Epidemiological and clinical characteristics of severe fever with thrombocytopenia syndrome bunyavirus human-to-human transmission

PLoS Negl Trop Dis. 2021 Apr 30;15(4):e0009037. doi: 10.1371/journal.pntd.0009037. eCollection 2021 Apr.

Abstract

Background: Severe fever with thrombocytopenia syndrome (SFTS) was listed as one of the most severe infectious disease by world health organization in 2017. It can mostly be transmitted by tick bite, while human-to-human transmission has occurred on multiple occasions. This study aimed to explore the epidemiological and clinical characteristics and make risk analysis of SFTS human-to-human transmission.

Methods: Descriptive and spatial methods were employed to illustrate the epidemiological and clinical characteristics of SFTS human-to-human transmission. The risk of SFTS human-to-human transmission was accessed through secondary attack rate (SAR) and basic reproductive number (R0). Logistic regression analysis was used to identify the associated risk factors.

Results: A total of 27 clusters of SFTS human-to-human transmission were reported in China and South Korea during 1996-2019. It mainly occurred among elder people in May, June and October in central and eastern China. The secondary cases developed milder clinical manifestation and better outcome than the index cases. The incubation period was 10.0 days (IQR:8.0-12.0), SAR was 1.72%-55.00%, and the average R0 to be 0.13 (95%CI:0.11-0.16). Being blood relatives of the index case, direct blood/bloody secretion contact and bloody droplet contact had more risk of infection (OR = 6.35(95%CI:3.26-12.37), 38.01 (95%CI,19.73-73.23), 2.27 (95%CI,1.01-5.19)).

Conclusions: SFTS human-to-human transmission in China and South Korea during 1996-2019 had obvious spatio-temporal distinction. Ongoing assessment of this transmission risk is crucial for public health authorities though it continues to be low now.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • China
  • Contact Tracing
  • Female
  • Fever / complications
  • Fever / epidemiology*
  • Fever / virology
  • Humans
  • Incidence
  • Logistic Models
  • Male
  • Middle Aged
  • Phlebovirus / genetics
  • Phlebovirus / isolation & purification
  • Phlebovirus / physiology*
  • Republic of Korea
  • Risk Assessment
  • Risk Factors
  • Severe Fever with Thrombocytopenia Syndrome / epidemiology
  • Severe Fever with Thrombocytopenia Syndrome / transmission*
  • Severe Fever with Thrombocytopenia Syndrome / virology
  • Spatio-Temporal Analysis

Grants and funding

CJB received funding from Jiangsu Provincial Major Science & Technology Demonstration Project (No. BE2017749); WDL received funding from Jiangsu Provincial natural Science Foundation (No. BK20151595) and Jiangsu Provincial Medical Major Talent and Youth Talent (No.ZDRC2016032 & QNRC2016542); CJB and WDL received funding from Key Medical Discipline of Epidemiology (No. ZDXK A2016008). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.