Clinical features

• key features of SFTS are high fever and a low platelet count
  
  
• illness begins with a non-specific, viraemic prodrome, which is often flu-like and associated with fever
  • gastrointestinal disturbances may also be present, including abdominal pain, vomiting and diarrhoea
  • prodrome lasts for around 7 days
  • incubation period is 7 to 14 days, typically around 9 days
    
    
• appears to be a spectrum of disease, with some patients only having a mild illness, which resolves spontaneously.In those who have progressive disease, severe illness typically develops in the second week
  • in those who survive severe illness, signs of recovery usually emerge around days 8 to 11 of illness, accompanied by a decrease in blood viral load and recovery of the platelet count
  • in fatal cases, high-level viraemia and thrombocytopaenia persist or worsen; often associated with increasing blood levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
    
    
• reported complications include acute kidney injury, myocarditis, haemorrhage (including disseminated intravascular haemorrhage), meningioencephalitis, haemophagocytic lymphohistiocytosis, and multi-organ dysfunction

Reference:

• Public Health England (April 2021). Severe fever with thrombocytopaenia syndrome (SFTS): epidemiology, outbreaks and guidance