Severe fever with thrombocytopenia syndrome

Disease Description (Causes and Symptoms)

• Disease name: Severe fever with thrombocytopenia syndrome (SFTS) — This is the medically used name.
• Cause: The SFTS virus (SFTSV, currently classified as a virus belonging to the Dabie bandavirus/Phenuiviridae group) is transmitted to humans through bites from infected ticks (mainly the Asian longhorned tick, Haemaphysalis spp.). Person-to-person transmission through contact with the blood or bodily fluids of an infected person has also been reported. Cases occur more frequently during the seasonal period of tick activity (spring to autumn).
• Pathophysiology (summary): Direct cellular damage caused by viral infection combines with immune-mediated inflammatory responses (cytokine storm), which may lead to decreased platelets and white blood cells, liver and kidney damage, intravascular coagulation abnormalities, and multiple organ failure.
• Main symptoms: Sudden high fever (often 39–40°C or higher), fatigue, loss of appetite, gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain, headache, muscle pain, and enlarged lymph nodes. Common laboratory findings include thrombocytopenia, leukopenia, and elevated liver enzymes. In severe cases, bleeding, impaired consciousness, kidney failure, respiratory failure, and multiple organ failure may occur.

Treatment Methods

• Standard treatment overview: There is currently no definitively approved specific antiviral drug or vaccine. Treatment mainly consists of intensive supportive care for symptoms and complications.
• Antiviral drugs:
  • No specific treatment has been established as the standard. Favipiravir has been used or studied in some research and clinical settings, while ribavirin lacks consistent evidence of efficacy. The use of medications depends on institutional guidelines, clinical status, and expert judgment.
• Supportive treatment (depending on severity):
  • Hospital observation and fluid and electrolyte management, symptomatic treatment such as antipyretics and analgesics
  • Platelet transfusion in cases of thrombocytopenia or bleeding, and appropriate coagulation treatment for coagulation abnormalities
  • Vasoactive drugs and intensive treatment (intensive care unit) in cases of sepsis or shock
  • Hemodialysis (renal replacement therapy) if needed in cases of kidney failure
  • Appropriate antibiotics if a secondary bacterial infection is suspected
• Infection control: Avoid contact with the patient’s blood and bodily fluids and follow standard and barrier (contact/droplet) infection-control precautions
• Lifestyle management and precautions:
  • If there is a risk of tick exposure, minimize skin exposure (long sleeves, long pants, socks, and gloves), use repellents (such as DEET), and check clothing and shoes
  • If bitten by a tick, do not forcibly remove it yourself; have it safely removed at a medical institution or seek medical advice
  • Visit a medical institution promptly and undergo diagnostic testing (blood tests, RT‑PCR, etc.) if fever or gastrointestinal symptoms develop
• Complication management: Specialized intensive treatment is required if DIC (disseminated intravascular coagulation), multiple organ failure, central nervous system complications, or other complications occur

Checklist Before an Outpatient Visit (Including Items to Bring, Records, and Sample Questions)

• Items to bring/provide:
  • List of medications currently being taken (including prescription drugs, OTC drugs, and supplements)
  • Underlying conditions and medical history (especially liver or kidney disease, immunosuppression, and whether anticoagulants are being taken)
  • Date symptoms began and their progression (fever progression and temperature records), and whether vomiting, diarrhea, or bleeding symptoms are present
  • Whether a tick bite occurred (when, where, how it was removed, etc.), as well as animal contact and recent travel history
  • Recent test results (such as blood test results, if available)
• Points to note before the outpatient visit:
  • Go immediately to the emergency room if severe symptoms such as fever, bleeding, or changes in consciousness occur
  • Diagnostic testing is needed as soon as possible after symptoms appear (especially when there is a history of fever and tick exposure)

Examples of General Questions to Ask the Doctor

• "What tests are needed for my current condition (such as blood tests or viral tests)?"
• "What treatment options are recommended, and what are their expected effects and side effects?"
• "How likely is it that hospitalization or intensive care will be necessary?"
• "What is the risk of transmitting the infection to other people (family members), and what infection-prevention measures should be taken at home?"
• "Are follow-up tests or long-term follow-up needed after recovery?"

Examples of Disease-Specific Questions

• "If I develop a fever within how many days after tick exposure should I be tested for SFTS, and what are the testing method and sensitivity?"
• "If my blood tests (platelet count, liver function, and white blood cell count) indicate a high risk of severe disease, what additional treatment would you recommend (for example, use of antiviral drugs or hospitalization)?"