference in either AAIR or CFR remained significant. The underlying biological mechanisms of the sex-based differences that the females are more prone to get the disease, but less likely for a fatal outcome deserve further investigations.

Severe fever with thrombocytopenia syndrome incidence could be associated with ecotone between forest and cultivated land in rural settings of central China

Severe fever with thrombocytopenia syndrome (SFTS), an emerging tick-borne disease first reported in rural areas of central China, has become a major public health concern in endemic areas. The epidemic dynamic and ecologic factors of SFTS incidence at a village scale remain unclear. Here we analyzed the epidemiological characteristics of SFTS cases in Shangcheng County, the first reported areas of SFTS in China. A retrospective space-time cluster analysis was conducted to identify the dynamics of hotspot areas, and the negative binomial regression model was conducted to examine potential factors contributing to the incidence of SFTS at the village level. A total of 1,219 SFTS cases were reported in Shangcheng County from 2011 to 2020, with a case fatality rate of 12.0%. The median age of patients was 64 years, and 81.7% of patients were over 50 years old. Women accounted for 60.3% of all cases, and the incidence rate was significantly higher than that of men (Pearson χ2 test, P<0.001). Five spatial-temporal clusters were identified, and mostly distributed in the central part of the county. Higher risk of SFTS incidence was shown in villages with higher percentage coverages of forest and tea plantation, and higher goat density. In villages where the ratio of cultivated land area to forest land area was between 0.2 and 1.2, the risk of SFTS incidence increased significantly, with an incidence rate ratio of 1.33 (95% CI: 1.04‒1.72, p = 0.024). Our findings indicated that ecotone between forest and cultivated land might be the most important risk settings for exposure and infection with SFTS virus in endemic areas of central China. Precise identification of risk factors and high-risk areas at a suitable scale is conducive to carrying out targeted measures and improving the surveillance of the disease.

Analysis of the spatial-temporal components driving transmission of the severe fever with thrombocytopenia syndrome in Shandong Province, China, 2016-2018.

Existing models about the spatial-temporal distribution of the severe fever with thrombocytopenia syndrome (SFTS) entirely concentrate on aggregation, which provides limited knowledge to develop effective measures to control the epidemic of SFTS. This study aimed to identify the main spatial-temporal components and heterogeneity in different regions in Shandong Province, China. We applied the spatial-temporal multicomponent model to detect the spatial-temporal component values. A total of 2814 cases were reported from 2016 to 2018 in Shandong Province. The prevalence rate was 0.627 per 100,000, with an overall case fatality rate of 8.99%. SFTS cases were mostly clustered in central and eastern regions of Shandong Province. The total effect values of the autoregressive component, the spatiotemporal component and the endemic component were 0.586, 0.244 and 0.084, respectively, which demonstrated that the autoregressive component was the main factor driving the incidence of SFTS, followed by the spatiotemporal component. Gross domestic product per capita and weekly mean atmospheric pressure contributed to the incidence of SFTS with inverse effects. Obvious heterogeneity across regions for the autoregressive component and the spatiotemporal component was identified. In conclusion, the autoregressive and spatiotemporal components play a key role in driving the transmission of SFTS in Shandong Province. Based on the main component values, targeted measures should be formulated to control SFTS epidemics in different regions.

Epidemiological characteristics of severe fever with thtrombocytopenia syndrome in China, 2011-2021

Objective: To analyze the epidemiological characteristics of severe fever with thrombocytopenia syndrome (SFTS) in China from 2011 to 2021, and provide evidence for the prevention and control of SFTS. Methods: The incidence data of SFTS were collected from the National Disease Reporting Information System of Chinese Center for Disease Control and Prevention for a descriptive epidemiological analysis and Cochran-Armitage trend test was used to evaluate the association between age and the morbidity rate and case fatality rate (CFR) of SFTS. Results: From 2011 to 2021, a total of 18 902 laboratory confirmed cases of SFTS, including 966 deaths, were reported in 533 counties (districts) of 154 prefecture-level cities in 27 provinces. The annual average morbidity rate was 0.125/100 000, and the annual average CFR was 5.11%. From 2011 to 2021 the overall morbidity rate of SFTS was in increase with an average annual percentage change (AAPC) of 14.80% (P=0.001). Most cases (99.23%) occurred in 7 provinces, including Shandong, Henan, Anhui, Hubei, Liaoning, Zhejiang and Jiangsu, with 70.28% of the cases in 11 prefecture-level cities. The average annual CFRs in the 7 provinces varied greatly from 1.30% to 11.27%. In 2011, SFTS cases were reported in 108 counties (districts) of 51 prefecture-level cities in 13 provinces, but SFTS cases were reported in 277 counties (districts) of 88 prefecture-level cities in 19 provinces in 2021, the disease spread from central area to the northeast and from the west and the south. SFTS mainly occurred in summer and autumn in both southern and northern China, and 96.63% of the cases were reported from April to October, and the incidence peak was during May-June. The cases mainly occurred in age group 50-74 years (69.46%), and the deaths mainly occurred in age group ≥60 years (79.71%). Both the morbidity rate and the CFR increased with age. The morbidity rate increased from 0.040/100 000 in age group 0-4 years to 4.480/100 000 in age group ≥80 years in males (χ²=13 185.21, P<0.001) and from 0.038/100 000 in age group 0-4 years to 3.318/100 000 in age group ≥80 years in females (χ²=12 939.83, P<0.001); the CFR increased from 0.70% in age group 30-34 years to 11.58% in age group ≥80 years in males (χ²=115.70, P<0.001) and from 1.56% in age group 35-39 years to 8.98% in age group ≥80 years in females (χ²=103.42, P<0.001). Conclusion: From 2011 to 2021, the incidence of SFTS increased in China, and the spread and obvious spatiotemporal distribution of SFTS were observed. The reported CFR varied greatly with area, and both the morbidity and mortality risk were high in the elderly.

Meteorological factors and tick density affect the dynamics of SFTS in jiangsu province, China.

This study aimed to explore whether the transmission routes of severe fever with thrombocytopenia syndrome (SFTS) will be affected by tick density and meteorological factors, and to explore the factors that affect the transmission of SFTS. We used the transmission dynamics model to calculate the transmission rate coefficients of different transmission routes of SFTS, and used the generalized additive model to uncover how meteorological factors and tick density affect the spread of SFTS. In this study, the time-varying infection rate coefficients of different transmission routes of SFTS in Jiangsu Province from 2017 to 2020 were calculated based on the previous multi-population multi-route dynamic model (MMDM) of SFTS. The changes in transmission routes were summarized by collecting questionnaires from 537 SFTS cases in 2018-2020 in Jiangsu Province. The incidence rate of SFTS and the infection rate coefficients of different transmission routes were dependent variables, and month, meteorological factors and tick density were independent variables to establish a generalized additive model (GAM). The optimal GAM was selected using the generalized cross-validation score (GCV), and the model was validated by the 2016 data of Zhejiang Province and 2020 data of Jiangsu Province. The validated GAMs were used to predict the incidence and infection rate coefficients of SFTS in Jiangsu province in 2021, and also to predict the effect of extreme weather on SFTS. The number and proportion of infections by different transmission routes for each year and found that tick-to-human and human-to-human infections decreased yearly, but infections through animal and environmental transmission were gradually increasing. MMDM fitted well with the three-year SFTS incidence data (P<0.05). The best intervention to reduce the incidence of SFTS is to reduce the effective exposure of the population to the surroundings. Based on correlation tests, tick density was positively correlated with air temperature, wind speed, and sunshine duration. The best GAM was a model with tick transmissibility to humans as the dependent variable, without considering lagged effects (GCV = 5.9247E-22, R2 = 96%). Reported incidence increased when sunshine duration was higher than 11 h per day and decreased when temperatures were too high (>28°C). Sunshine duration and temperature had the greatest effect on transmission from host animals to humans. The effect of extreme weather conditions on SFTS was short-term, but there was no effect on SFTS after high temperature and sunshine hours. Different factors affect the infection rate coefficients of different transmission routes. Sunshine duration, relative humidity, temperature and tick density are important factors affecting the occurrence of SFTS. Hurricanes reduce the incidence of SFTS in the short term, but have little effect in the long term. The most effective intervention to reduce the incidence of SFTS is to reduce population exposure to high-risk environments.

A new luciferase immunoprecipitation system assay provided serological evidence for missed diagnosis of severe fever with thrombocytopenia syndrome.

Severe fever with thrombocytopenia syndrome (SFTS), caused by SFTS virus (SFTSV) infection, was first reported in 2010 in China with an initial fatality of up to 30%. The laboratory confirmation of SFTSV infection in terms of detection of viral RNA or antibody levels is critical for SFTS diagnosis and therapy. In this study, a new luciferase immunoprecipitation system (LIPS) assay based on pREN2 plasmid expressing SFTSV NP gene and tagged with Renilla luciferase (Rluc), was established and used to investigate the levels of antibody responses to SFTSV. Totally 464 serum samples from febrile patients were collected in the hospital of Shaoxing City in Zhejiang Province in 2019. The results showed that 82 of the 464 patients (17.7%) had antibody response to SFTSV, which were further supported by immunofluorescence assays (IFAs). Further, qRT-PCR and microneutralization tests showed that among the 82 positive cases, 15 patients had viremia, 10 patients had neutralizing antibody, and one had both (totally 26 patient). However, none of these patients were diagnosed as SFTS in the hospital probably because of their mild symptoms or subclinical manifestations. All the results indicated that at least the 26 patients having viremia or neutralizing antibody were the missed diagnosis of SFTS cases. The findings suggested the occurrence of SFTS and the SFTS incidence were higher than the reported level in Shaoxing in 2019, and that LIPS may provide an alternative strategy to confirm SFTSV infection in the laboratory.

Evaluating the spatial and temporal patterns of the severe fever thrombocytopenia syndrome in Republic of Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is a new infectious disease with a high mortality rate and increased incidence in Republic of Korea since the first case was reported in 2013. The average mortality rate varies by region and year but remains high in Asia. This study aimed to evaluate the spatial and temporal patterns of SFTS cases reported to the national Disease Control and Prevention Agency (KDCA). We analysed the spatial and temporal distribution of SFTS and observed changes in areas vulnerable to the disease. We analysed data concerning 1086 confirmed SFTS patients from 2013 to 2019 categorized according to the 247 district level administrative units. To better understand the epidemiology of SFTS, we carried out spatiotemporal analyses on a yearly basis and also calculated and mapped spatial clusters of domestic SFTS by global (regional) and local Moran's indices. To observe the annual changes in SFTS incidence rate, scan statistics for each city and district were calculated. The incidence rate showed significant clustering in specific regions, which reoccurred annually in some regions. In Republic of Korea, SFTS clusters have been expanding into the southern regions, with annual clusters concentrated between May and October. This pattern allows prediction of SFTS occurrences through spatiotemporal analysis, which makes it possible to guide measures of disease prevention.

Quantitative assessment on the epidemic characteristics of severe fever with thrombocytopenia syndrome virus infection in China

Severe fever with thrombocytopenia syndrome (SFTS) was first detected in China in 2009. The incidence of SFTS increases year by year, and there is no effective treatment. Considering that the reported prevalence of SFTSV infection varies from region to region, we aimed to quantitatively evaluate the epidemic characteristics of SFTSV infection in China from 2010 to 2020, including the distribution differences in infectious season, sex, age, occupation, and region. A meta-analysis framework was used to search for the related published data with keywords in electronic databases (CNKI, WanFang, CBM, and PubMed). According to the PRISMA statement, the studies that included SFTS diagnosed in China were analyzed. Furthermore, we used Revman and Stata to merge statistical effects, and used I2 and P-values for heterogeneity test and quality assessment. Eleven studies containing 4,932 cases confirmed by SFTSV infection were included in this meta-analysis. The ratio of male-to-female is 1.04 to 1. Cases were concentrated between 40 and 80 years of age (MD = 92%, 95%CI: 91%–93%). Farmers are at the highest risk of SFTSV infection (MD = 84%, 95%CI: 77%–90%). The risk of infection for consecutive period of April-August was significantly higher than the sum of the remaining months (MD = 82%, 95%CI: 78%–85%). In addition, the patient has an extensive history of exposure, including living in the mountains, exposure to ticks, livestock, mouse and the patient. We came to the conclusion that SFTSV is transmitted primarily through tick bites in China, so middle-aged and older adults living in mountains regions are at the highest risk for SFTSV infection in April through August each year.

Epidemic character and environmental factors in epidemic areas of severe fever with thrombocytopenia syndrome in Shandong Province

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging lethal tick-borne disease that has been widely prevalent in East Asia in recent years, and raised an important public health problem in China. However, a comprehensive and thorough understanding of the current SFTS epidemic areas in Shandong Province is not available. Accordingly, a descriptive analysis was applied to explore the demographic and spatio-temporal features of SFTS cases in Shandong Province from 2010 to 2015. The division between epidemic areas and non-epidemic areas was given by maximum entropy niche model (MaxEnt) based on environmental factors such as temperature and precipitation. There were 1,786 SFTS cases between 2010 and 2015 in Shandong, mainly involving middle-aged and elderly individuals (age:40–80) and farmers (84.6 %). May–October was the high-incidence period and the SFTS cases were mostly clustered in the central and eastern regions of Shandong Province. In light of MaxEnt, 3 specific environmental features between dichotomous areas were identified, including 1) most epidemic areas are covered by acidic soils (Constituent ratio: 63.8 %) while 29.1 % coverage appears in non-epidemic areas, 2) compared with non-epidemic areas, the identical kinds of agricultural areas accounted for a higher constituent ratio (64.9 % vs. 42.7 %), and 3) lower level of annual temperature in epidemic areas compared to non-epidemic areas [Median: 13.2℃ vs. 14.2℃; (25th IQR, 75th IQR): (12.5, 13.7) vs. (13.6, 14.9)]. Our study suggests middle-aged and elderly farmers are high-risk population to be focused on in future prevention and acidic soils, agricultural activities as well lower temperature that may be related to increased SFTS incidence.

Spatial-temporal characteristics of severe fever with thrombocytopenia syndrome and the relationship with meteorological factors from 2011 to 2018 in Zhejiang Province, China

BackgroundZhejiang Province has the fifth-highest incidence of severe fever with thrombocytopenia syndrome (SFTS) in China. While the top four provinces are all located in northern and central China, only Zhejiang Province is located in the Yangtze River Delta region of southeast China. This study was undertaken to identify the epidemiological characteristics of SFTS in Zhejiang from 2011 to 2018.MethodsThe epidemic data from SFTS cases in Zhejiang Province from January 2011 to December 2018 were obtained from the China Information Network System of Disease Prevention and Control. Meteorological data were collected from the China Meteorological Data Sharing Service System. A multivariate time series model was used to analyze the heterogeneity of spatial-temporal transmission of the disease. Random forest analysis was performed to detect the importance of meteorological factors and the dose-response association of the incidence of SFTS with these factors.ResultsIn total, 412 SFTS cases (49 fatal) were reported from January 2011 to December 2018 in Zhejiang Province, China. The number of SFTS cases and the number of affected counties increased year by year. The case fatality rate in Zhejiang Province was 11.89%, which was the highest in China. Elderly patients and farmers were the most affected. The total effect values of the autoregressive component, spatiotemporal component and endemic component of the model in all ranges were 0.4580, 0.0377 and 0.0137, respectively. There was obvious heterogeneity across counties for the mean values of the spatiotemporal component and the autoregressive component. The autoregressive component was obviously the main factor driving the occurrence of SFTS, followed by the spatiotemporal component. The importance scores of the monthly mean pressure, mean temperature, mean relative humidity, mean two-minute wind speed, duration of sunshine and precipitation were 10.64, 8.34, 8.16, 6.37, 5.35 and 2.81, respectively. The relationship between these factors and the incidence of SFTS is complicated and nonlinear. A suitable range of meteorological factors for this disease was also detected.ConclusionsThe autoregressive and spatiotemporal components played an important role in driving the transmission of SFTS. Targeted preventive efforts should be made in different areas based on the main component contributing to the epidemic. For most areas, early measures several months ahead of the suitable season for the occurrence of SFTS should be implemented. The level of reporting and diagnosis of this disease should be further improved.

Severe fever with thrombocytopenia syndrome virus targets B cells in lethal human infections.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever caused by a tick-borne banyangvirus and is associated with high fatality. Despite increasing incidence of SFTS and serious public health concerns in East Asia, the pathogenesis of lethal SFTS virus (SFTSV) infection in humans is not fully understood. Numbers of postmortem examinations to determine target cells of the viral infection have so far been limited. Here we showed that B cells differentiating into plasmablasts and macrophages in secondary lymphoid organs were targets for SFTSV at the end stage of lethal infection, and the majority of SFTSV-infected cells were B cell-lineage lymphocytes. In affected individuals, B cell-lineage lymphocytes with SFTSV infection were widely distributed in both lymphoid and nonlymphoid organs, and infiltration of these cells into the capillaries of the organs could be observed occasionally. Moreover, a human plasmablastic lymphoma cell line, PBL-1, was susceptible to SFTSV propagation and had a similar immunophenotype to that of target cells of SFTSV in fatal SFTS. PBL-1 can therefore provide a potential in vitro model for human SFTSV infection. These results extend our understanding of the pathogenesis of human lethal SFTSV infection and can facilitate the development of SFTSV countermeasures.

Gender Differences in Incidence and Fatality of Severe Fever with Thrombocytopenia Syndrome in China: A Comparative Study Based on National Surveillance Data

Background: Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging infectious disease, which has a substantial burden in eastern Asia and an increasingly global concern. Differences in infectious diseases between male and female individuals are an important public health problem. Methods: We used the database containing all reported SFTS cases in mainland China, and conducted systematic evaluation of gender differences in incidence and fatality in relation to age, temporal and spatial distribution, residence location and some clinical factors. Findings: A total of 15234 SFTS cases were reported during 2010-2018. Female individuals had significantly higher average annual incidence rate (AAIR) with a RR of 1·21 (95% CI 1·17-1·25; p˂0·0001), but significantly lower case fatality rate (CFR) with an OR of 0·74 (95% CI 0·63-0.85; p<0·0001). Both AAIR and CFR were age-dependent, and significant differences were observed in age groups of 40-69 and 50-69 years, respectively (all p<0·05). There was a rising incidence and declining CFR along with epidemic years. The AAIR and CFR varied greatly from province to province. However, higher AAIR and lower CFR in females were present among epidemic years and in affected provinces. After adjusting for potential confounders, the female-to-male difference in either AAIR or CFR remained significant. Interpretation: We elucidate an age-dependent gender dimorphism, in which the SFTS incidence is higher, but the fatality is lower for females. Further epidemiological and biological investigations are required to better understand the gender-specific differences for effective interventions. Funding Statement: This study was supported by Natural Science Foundation of China (81621005). Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: As this study constituted public health surveillance rather than research in human beings, ethical approval from institutional review boards was not required. All the information regarding individual persons had been anonymized in data collection.

Analysis of epidemiological characteristics of four natural-focal diseases in Shandong Province, China in 2009-2017: A descriptive analysis.

Natural-focal diseases are serious diseases that endanger human health. They threaten about 100 million people in Shandong Province, and cause illness in thousands of people each year. However, information on the epidemiological characteristics of natural-focal diseases in Shandong Province has been limited. The purpose of the study was to describe and analyze the epidemiological characteristics of natural-focal diseases in Shandong Province, 2009-2017. We describe the incidence and distribution of four natural-focal diseases in Shandong Province using surveillance data from 2009-2017. From 2009-2017, 11123 cases of four natural-focal diseases including 257 deaths were reported in Shandong Province, China. The four natural-focal diseases were severe fever with thrombocytopenia syndrome (SFTS), human granulocytic anaplasmosis (HGA), typhus, and scrub typhus. The high-risk groups of the four diseases were farmers and the elderly. The incidence rate of scrub typhus was significantly higher in females. However, this difference was not seen in the other three diseases. The four diseases were mainly clustered in the middle-southern part of Shandong Province and the Shandong Peninsula. The annual incidence of SFTS and scrub typhus increased, typhus was relatively stable, and HGA declined. However, the range of SFTS expanded, while HGA shrunk, and typhus and scrub typhus were unchanged. The epidemic period of SFTS and HGA was from May to October, typhus was from October to November, and scrub typhus was from September to November. The fatality rates of SFTS, typhus, scrub typhus, and HGA were 9.19%, 0%, 0.01%, and 2.24%, respectively. Our study described and analyzed the prevalence of natural-focal diseases in Shandong Province, and confirmed that age was closely related to the SFTS fatality rate. This study may help to improve the understanding of the prevalence of natural-focal diseases in Shandong Province in recent years and to better develop accurate prevention and control strategies for natural-focal diseases.

Forecast of severe fever with thrombocytopenia syndrome incidence with meteorological factors

Severe fever with thrombocytopenia syndrome (SFTS) is emerging and some studies reported that SFTS incidence was associated with meteorological factors, while no report on SFTS forecast models was reported up to date. In this study, we constructed and compared three forecast models using autoregressive integrated moving average (ARIMA) model, negative binomial regression model (NBM), and quasi-Poisson generalized additive model (GAM). The dataset from 2011 to 2015 were used for model construction and the dataset in 2016 were used for external validity assessment. All the three models fitted the SFTS cases reasonably well during the training process and forecast process, while the NBM model forecasted better than other two models. Moreover, we demonstrated that temperature and relative humidity played key roles in explaining the temporal dynamics of SFTS occurrence. Our study contributes to better understanding of SFTS dynamics and provides predictive tools for the control and prevention of SFTS.

Epidemiological Characteristics and Environmental Risk Factors of Severe Fever with Thrombocytopenia Syndrome in Hubei Province, China, from 2011 to 2016.

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral disease affecting hundreds of people in China each year. To better understand the epidemiological characteristics and environmental risk factors associated with the incidence of SFTS in Hubei Province, China, we conducted a retrospective epidemiological study and risk assessment of SFTS from 2011 to 2016. Although, the incidence and epidemic areas of SFTS are increasing, the fatality rate has decreased. Elderly farmers are the population most commonly infected with SFTS virus between May and July in the northeast Hubei Province, which seems to be consistent with local agricultural activities and the seasonal abundance of ticks. Spatial scanning showed that regions bordering with Xinyang City, Henan Province accounted for most of the SFTS cases in Hubei Province, and there was a significant association of SFTS incidence with temporal changes in the climate within these clusters. Multivariate modeling analysis identified density of cattle, rain-fed cropland, built-up land, temperature, and relative humidity as independent risk factors for the distribution of SFTS. Future epidemiological and serological studies are warranted to elucidate the dynamics and immunity patterns of local SFTS disease and to optimize interventions.

Pathogens and epidemiologic feature of severe fever with thrombocytopenia syndrome in Hubei province, China

To evaluate the aetiological agents and epidemiologic features of severe fever with thrombocytopenia syndrome (SFTS) in Hubei province, China, sera from patients were collected from January to December 2011. All cases occurred from April to December, and the epidemic peaked from May to August. The ages of patients ranged from 10 to 86 years (median=55years), and the incidence of SFTS increased with age. The female:male ratio of cases was 1.008:1, and 54.6% (77/141) and 1.4% (2/141) of the cases were confirmed by qPCR to be SFTSV and Hantavirus (HV) infection, respectively. No case of simultaneous infection with two or more pathogens was found. The research in this paper showed that some suspected SFTS cases are confused with HV infection due to similar symptoms. The analysis showed that the distribution of SFTSV has a marked regional aggregation in Hubei province.