Severe fever with thrombocytopenia syndrome (SFTS) possibly associated with a Mustela sibirica: a case report from China

Background Severe fever with thrombocytopenia syndrome (SFTS) is a life-threatening tick-borne viral disease with high mortality and limited treatment options. Understanding its transmission routes is essential for effective prevention and control. Case presentation: We report a case of a 55-year-old woman who developed high fever, malaise and diarrhea five days after being bitten by a Mustela sibirica (Siberian weasel). SFTS was diagnosed on day 12 via metagenomic next-generation sequencing (mNGS) of peripheral blood. Despite timely antiviral and supportive treatment, the patient rapidly progressed to multiple organ dysfunction and had a poor prognosis. She had no known exposure to ticks or other animals, raising strong suspicion of SFTSV transmission through the weasel bite. Conclusion This is the first reported case of SFTS possibly linked to a M. sibirica bite, offering novel insight into potential alternative zoonotic transmission routes of SFTSV. These findings highlight the urgent need for surveillance of animal hosts in endemic regions to better understand transmission pathways.