SFTS (Severe Fever with Thrombocytopenia Syndrome) virus particle, illustration. The SFTS virus particle consists of an RNA (ribonucleic acid) genome enclosed in a protein capsid, surrounded by a glycoprotein envelope. There are two types of glycoprotein (red and orange) in the envelope that are involved in fusion with the host cell. SFTS virus is a tick-borne virus that can infect humans. Infected animals can act as reservoirs of SFTS without symptoms. Symptoms in humans include vomiting, diarrhoea and thrombocytopenia (low platelet count). SFTS was first discovered in rural central and eastern China in 2009.