Epidemiological investigation of a cluster of rural severe fever with thrombocytopenia syndrome cases and tick ecological monitoring results in Zibo City
10.3969/j.issn.1005-0507.2026.02.009
- VernacularTitle:淄博市一起农村发热伴血小板减少综合征聚集性疫情流行病学调查及蜱生态学监测结果分析
- Author:
Jun DU
1
;
Ai-min FENG
2
;
Bao-qiang CUI
2
;
Tao SUN
1
;
Yi-chuan YANG
1
;
Yan-dong WANG
1
Author Information
1. Zibo Center for Disease Control and Prevention, Zibo 255026, Shandong, China
2. Yiyuan County Center for Disease Control and Prevention, Zibo 256100, Shandong, China
- Publication Type:Journal Article
- Keywords:
Severe fever with thrombocytopenia syndrome;
Epidemiological investigation;
Cluster epidemic;
Tick density;
Ecological surveillance
- From:
Acta Parasitologica et Medica Entomologica Sinica
2026;33(2):128-133
- CountryChina
- Language:Chinese
-
Abstract:
Objective To understand the epidemiological characteristics of a clustered outbreak of severe fever with thrombocytopenia syndrome(SFTS)as well as the ecological tick monitoring results for Zibo City, and to provide a scientific basis for formulating prevention and control strategies. Methods A case definition was cited before epidemic investigations were performed. Epidemiological investigations were performed on the index cases and their close contacts. Blood samples were collected from cases and close contacts, and quantitative real-time RT-PCR was used to detect SFTS virus(SFTSV)nucleic acid sequences. A retrospective cohort study was conducted to analyze risk factors and develop prevention and control strategies. Results This clustered outbreak involved two index cases and six close contacts with no deaths. Case A exhibited symptom onset on July 26. SFTS was confirmed on August 2. Case B exhibited symptom onset on August 1, and SFTS was confirmed on August 3. Patient B reported a recent history of tick bites. In both index cases, the incubation period for SFTS was inferred to be 7-12 days. The time interval from symptom onset to clinical diagnosis in the two cases ranged from 2-8 days, with an average period of 5 days. SFTSV nucleic acid test result were positive for both patients, whereas all six close contacts tested negative. All captured ticks tested negative for SFTSV using quantitative real-time RT-PCR. The densities of parasitic and free-living ticks in the emergency monitoring area around the cases were 12.60 and 4.65 ticks/(flag·100 m). In 2024, the average parasitic tick index and free-living tick density index were 4.21 and 2.43 ticks/(flag ·100 m)in Yiyuan County, respectively. Conclusions No evidence of human-to-human transmission was found in the assessed SFTS clusters. The infections were likely acquired through tick bites during fieldwork, and the risk of a subsequent outbreak spreading was low.
