SFTS

Severe Fever with Thrombocytopenia Syndrome is an emerging infectious disease caused by SFTS virus, a tick-borne phenuivirus classified within the genus Bandavirus of the family Phenuiviridae. The disease was first characterized in clinical settings in northeastern and central China during 2009, marking its recognition as a distinct nosological entity. The etiologic agent represents a member of the Bunyavirales order, specifically adapted to tick vectors and mammalian hosts in endemic regions. SFTS has since been identified across multiple countries in East and Southeast Asia, indicating broader geographic distribution than initially recognized.

SFTS manifests clinically with an acute febrile illness accompanied by prominent hematological abnormalities, most notably thrombocytopenia and leukopenia, which serve as key diagnostic indicators. Patients commonly present with systemic symptoms including high fever, vomiting, and diarrhea, reflecting the generalized inflammatory and viremic response to infection. The disease course may progress to multiple organ failure in severe cases, contributing substantially to its mortality burden. Laboratory findings typically reveal elevated liver enzyme levels, indicating hepatic involvement in the pathogenic process. The case fatality rate averages approximately 12% overall but may exceed 30% in certain geographic areas, suggesting regional variations in viral virulence, host factors, or healthcare access.

SFTS emerged as a recognized clinical entity in 2009 following initial descriptions from northeastern and central China, where the first documented cases were identified and characterized. The geographic distribution has expanded considerably, with the virus now documented in Japan, South Korea, Vietnam, and Taiwan as of 2015, indicating establishment across multiple East Asian countries. A significant outbreak was reported in East China during the early months of 2020, highlighting the ongoing transmission risk and persistence of the pathogen in endemic regions. The disease is classified as an emerging infectious disease, suggesting continued evolution in its epidemiological profile and potential for further geographic spread. Regional fatality rates vary substantially, ranging from approximately 12% to over 30% in some areas, indicating heterogeneity in disease severity across different populations and viral strains.

SFTS virus is transmitted to humans primarily through tick bites, establishing the arthropod vector as the principal exposure mechanism in natural transmission cycles. The tick-borne nature of the pathogen places individuals with occupational or recreational exposure to tick-infested environments at elevated risk of infection. While the primary transmission route involves tick vectors, the source material does not provide comprehensive detail regarding secondary transmission pathways such as person-to-person spread or other potential exposure routes. Further epidemiological characterization would be required to fully delineate the complete transmission ecology of this pathogen.

Source-backed detail regarding specific high-risk groups for SFTS is not yet available from the provided source material. Based on the tick-borne transmission route, individuals with occupational exposure to tick habitats, including agricultural workers, forestry personnel, and outdoor recreationists, would theoretically face elevated exposure risk. Residents of endemic areas with frequent outdoor activity in tick-infested environments represent another population warranting heightened awareness. The source material does not provide specific information regarding age groups, immunocompromised status, or other host factors that may influence susceptibility or disease severity.

Source-backed detail regarding specific prevention measures for SFTS is not yet available from the provided source material. General principles of tick-borne disease prevention would include avoidance of tick-infested areas, use of protective clothing and repellents, and prompt tick removal following exposure. Public health authorities in endemic areas typically recommend surveillance of tick populations and public education regarding tick bite prevention as foundational control strategies. The absence of an available vaccine, as indicated by the source material, underscores the importance of non-pharmaceutical interventions in disease prevention.

SFTS should be incorporated into differential diagnostic considerations for patients presenting with acute febrile illness and thrombocytopenia in endemic areas or among individuals with recent travel to affected regions. The disease's expanding geographic distribution and emergence in new countries necessitates maintained clinical awareness among healthcare providers outside historically recognized endemic zones. Surveillance systems should account for the seasonal patterns typical of tick-borne diseases, with heightened vigilance during periods of increased tick activity. The substantial case fatality rate underscores the importance of early recognition and supportive care, making SFTS a notifiable condition in several affected jurisdictions.

1. 1 Wikidata. San Francisco Theological Seminary.
2. 2 Wikipedia. SFTS virus.

ICD-10

A98.8

ICD-11

1D6Y

Total cases

2K

Total deaths

25

Peak month

2026-04

Coverage

2 reporting countries · 2026-01-01 → 2026-05-02