SFTS virus

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colspan=2 style="text-align: center; background-color: rgb(250,250,190)" | Severe Fever with Thrombocytopenia Syndrome Virus
Electron micrograph of SFTS virus
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Species	''Severe fever with thrombocytopenia syndrome virus''

Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) is a tick-borne virus that causes severe fever with thrombocytopenia syndrome (SFTS), a disease characterized by high fever, gastrointestinal symptoms, and thrombocytopenia. SFTSV is a member of the Bunyavirales order, within the Phenuiviridae family, and is classified under the genus Banyangvirus.

Virology

SFTSV is an enveloped virus with a segmented, negative-sense RNA genome. The genome consists of three segments: the large (L), medium (M), and small (S) segments. The L segment encodes the RNA-dependent RNA polymerase, the M segment encodes the glycoproteins Gn and Gc, and the S segment encodes the nucleocapsid protein and a non-structural protein.

Transmission

SFTSV is primarily transmitted to humans through the bite of infected ticks, particularly the Haemaphysalis longicornis tick. Human-to-human transmission has also been reported, especially in healthcare settings, through contact with blood or bodily fluids of infected individuals.

Epidemiology

SFTS was first identified in China in 2009 and has since been reported in several East Asian countries, including South Korea and Japan. The disease is most prevalent in rural areas where tick exposure is common. The case fatality rate of SFTS can be as high as 30%.

Clinical Features

Patients with SFTS typically present with high fever, fatigue, gastrointestinal symptoms such as nausea and diarrhea, and thrombocytopenia (low platelet count). Other laboratory findings may include leukopenia (low white blood cell count) and elevated liver enzymes. Severe cases can progress to multi-organ failure and death.

Diagnosis

Diagnosis of SFTS is based on clinical symptoms, epidemiological history, and laboratory tests. Laboratory confirmation can be achieved through reverse transcription-polymerase chain reaction (RT-PCR) to detect viral RNA, serological tests to detect antibodies, or virus isolation.

Treatment

There is no specific antiviral treatment for SFTS. Management is primarily supportive, focusing on maintaining fluid and electrolyte balance, and treating complications such as bleeding and organ failure. Ribavirin has been used in some cases, but its efficacy is not well established.

Prevention

Preventive measures include avoiding tick bites by wearing protective clothing, using insect repellents, and avoiding areas with high tick activity. Healthcare workers should use standard precautions to prevent nosocomial transmission.

Research

Research is ongoing to better understand the pathogenesis of SFTSV, develop effective treatments, and create vaccines to prevent infection.

Also see

• Bunyavirales
• Tick-borne diseases
• Viral hemorrhagic fevers
• Phenuiviridae