Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease worldwide. It can be transmitted from person to person, and the fatality rate is very high. During this study, three SFTS clusters including 12 associated cases were identified in three counties in Zhejiang Province from 2018 to 2020. The median age of the three index patients was 70 years, and that of secondary case patients was 59 years. Of note, the mortality rate of the index patients was 100%. The mortality rate of secondary case patients was 11%. The total secondary attack rate (SAR) was 30% (9/30). The SARs of cluster A, cluster B, and cluster C were 38% (3/8), 21% (3/14), and 38% (3/8), respectively. Additionally, the interval from onset to diagnosis was 4 days. The intervals from disease onset to confirmation of the index cases and secondary cases were 7 days and 4 days, respectively. All secondary case patients had a history of close contact with blood or body fluids of the index patients. These results indicate that SFTS patients should not be discharged until recovery. When SFTS patients die, the corpses should be transferred directly from the hospital to the crematorium for cremation by persons wearing proper protective equipment to prevent virus transmission.

Background Hemorrhagic fever with renal syndrome (HFRS) is endemic in Zhejiang Province, China, while few studies have concentrated on the influence of meteorological factors on HFRS incidence in the area. Methods Data on HFRS and meteorological factors from January 1, 2008 to December 31, 2020 in Taizhou City, Zhejiang Province were collected. Multivariate analysis was conducted to the relationship between meteorological factors including minimum temperatures, relative humidity, and cumulative rainfall with HFRS. Results The HFRS incidence peaked in November and December and it was negatively correlated with average and highest average temperatures. Compared with median of meteorological factors, the relative risks (RR) of weekly average temperature at 12 ℃, weekly highest temperature at 18 ℃relative humidity at 40%, and cumulative rainfall at 240 mm were most significant and RRs were 1.41 (95% CI: 1.09–1.82), 1.32 (95% CI: 1.05–1.66), 2.18 (95% CI: 1.16–4.07), and 1.91 (95% CI: 1.16–2.73), respectively. Average temperature, precipitation, relative humidity had interactions on HFRS and the risk of HFRS occurrence increased with the decrease of average temperature and the increase of precipitation. Conclusion Our study results are indicative of the association of environmental factors with the HFRS incidence, probable recommendation could be use of environmental factors as early warning signals for initiating the control measure and response.

IntroductionSevere fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease, and the number of cases has increased in recent years in Zhejiang Province, China. However, whether the seasonal distribution, geographic distribution, and demographic characteristics of SFTS have changed with the increase of incidence was unclear.Materials and MethodsData on SFTS cases in Zhejiang Province and tick density in Daishan County from 2011 to 2019 were collected. The changing epidemiological characteristics of SFTS including seasonal distribution, geographical distribution, and demographic features were analyzed using descriptive statistical methods, Global Moran's I, local Getis-Ord Gi* statistic, and spatial scan statistic.ResultsA total of 463 SFTS cases including 53 (11.45%) deaths were reported from 2011 to 2019 in Zhejiang Province, and the annual number of cases showed increasing tendency. SFTS cases were reported in almost half of the counties (40/89) of Zhejiang Province. Elderly farmers accounted for most cases and the proportion of farmers has increased. Most cases (81.21%) occurred during April and August. The interval from illness onset to confirmation was significantly shortened (Z = 5.194, p < 0.001). The majority of cases were reported in Zhoushan City from 2011 to 2016, but most cases were reported in Taizhou City since 2017.DiscussionWe observed dynamic changes in the seasonal distribution, geographical distribution, and demographic features of SFTS, and comprehensive intervention measures, such as clearance of breeding sites, killing of tick adults, and health education should be strengthened in farmers of the key areas according to the changed epidemiological characteristics.